The document proposes a new scheme for secure communication in fiber optic systems using broadband optical noise. In the scheme, Alice and Bob receive identical replicas of a truly random broadband optical noise signal. They extract identical random binary sequences from the noise to use as an encryption key. The key is distributed through the use of identical optical scramblers by Alice and Bob, whose structures are not known to an eavesdropper Eve. The scheme allows for high data rates like conventional fiber systems and can be integrated into existing infrastructure.
A Survey on Secure Alternate Path Selection for Enhanced Network Lifetime in ...IRJET Journal
This document summarizes a research paper that proposes techniques to enhance the lifetime of wireless sensor networks. It discusses how sensor nodes closer to the sink node consume more energy transmitting data, creating hotspots and shortening the network's lifetime. To address this, the paper proposes using alternate shortest paths to route data and relocating the sink node when the energy of alternate paths gets low. It also uses elliptic curve cryptography and a hybrid encryption method using AES and ECC to securely transmit data and further increase the network lifetime. Evaluation results show the proposed energy-aware sink relocation technique effectively enhances the network lifetime of wireless sensor networks.
A Novel Three-Dimensional Adaptive Localization (T-Dial) Algorithm for Wirele...iosrjce
The document presents a novel three-dimensional adaptive localization (T-Dial) algorithm for wireless sensor networks. The proposed algorithm works in four primary phases: 1) Neighbor formation where nodes broadcast information to nodes within transmission range to form neighbor tables; 2) Group formation where anchor nodes connect to non-anchor nodes to divide the network into smaller manageable groups; 3) Edge node marking where edge nodes on the network boundary are detected and marked; and 4) Localization error correction where missing nodes from initial setup are rediscovered and corrected. Simulation results show the proposed algorithm improves localization rate, reduces localization error, and increases positioning rate compared to existing algorithms.
This document summarizes localization algorithms in wireless sensor networks. It discusses how node localization is an important challenge for wireless sensor networks. It reviews different approaches to node localization, including centralized and distributed algorithms. Centralized algorithms migrate data to a central station, while distributed algorithms perform computations locally. Specific algorithms discussed include MDS-MAP, simulated annealing approaches, beacon-based, relaxation-based, and coordinate system stitching approaches. The document also discusses hybrid localization techniques and future challenges in improving localization.
Secure communications over wireless broadcast networkspraveen369
The document describes a shortest seek first algorithm for scheduling requests on a disk drive. The algorithm scans the request queue for the request closest to the disk head's current position and services that request first to minimize seeking time. While this reduces average response time compared to a FIFO queue, requests further away could starve if new requests keep arriving near the head. The elevator algorithm is presented as an alternative that services requests in the direction of disk head movement to avoid starvation and further reduce seeking time.
IMPLEMENTATION OF SECURITY PROTOCOL FOR WIRELESS SENSORijcsa
Intrusion Detection is one of the methods of defending against these attacks. In the proposed a security protocol for homogeneous wireless sensor network; network with all nodes are of same type. Clustering is used to improve the energy efficiency. Zone-Based Cluster Protocol (ZBCA) is used for selection of cluster head which is effective in scalability and energy consumption. Single hop technique is used for
communication within normal nodes and cluster head to base station. Simulation of proposed algorithm is performed in MATLAB. Sleep Deprivation Attack has been analyzed where attacker changes the environmental values by an artificial event. Attacker produces an event in environment due to which nodes have to sense the environment more than once in the same round that increase the power consumption of
the node. This interrupt reduces the network life time as nodes are not allowed to go in sleep mode and they are not able to perform their function of data collection and reporting to Cluster head and Base Station properly. Proposed protocol identifies this attack and prevents it from happening by solating the attacker node.
Secure and Efficient Data Transmission forCluster-based Wireless Sensor Netw...AJIT M KARANJKAR
Secure and Efficient Data Transmission (SET) protocols for cluster based wireless sensor network (CWSN), called SET-IBS and SET-IBOOS, by using the identity-based digital signature (IBS) scheme and the identity-based online/offline digital signature (IBOOS) scheme, respectively.
SCALABILITY CONCERNS OF CHIRP SPREAD SPECTRUM FOR LPWAN APPLICATIONSijasuc
Divergent modulation schemes have been proposed for the Internet of Things (IoT). Low Power Wide Area
Networks (LPWAN) technologies are gaining unprecedented acceptance in IoT application of sensor
networks. Chirp Spread Spectrum (CSS) is a prominent modulation technique proposed for LPWAN. Chirps
can traverse long distance and are resilient to noise and Doppler effects. Noise resilience along with
transmission range and low power requirement makes CSS a preferred modulation scheme for sensor
networks. LoRaWANTM, with its physical (PHY) layer using CSS, has emerged as the widely accepted
LPWAN solution. By using CSS modulation with orthogonal spreading factors (SF), LoRa offers wide
coverage to LPWAN applications while supporting a high volume of devices. However, scalability
performance of CSS has not been inadequately modeled. As with the suitability of the modulation scheme,
there are concerns on how chirps interact with the surrounding as the number of deployments bursts out
into higher volumes. We evaluate CSS at ISM band 868 MHz for spreading factor 7 to 12 at bandwidth 125
kHz for performance and scalability. Simultaneous transmissions were simulated with repeated iterations
and conclusions are arrived on collisions rate, packet error rate, and bit error. Suitability of using CSS for
sensor networks for future deployments is commended.
Energy efficient intrusion detection systemiaemedu
This document discusses energy efficient intrusion detection systems for wireless sensor networks. It proposes a hybrid intrusion detection system (HIDS) that considers both the energy consumption and past behavior of nodes. The HIDS classifies nodes as malicious or normal using an energy prediction approach, and then further analyzes abnormal packets sent by malicious nodes using a misuse detection module. By taking both energy patterns and past transmissions into account, the proposed HIDS aims to more accurately detect intrusions while minimizing energy usage compared to other intrusion detection schemes for wireless sensor networks.
A Survey on Secure Alternate Path Selection for Enhanced Network Lifetime in ...IRJET Journal
This document summarizes a research paper that proposes techniques to enhance the lifetime of wireless sensor networks. It discusses how sensor nodes closer to the sink node consume more energy transmitting data, creating hotspots and shortening the network's lifetime. To address this, the paper proposes using alternate shortest paths to route data and relocating the sink node when the energy of alternate paths gets low. It also uses elliptic curve cryptography and a hybrid encryption method using AES and ECC to securely transmit data and further increase the network lifetime. Evaluation results show the proposed energy-aware sink relocation technique effectively enhances the network lifetime of wireless sensor networks.
A Novel Three-Dimensional Adaptive Localization (T-Dial) Algorithm for Wirele...iosrjce
The document presents a novel three-dimensional adaptive localization (T-Dial) algorithm for wireless sensor networks. The proposed algorithm works in four primary phases: 1) Neighbor formation where nodes broadcast information to nodes within transmission range to form neighbor tables; 2) Group formation where anchor nodes connect to non-anchor nodes to divide the network into smaller manageable groups; 3) Edge node marking where edge nodes on the network boundary are detected and marked; and 4) Localization error correction where missing nodes from initial setup are rediscovered and corrected. Simulation results show the proposed algorithm improves localization rate, reduces localization error, and increases positioning rate compared to existing algorithms.
This document summarizes localization algorithms in wireless sensor networks. It discusses how node localization is an important challenge for wireless sensor networks. It reviews different approaches to node localization, including centralized and distributed algorithms. Centralized algorithms migrate data to a central station, while distributed algorithms perform computations locally. Specific algorithms discussed include MDS-MAP, simulated annealing approaches, beacon-based, relaxation-based, and coordinate system stitching approaches. The document also discusses hybrid localization techniques and future challenges in improving localization.
Secure communications over wireless broadcast networkspraveen369
The document describes a shortest seek first algorithm for scheduling requests on a disk drive. The algorithm scans the request queue for the request closest to the disk head's current position and services that request first to minimize seeking time. While this reduces average response time compared to a FIFO queue, requests further away could starve if new requests keep arriving near the head. The elevator algorithm is presented as an alternative that services requests in the direction of disk head movement to avoid starvation and further reduce seeking time.
IMPLEMENTATION OF SECURITY PROTOCOL FOR WIRELESS SENSORijcsa
Intrusion Detection is one of the methods of defending against these attacks. In the proposed a security protocol for homogeneous wireless sensor network; network with all nodes are of same type. Clustering is used to improve the energy efficiency. Zone-Based Cluster Protocol (ZBCA) is used for selection of cluster head which is effective in scalability and energy consumption. Single hop technique is used for
communication within normal nodes and cluster head to base station. Simulation of proposed algorithm is performed in MATLAB. Sleep Deprivation Attack has been analyzed where attacker changes the environmental values by an artificial event. Attacker produces an event in environment due to which nodes have to sense the environment more than once in the same round that increase the power consumption of
the node. This interrupt reduces the network life time as nodes are not allowed to go in sleep mode and they are not able to perform their function of data collection and reporting to Cluster head and Base Station properly. Proposed protocol identifies this attack and prevents it from happening by solating the attacker node.
Secure and Efficient Data Transmission forCluster-based Wireless Sensor Netw...AJIT M KARANJKAR
Secure and Efficient Data Transmission (SET) protocols for cluster based wireless sensor network (CWSN), called SET-IBS and SET-IBOOS, by using the identity-based digital signature (IBS) scheme and the identity-based online/offline digital signature (IBOOS) scheme, respectively.
SCALABILITY CONCERNS OF CHIRP SPREAD SPECTRUM FOR LPWAN APPLICATIONSijasuc
Divergent modulation schemes have been proposed for the Internet of Things (IoT). Low Power Wide Area
Networks (LPWAN) technologies are gaining unprecedented acceptance in IoT application of sensor
networks. Chirp Spread Spectrum (CSS) is a prominent modulation technique proposed for LPWAN. Chirps
can traverse long distance and are resilient to noise and Doppler effects. Noise resilience along with
transmission range and low power requirement makes CSS a preferred modulation scheme for sensor
networks. LoRaWANTM, with its physical (PHY) layer using CSS, has emerged as the widely accepted
LPWAN solution. By using CSS modulation with orthogonal spreading factors (SF), LoRa offers wide
coverage to LPWAN applications while supporting a high volume of devices. However, scalability
performance of CSS has not been inadequately modeled. As with the suitability of the modulation scheme,
there are concerns on how chirps interact with the surrounding as the number of deployments bursts out
into higher volumes. We evaluate CSS at ISM band 868 MHz for spreading factor 7 to 12 at bandwidth 125
kHz for performance and scalability. Simultaneous transmissions were simulated with repeated iterations
and conclusions are arrived on collisions rate, packet error rate, and bit error. Suitability of using CSS for
sensor networks for future deployments is commended.
Energy efficient intrusion detection systemiaemedu
This document discusses energy efficient intrusion detection systems for wireless sensor networks. It proposes a hybrid intrusion detection system (HIDS) that considers both the energy consumption and past behavior of nodes. The HIDS classifies nodes as malicious or normal using an energy prediction approach, and then further analyzes abnormal packets sent by malicious nodes using a misuse detection module. By taking both energy patterns and past transmissions into account, the proposed HIDS aims to more accurately detect intrusions while minimizing energy usage compared to other intrusion detection schemes for wireless sensor networks.
This document proposes using self-organizing maps (SOMs), an unsupervised artificial neural network technique, to categorize sensory data from wireless sensor networks (WSNs) in order to conserve battery power. The proposed system trains a 2x3 SOM on a base station node to categorize data from active sensor nodes. After training, the SOM defines categories that sensor nodes then transmit instead of raw data, reducing transmissions and saving up to 48.5% of battery power. Evaluation of the approach considers battery savings versus number of training samples and transmission interval.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The document summarizes a presentation on reliable and energy-efficient communication in wireless sensor networks. The presentation covered wireless sensor network applications and requirements, experimentation platforms for wireless sensor network research, and research on traffic-adaptive MAC protocols, adaptive forward error correction, and TCP performance optimizations for wireless sensor networks. It provided examples and results from experiments conducted on a wireless sensor network testbed.
Chapter 5 applications of neural networksPunit Saini
Neural networks are being used experimentally in several medical applications, including modeling the cardiovascular system and diagnosing medical conditions. They can be used to detect diseases by learning from examples without needing a specific algorithm. Neural networks are also being explored for applications like implementing electronic noses for telemedicine. Researchers are working to build artificial brains more cheaply using field programmable gate arrays (FPGAs) on commercial boards, which could enable evolving millions of neural network modules at electronic speeds. Genetic algorithms are also being combined with neural networks to help optimize their structure and performance for tasks like object recognition.
This document describes the implementation of a human health monitoring system using Zigbee wireless technology. It presents a prototype that can monitor biomedical signals from multiple biosensors using different communication standards. The prototype utilizes three different sensor types for autonomous healthcare monitoring. It also develops a Zigbee-compliant wireless system offering low power consumption, low cost, and advanced network configuration. Experimental results show the system can successfully perform wireless telemetry, data acquisition, and real-time monitoring of sensor signals over a range of 111 meters outdoors and 33 meters indoors.
Femtocell is a small cellular base station,designe d for use in residential or enterprise. Connects to the service provider�s network via broa dband.Femtocell is one type of Indoor network which provide the wireless access within th e particular area. Femtocells ensure that carefully planned cellular networks which may conne ct anespecially of the citizens to the Internet and with one another. In this paper femtoc ells has such network which maintains the specialty of the data transfer through the network will femtocells prove more trouble than they are worth,femtocells just an exciting but Minimum stage of network evolution that will beimproved Wireless offloading,new backhaul regula tions and/or pricing,or other unforeseen technological developments? This paper overviews th e history of femtocells,demystifies their key aspects,and provides a preview of the next few years� acceleration towards small cell technology. This paper reports,we also position an d introduce the articles that headline this special issue.
Free-Space Optical Networking Using the Spectrum of Visible LightIJTET Journal
Radio frequency technology suffers from limited bandwidth and electromagnetic interference. The recent
developments in solid-state Light Emitting Diode (LED) materials and devices are driving resurgence into the use of Free-Space Optical (FSO) wireless communication. LED-based network transceivers have a variety of competitive advantages over RF
including high bandwidth density, security, energy consumption, and aesthetics. They also use a highly reusable unregulated part of the spectrum (visible light). Many opportunities exist to exploit low-cost nature of LEDs and lighting units for widespread deployment of optical communication. The prime focus is to reducing cost, and for that, we have to make appropriate selection
of system’s components, e.g. modulation, coding, filtering. The objective is to describe the viability of an optical free-space visible light transceiver as a basis for indoor wireless networking and to achieve acceptable bit error rate (BER) performance for indoor use, with a low cost system.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Ant Colony Optimization for Wireless Sensor Network: A Reviewiosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
IRJET- An Hybrid Approach for Enhancement of Energy and Network Life Time...IRJET Journal
This document discusses an hybrid approach to enhance energy efficiency and network lifetime in wireless sensor networks (WSNs) using the PEGASIS routing protocol along with artificial neural networks. PEGASIS is a chain-based protocol that forms chains between sensor nodes to transmit data to the base station, with nodes taking turns acting as the leader to transmit to the base station. The proposed approach uses an improved ant colony algorithm instead of a greedy algorithm to build more optimized chains, and utilizes neural networks to select chain leaders in a way that balances energy consumption between nodes. Simulation results using MATLAB Simulink show the proposed method significantly improves energy efficiency and prolongs network lifetime compared to the original PEGASIS protocol.
Intrusion Detection and Countermeasure in Virtual Network Systems Using NICE ...IJERA Editor
The cloud computing has increased in many organizations. It provides many benefits in terms of low cost and accessibility of data. Ensuring the security of cloud computing is a major factor in the cloud computing environment, as users often store sensitive information with cloud storage providers but these providers may be untrusted. In this project we propose anIntrusion Detection and Countermeasure in Virtual Network Systems mechanism called NICE to prevent vulnerable virtual machines from being compromised in the cloud. NICE detects and mitigates collaborative attacks in the cloud virtual networking environment. The system performance evaluation demonstrates the feasibility of NICE and shows that the proposed solution can significantly reduce the risk of the cloud system from being exploited and abused by internal and external attackers.
As sensor networks edge closer towards wide-spread placement, security issues become a central concern. So far, much research has concentrated on making sensor networks feasible and useful, and has not focused on security.
We present a set of security building blocks optimized for resource constrained environments and wireless communication. SPINS has two secure building blocks: SNEP and TESLA. SNEP provides the following important baseline security primitives: Data confidentiality, two-party data authentication, and data freshness. A particularly hard problem is to provide effective broadcast authentication, which is an important mechanism for sensor networks. TESLA is a new protocol which provides authenticated broadcast for severely resource-constrained surroundings. We realized the above protocols, and show that they are practical straighly on minimal hardware: the performance of the protocol suite easily matches the data rate of our network. Additionally, we prove that the suite can be used for building higher level protocols
The document discusses business continuity strategies for food retailers, using the chocolate shop For the Love of Chocolate as an example. It addresses insurance coverage, backup equipment, food contamination procedures, emergency assistance contacts, and employee education on potential disasters. Key recommendations include expanding the customer base, creating a second location, and developing a chocolate catering business.
The document compares and contrasts different people, objects, and their attributes using comparative and superlative adjectives as well as expressions like "as...as", "enough", and "too". It states that Van Gogh's painting is more famous than a tavern painting, Mount Teide is the tallest mountain in Spain, a yellow car is smaller than a red car, and one man is the ugliest in the world. It also compares intelligence, niceness of houses, size of books, handsomeness of football players versus Messi, size of a hotel, and age for drinking beer.
The document compares and contrasts three films - Titanic, The Outsiders, and Step Up 3D. It notes that Titanic starred Leonardo DiCaprio and Kate Winslet and was based on a real sinking, though the characters were fictional. The Outsiders was based on a book by S.E. Hinton and centered around boys from opposing socioeconomic groups who fight each other. Step Up 3D featured dancing competitions between two bands. Comparisons are made between the films' romantic and dramatic elements.
Patrimacapaca was born in 1964 in Tulcatulba, weighing only 22 kilos but gaining weight quickly. He was a good student throughout primary and secondary school. In secondary school, he wrote and published a successful mystery book called "The Mysterious Next of the House." With the money he earned, he bought a large house but had difficulties with friends who were jealous of his success. He later decided to focus on his studies rather than writing but continued writing throughout his life, publishing 32 books total and having a family of his own.
Harry Potter grew up in Madrid where he attended a prestigious school and showed a talent for acting from a young age. At 15, he convinced his parents to allow him to pursue acting, moving to Hollywood. His first film was a worldwide success, winning him his first Oscar award. While filming, he met and fell in love with Veronica, and they married and had many children together. Unfortunately, Harry died in an accident while crossing the street between filming.
Eustaquia Juliana Coco-Cuadrado Cebevi, better known as "La Blasa", was born in 1918 in Camuñas, Toledo. She attended a school called "The Black Sheep" where she learned sheep shearing and wool jumping. At age 10 she began working with her father and their sheep. At 14 she developed a vision problem called "BLASAPIA" and was given glasses. At 15 doctors detected a back problem and prescribed a brace. At 17 she married "El Tío de la Vara" and they had five children together. They eventually sold their sheep and bought vineyards after their children grew up. "La Blasa" died at age 97 while
O mapa detalha as principais áreas temáticas do Disneyland Resort, incluindo Main Street USA, Adventureland, Frontierland, New Orleans Square, Critter Country, Fantasyland, Mickey's Toon Town e Tomorrowland no Disneyland, bem como áreas no vizinho Disney's California Adventure.
This document proposes using self-organizing maps (SOMs), an unsupervised artificial neural network technique, to categorize sensory data from wireless sensor networks (WSNs) in order to conserve battery power. The proposed system trains a 2x3 SOM on a base station node to categorize data from active sensor nodes. After training, the SOM defines categories that sensor nodes then transmit instead of raw data, reducing transmissions and saving up to 48.5% of battery power. Evaluation of the approach considers battery savings versus number of training samples and transmission interval.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The document summarizes a presentation on reliable and energy-efficient communication in wireless sensor networks. The presentation covered wireless sensor network applications and requirements, experimentation platforms for wireless sensor network research, and research on traffic-adaptive MAC protocols, adaptive forward error correction, and TCP performance optimizations for wireless sensor networks. It provided examples and results from experiments conducted on a wireless sensor network testbed.
Chapter 5 applications of neural networksPunit Saini
Neural networks are being used experimentally in several medical applications, including modeling the cardiovascular system and diagnosing medical conditions. They can be used to detect diseases by learning from examples without needing a specific algorithm. Neural networks are also being explored for applications like implementing electronic noses for telemedicine. Researchers are working to build artificial brains more cheaply using field programmable gate arrays (FPGAs) on commercial boards, which could enable evolving millions of neural network modules at electronic speeds. Genetic algorithms are also being combined with neural networks to help optimize their structure and performance for tasks like object recognition.
This document describes the implementation of a human health monitoring system using Zigbee wireless technology. It presents a prototype that can monitor biomedical signals from multiple biosensors using different communication standards. The prototype utilizes three different sensor types for autonomous healthcare monitoring. It also develops a Zigbee-compliant wireless system offering low power consumption, low cost, and advanced network configuration. Experimental results show the system can successfully perform wireless telemetry, data acquisition, and real-time monitoring of sensor signals over a range of 111 meters outdoors and 33 meters indoors.
Femtocell is a small cellular base station,designe d for use in residential or enterprise. Connects to the service provider�s network via broa dband.Femtocell is one type of Indoor network which provide the wireless access within th e particular area. Femtocells ensure that carefully planned cellular networks which may conne ct anespecially of the citizens to the Internet and with one another. In this paper femtoc ells has such network which maintains the specialty of the data transfer through the network will femtocells prove more trouble than they are worth,femtocells just an exciting but Minimum stage of network evolution that will beimproved Wireless offloading,new backhaul regula tions and/or pricing,or other unforeseen technological developments? This paper overviews th e history of femtocells,demystifies their key aspects,and provides a preview of the next few years� acceleration towards small cell technology. This paper reports,we also position an d introduce the articles that headline this special issue.
Free-Space Optical Networking Using the Spectrum of Visible LightIJTET Journal
Radio frequency technology suffers from limited bandwidth and electromagnetic interference. The recent
developments in solid-state Light Emitting Diode (LED) materials and devices are driving resurgence into the use of Free-Space Optical (FSO) wireless communication. LED-based network transceivers have a variety of competitive advantages over RF
including high bandwidth density, security, energy consumption, and aesthetics. They also use a highly reusable unregulated part of the spectrum (visible light). Many opportunities exist to exploit low-cost nature of LEDs and lighting units for widespread deployment of optical communication. The prime focus is to reducing cost, and for that, we have to make appropriate selection
of system’s components, e.g. modulation, coding, filtering. The objective is to describe the viability of an optical free-space visible light transceiver as a basis for indoor wireless networking and to achieve acceptable bit error rate (BER) performance for indoor use, with a low cost system.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Ant Colony Optimization for Wireless Sensor Network: A Reviewiosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
IRJET- An Hybrid Approach for Enhancement of Energy and Network Life Time...IRJET Journal
This document discusses an hybrid approach to enhance energy efficiency and network lifetime in wireless sensor networks (WSNs) using the PEGASIS routing protocol along with artificial neural networks. PEGASIS is a chain-based protocol that forms chains between sensor nodes to transmit data to the base station, with nodes taking turns acting as the leader to transmit to the base station. The proposed approach uses an improved ant colony algorithm instead of a greedy algorithm to build more optimized chains, and utilizes neural networks to select chain leaders in a way that balances energy consumption between nodes. Simulation results using MATLAB Simulink show the proposed method significantly improves energy efficiency and prolongs network lifetime compared to the original PEGASIS protocol.
Intrusion Detection and Countermeasure in Virtual Network Systems Using NICE ...IJERA Editor
The cloud computing has increased in many organizations. It provides many benefits in terms of low cost and accessibility of data. Ensuring the security of cloud computing is a major factor in the cloud computing environment, as users often store sensitive information with cloud storage providers but these providers may be untrusted. In this project we propose anIntrusion Detection and Countermeasure in Virtual Network Systems mechanism called NICE to prevent vulnerable virtual machines from being compromised in the cloud. NICE detects and mitigates collaborative attacks in the cloud virtual networking environment. The system performance evaluation demonstrates the feasibility of NICE and shows that the proposed solution can significantly reduce the risk of the cloud system from being exploited and abused by internal and external attackers.
As sensor networks edge closer towards wide-spread placement, security issues become a central concern. So far, much research has concentrated on making sensor networks feasible and useful, and has not focused on security.
We present a set of security building blocks optimized for resource constrained environments and wireless communication. SPINS has two secure building blocks: SNEP and TESLA. SNEP provides the following important baseline security primitives: Data confidentiality, two-party data authentication, and data freshness. A particularly hard problem is to provide effective broadcast authentication, which is an important mechanism for sensor networks. TESLA is a new protocol which provides authenticated broadcast for severely resource-constrained surroundings. We realized the above protocols, and show that they are practical straighly on minimal hardware: the performance of the protocol suite easily matches the data rate of our network. Additionally, we prove that the suite can be used for building higher level protocols
The document discusses business continuity strategies for food retailers, using the chocolate shop For the Love of Chocolate as an example. It addresses insurance coverage, backup equipment, food contamination procedures, emergency assistance contacts, and employee education on potential disasters. Key recommendations include expanding the customer base, creating a second location, and developing a chocolate catering business.
The document compares and contrasts different people, objects, and their attributes using comparative and superlative adjectives as well as expressions like "as...as", "enough", and "too". It states that Van Gogh's painting is more famous than a tavern painting, Mount Teide is the tallest mountain in Spain, a yellow car is smaller than a red car, and one man is the ugliest in the world. It also compares intelligence, niceness of houses, size of books, handsomeness of football players versus Messi, size of a hotel, and age for drinking beer.
The document compares and contrasts three films - Titanic, The Outsiders, and Step Up 3D. It notes that Titanic starred Leonardo DiCaprio and Kate Winslet and was based on a real sinking, though the characters were fictional. The Outsiders was based on a book by S.E. Hinton and centered around boys from opposing socioeconomic groups who fight each other. Step Up 3D featured dancing competitions between two bands. Comparisons are made between the films' romantic and dramatic elements.
Patrimacapaca was born in 1964 in Tulcatulba, weighing only 22 kilos but gaining weight quickly. He was a good student throughout primary and secondary school. In secondary school, he wrote and published a successful mystery book called "The Mysterious Next of the House." With the money he earned, he bought a large house but had difficulties with friends who were jealous of his success. He later decided to focus on his studies rather than writing but continued writing throughout his life, publishing 32 books total and having a family of his own.
Harry Potter grew up in Madrid where he attended a prestigious school and showed a talent for acting from a young age. At 15, he convinced his parents to allow him to pursue acting, moving to Hollywood. His first film was a worldwide success, winning him his first Oscar award. While filming, he met and fell in love with Veronica, and they married and had many children together. Unfortunately, Harry died in an accident while crossing the street between filming.
Eustaquia Juliana Coco-Cuadrado Cebevi, better known as "La Blasa", was born in 1918 in Camuñas, Toledo. She attended a school called "The Black Sheep" where she learned sheep shearing and wool jumping. At age 10 she began working with her father and their sheep. At 14 she developed a vision problem called "BLASAPIA" and was given glasses. At 15 doctors detected a back problem and prescribed a brace. At 17 she married "El Tío de la Vara" and they had five children together. They eventually sold their sheep and bought vineyards after their children grew up. "La Blasa" died at age 97 while
O mapa detalha as principais áreas temáticas do Disneyland Resort, incluindo Main Street USA, Adventureland, Frontierland, New Orleans Square, Critter Country, Fantasyland, Mickey's Toon Town e Tomorrowland no Disneyland, bem como áreas no vizinho Disney's California Adventure.
The document makes comparisons between various objects using attributes such as size, cost, age, beauty. It compares cars, people, animals, electronics, books, hats based on being bigger, smaller, older, more expensive, more beautiful and other relative attributes. Many of the objects are described as being too big, small, expensive or other extremes to fit somewhere or be acquired.
PHYSICAL LAYER SECURITY OF OPTICAL NETWORKS.pdfadeel paracha
Abstract
The physical layer of an optical network may be attacked in numerous ways, such as by jamming, assaults on the physical infrastructure, eavesdropping, and interception. As the requirement for network capacity develops, the physical layer of the optical network must be kept secure. In this overview article, specialists look at security problems in optical networks and discuss a variety of novel approaches to defending optical networks. In the first section of this study, researchers discuss a variety of security issues that might harm the optical layer of an optical network. These weaknesses include jamming, physical infrastructure assaults, eavesdropping, and interception. Enhanced optical network security has gained a lot of interest in the sectors described above. Real-time signal processing is essential in order to apply security measures at the physical layer without slowing down the pace of optical communications. The key advantages of optical processing for optical layer security include rapid reaction, wide-band operation, resilience to electromagnetic fields, compact size, and low latency. In the second part of this research, we look into optical steganography, optical encryption, optical code-division multiple access (CDMA) secrecy, self-healing, survivable optical rings, anti-jamming, and optical CDMA confidentiality.
I. Introduction
Introduction Optical communication systems are employed in many different fields, including business, the military, and personal communication. Optical networks are unusual in that their data speeds are greater than 40 GB/s, and this figure will only increase as time goes on. Physical layer security measures have to function in real time, which is not achievable with standard electronic computing. Side-channel assaults are less likely to emerge in optical communication networks because optical components don’t leave electromagnetic traces. With optical encryption, communications may be encrypted fast and with minimum latency (at speeds not attainable with standard electrical implementations) (at rates not possible with conventional electrical implementations). In addition to data encryption, optical steganography may be used to obscure the flow of data over an open transmission channel.
II. Threats and defenses in optical networks at the optical layer
There are many different forms of optical networks, from local area networks to the backbone networks of the Internet. Each network may tackle a particular threat type in a different manner. Researchers investigate the optical layer to examine whether there are any threats to privacy, availability, authentication, and secrecy (Skorin-Kapov, 2016).
A. Confidentiality
Even though optical networks don’t have an electromagnetic signature, an attacker may nonetheless listen in on them by physically tapping into the optical fiber or by pretending as a lawful subscriber and listening to residual crosstalk from an adjacent channel. It is not hard to tap an
The document is a seminar report on secure communication over fiber optic networks submitted by Fiona Rozario. It discusses optical networks and various security issues in optical networks including issues in network transmission, optical amplifiers, and optical cross-connects. It then covers different encryption systems that can provide security in optical networks such as optical CDMA, quantum cryptography, chaos-based encryption, and optical steganography.
A collaborative physical layer security schemeIJECEIAES
High level of security is essential in wireless 5G communications. The last few years there has been an increase in research interest in the potential of the radio channel’s physical properties to provide communications security. These research efforts investigate fading, interference, and path diversity to develop security techniques for implementation in 5G New Radio (NR). In this paper, we propose a collaborative scheme to existing physical layer security schemes, taking advantage of the characteristics of the OFDM technique. An OFDM symbol includes the pilot subcarriers, typically essential for the pilot channel estimation process performed at the legitimate receiver. In this work we propose the positions of the subcarriers to change on every OFDM symbol following a probability distribution known only to the legitimate transmitter and legitimate receiver. An eavesdropper, does not have access to the information of the pilot subcarriers positions so, it performs blind channel estimation. The theoretical analysis is based on the information theoretic problem formulation and is confirmed by simulations. The performance metrics used are the secrecy capacity and the outage probability. The proposed scheme is very simple and robust, strengthening security in multimedia applications.
Reliable and Efficient Data Acquisition in Wireless Sensor NetworkIJMTST Journal
The sensors in the WSN sense the surrounding, collects the data and transfers the data to the sink node. It
has been observed that the sensor nodes are deactivated or damaged when exposed to certain radiations or
due to energy problems. This damage leads to the temporary isolation of the nodes from the network which
results in the formation of the holes. These holes are dynamic in nature and can grow and shrink depending
upon the factors causing the damage to the sensor nodes. So a solution has been presented in the base paper
where the dual mode i.e. Radio frequency and the Acoustic mode are considered so that the data can be
transferred easily. Based on this a survey has been done where several factors are studied so that the
performance of the system can be increased.
THE UWB SOLUTION FOR MULTIMEDIA TRAFFIC IN WIRELESS SENSOR NETWORKSijwmn
Several researches are focused on the QoS (Quality of Service) and Energy consumption in wireless Multimedia Sensor Networks. Those research projects invest in theory and practice in order to extend the spectrum of use of norms, standards and technologies which are emerged in wireless communications.
The performance of these technologies is strongly related to domains of use and limitations of their characteristics. In this paper, we give a comparison of ZigBee technology, most widely used in sensor networks, and UWB (Ultra Wide Band) which presents itself as competitor that present in these work better results for audiovisual applications with medium-range and high throughput.
REAL TIME SECURING OF ALL-OPTICAL NETWORKS AGAINST SECURITY ATTACKS AT THE PH...IJNSA Journal
The document describes protocols for securing all-optical networks against physical layer security attacks. It proposes:
1. Calculating security indices for network components and storing them in databases at source nodes. This is used to establish secure lightpaths avoiding attacked components.
2. Establishing lightpaths using fiber diversity between nodes for redundancy against fiber attacks.
3. Monitoring components for attacks during data transfer. Attacked components are partially restored on-the-fly to minimize data loss instead of tearing down lightpaths.
REAL TIME SECURING OF ALL-OPTICAL NETWORKS AGAINST SECURITY ATTACKS AT THE PH...IJNSA Journal
This paper deals with protecting all-optical networks (AON) from security attacks at the physical level. It firstly presents an overall high level protocol for establishment, management and on-the-fly restoration of optimal secure lightpaths established by applying constraint-based open shortest path first (OSPF) source routing using proposed security databases of components. Secondly it presents a protocol for using fiber diversity between adjacent nodes to protect against attacks on fiber links. Thirdly it presents analytical models of propagation of security attacks on optical amplifiers and switches. These models are then used to develop security envelopes around these components, to calculate security indices and on-the-fly real-time restoration of components in case of an attack. Fourthly it presents simulation results for evaluation of the performance of these on-the-fly restoration schemes. These on-the-fly restoration schemes eliminate need for tearing down of attacked lightpaths and prevent consequent loss of large amount of data.
This document summarizes a seminar presentation on Optical Code Division Multiple Access (OCDMA). OCDMA allows multiple users to transmit simultaneously over the same bandwidth using unique optical codes. It provides advantages over TDMA and FDMA such as supporting more users and asynchronous transmission without packet collisions. The presentation describes OCDMA network implementation using optical orthogonal codes assigned to transmitters and receivers for communication. It also discusses enhanced security provided by OCDMA through increasing the signal-to-noise ratio required for eavesdropping.
An Energy Efficient Data Secrecy Scheme For Wireless Body Sensor NetworksCSEIJJournal
Data secrecy is one of the key concerns for wireless body sensor networks (WBSNs). Usually, a data
secrecy scheme should accomplish two tasks: key establishment and encryption. WBSNs generally face
more serious limitations than general wireless networks in terms of energy supply. To address this, in this
paper, we propose an energy efficient data secrecy scheme for WBSNs. On one hand, the proposed key
establishment protocol integrates node IDs, seed value and nonce seamlessly for security, then
establishes a session key between two nodes based on one-way hash algorithm SHA-1. On the other hand,
a low-complexity threshold selective encryption technology is proposed. Also, we design a security
selection patter exchange method with low-complexity for the threshold selection encryption. Then, we
evaluate the energy consumption of the proposed scheme. Our scheme shows the great advantage over
the other existing schemes in terms of low energy consumption.
SR-Code: Smart Relay Network Coding for Data Collection for Wireless Sensor N...IJERA Editor
Reliability in data collection for wireless sensor networks is one of the major problems in IoT applications. Sensor nodes are usually placed in harsh conditions where data communication is at risk of losing packets. Retransmissions are considered costly in terms of delay and power consumptions, especially that wireless sensor nodes are battery operated. In this context we introduce SR-Code, a novel network coding algorithm that achieves reliability in harsh conditions. SR-Code utilizes the XOR operator to code overheard packets. The targeted network topology is a 2-tier network where data loss can occur in all tiers. SR-Code utilizes bit addresses where each node is identified by a single bit in an address bit vector. Identifying packets and computing the cardinality of coded messages can be easily done using address bit vectors. SR-Code realizes redundancy as a function of overheard packet. SR-Code achieved a reliability factor of 75% when the number of packets lost was 100% of the original (un-coded) packet sent.
Optimised wireless network using smart mobile terminal antenna SMTA system marwaeng
1) The document presents a novel smart mobile terminal antenna system (SMTA) that uses a switched radiation beam approach to optimize wireless network performance, security, and signal tracking.
2) A key innovation is the dielectrically embedded SMTA (DE-SMTA) that reduces the antenna volume by 80% through embedding in a ceramic material. Testing showed the DE-SMTA maintained consistently high wireless signal levels compared to a fixed beam approach.
3) The SMTA system software performs scans to select the optimal radiation beam every 10 seconds to adapt to the dynamic wireless environment, improving network performance and security by directing signals toward the intended receiver.
Wireless Sensor Network Based Clustering Architecture for Cooperative Communi...ijtsrd
1. The document proposes a cluster-based cooperative communication architecture for wireless sensor networks. It uses clustering as an underlying system to help with stable routing and cooperative transmission.
2. The architecture has three components: an underlying clustering structure, cluster-based cooperative transmission, and analysis of cooperative transmission opportunities.
3. It evaluates the proposed cooperative transmission approach through simulation and finds it achieves at least 12 times higher energy efficiency than non-cooperative transmission.
This document provides a literature review of various methods proposed by researchers to improve energy efficiency and security in wireless sensor networks (WSNs). It summarizes several key energy efficient routing protocols like LEACH, PEGASIS and TEEN, as well as security threats like denial of service attacks, wormhole attacks, and Sybil attacks. The document reviews several studies that have developed algorithms and schemes to reduce energy consumption through techniques like dynamic clustering, mobile agent clustering, and randomized routing. It also discusses schemes to prevent security issues like false data injection and improve data authentication. The conclusion states that future work needs to focus on improving battery power and providing better fault tolerance and protection from severe security threats in WSNs.
Energy Proficient and Security Protocol for WSN: A Reviewtheijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Theoretical work submitted to the Journal should be original in its motivation or modeling structure. Empirical analysis should be based on a theoretical framework and should be capable of replication. It is expected that all materials required for replication (including computer programs and data sets) should be available upon request to the authors.
The International Journal of Engineering & Science would take much care in making your article published without much delay with your kind cooperation
Security Method in Data Acquisition Wireless Sensor Network Dharmendrasingh417
This document discusses security methods for data acquisition in wireless sensor networks. It first introduces wireless sensor networks and some of their challenges, including security issues. It then outlines the objectives of exploring routing algorithms and an intrusion prevention system to authenticate nodes and ensure data integrity and confidentiality. The document describes the proposed system of sensor nodes communicating with router pairs running dual routing algorithms and an intrusion prevention system to filter unauthorized data packets. It presents some experimental results on security and power consumption and concludes that the existing system focuses on self-powered routing but more research is still needed on secure and energy-efficient solutions.
IRJET- Under Water Optical Wireless CommunicationIRJET Journal
This document discusses underwater optical wireless communication (UWOC). It begins with an abstract that outlines the challenges of UWOC such as attenuation, scattering, and turbulence. It then provides an introduction to different modulation techniques used in UWOC like on-off keying, digital pulse interval modulation, and polarized digital pulse interval modulation. The rest of the document describes a simulation of a UWOC link using different parameters like bit rate, distance, power, and wavelength. It analyzes the impact of distance on the quality factor and bit error rate. The conclusion is that increasing distance leads to more signal distortion and lower quality communication.
FUTURE TRENDS IN FIBER OPTICS COMMUNICATIONIJCI JOURNAL
This document discusses future trends in fiber optic communication. It begins with an introduction to fiber optic communication and how advances in technology have increased data transmission capacity through optical fibers. The document then discusses several potential future trends, including all optical communication networks that process data entirely in the optical domain, multi-terabit optical networks enabled by dense wavelength division multiplexing, and intelligent optical transmission networks that can dynamically allocate resources. Overall, the document outlines how fiber optic communication is expected to continue advancing to support higher data rates, more advanced switching techniques, and smarter network architectures.
A Review of Physical, Data and Network Layer Specification and its Protocols ...Editor IJMTER
Wireless sensor network is a group of smart sensors, each capable of sensing, processing and
communicating the data or messages when any event occurs. When nodes deployed in numbers it form a
network which collectively monitor the state of the phenomenon activity of physical world. Its applications and
potential benefits are remarkable and seem only limited by imagination. The interdisciplinary property makes
the challenges wide and deep for design network protocols, efficient power utilization, programming models
and application areas. This survey paper focuses on the basic of WSN technology and its design factors. It also
focuses on the physical layer issues, data link layer protocols and its services and protocols used in layers.
This document discusses two schemes for implementing multirate transmission in fiber-optic code-division multiple access (CDMA) networks: the parallel scheme and the serial mapping scheme. The parallel scheme assigns each user multiple addresses based on their data rate and encodes bits in parallel. The serial mapping scheme encodes bits serially using optical orthogonal codes (OOCs) constructed from frequency hop codes. Analysis shows the parallel scheme can support error correction coding to increase network capacity, while the serial mapping performs well even without coding. Both schemes allow accommodating high numbers of multirate users without increasing optical processing complexity.
Optical network is an emerging technology for data communication
inworldwide. The information is transmitted from the source to destination
through the fiber optics. All optical network (AON) provides good
transmission transparency, good expandability, large bandwidth, lower bit
error rate (BER), and high processing speed. Link failure and node failure
haveconsistently occurred in the traditional methods. In order to overcome
the above mentioned issues, this paper proposes a robust software defined
switching enabled fault localization framework (SDSFLF) to monitor the
node and link failure in an AON. In this work, a novel faulty node
localization (FNL) algorithm is exploited to locate the faulty node. Then, the
software defined faulty link detection (SDFLD) algorithm that addresses the
problem of link failure. The failures are localized in multi traffic stream
(MTS) and multi agent system (MAS). Thus, the throughput is improved in
SDSFLF compared than other existing methods like traditional routing and
wavelength assignment (RWA), simulated annealing (SA) algorithm, attackaware RWA (A-RWA) convex, longest path first (LPF) ordering, and
biggest source-destination node degree (BND) ordering. The performance of
the proposed algorithm is evaluated in terms of network load, wavelength
utilization, packet loss rate, and burst loss rate. Hence, proposed SDSFLF
assures that high performance is achieved than other traditional techniques.
Similar to 9 Aab32 Dd Bdb9 137 E Ca2184 F057753212 154710 (20)
3 Simple Steps To Buy Verified Payoneer Account In 2024SEOSMMEARTH
Buy Verified Payoneer Account: Quick and Secure Way to Receive Payments
Buy Verified Payoneer Account With 100% secure documents, [ USA, UK, CA ]. Are you looking for a reliable and safe way to receive payments online? Then you need buy verified Payoneer account ! Payoneer is a global payment platform that allows businesses and individuals to send and receive money in over 200 countries.
If You Want To More Information just Contact Now:
Skype: SEOSMMEARTH
Telegram: @seosmmearth
Gmail: seosmmearth@gmail.com
The APCO Geopolitical Radar - Q3 2024 The Global Operating Environment for Bu...APCO
The Radar reflects input from APCO’s teams located around the world. It distils a host of interconnected events and trends into insights to inform operational and strategic decisions. Issues covered in this edition include:
Brian Fitzsimmons on the Business Strategy and Content Flywheel of Barstool S...Neil Horowitz
On episode 272 of the Digital and Social Media Sports Podcast, Neil chatted with Brian Fitzsimmons, Director of Licensing and Business Development for Barstool Sports.
What follows is a collection of snippets from the podcast. To hear the full interview and more, check out the podcast on all podcast platforms and at www.dsmsports.net
Part 2 Deep Dive: Navigating the 2024 Slowdownjeffkluth1
Introduction
The global retail industry has weathered numerous storms, with the financial crisis of 2008 serving as a poignant reminder of the sector's resilience and adaptability. However, as we navigate the complex landscape of 2024, retailers face a unique set of challenges that demand innovative strategies and a fundamental shift in mindset. This white paper contrasts the impact of the 2008 recession on the retail sector with the current headwinds retailers are grappling with, while offering a comprehensive roadmap for success in this new paradigm.
[To download this presentation, visit:
https://www.oeconsulting.com.sg/training-presentations]
This presentation is a curated compilation of PowerPoint diagrams and templates designed to illustrate 20 different digital transformation frameworks and models. These frameworks are based on recent industry trends and best practices, ensuring that the content remains relevant and up-to-date.
Key highlights include Microsoft's Digital Transformation Framework, which focuses on driving innovation and efficiency, and McKinsey's Ten Guiding Principles, which provide strategic insights for successful digital transformation. Additionally, Forrester's framework emphasizes enhancing customer experiences and modernizing IT infrastructure, while IDC's MaturityScape helps assess and develop organizational digital maturity. MIT's framework explores cutting-edge strategies for achieving digital success.
These materials are perfect for enhancing your business or classroom presentations, offering visual aids to supplement your insights. Please note that while comprehensive, these slides are intended as supplementary resources and may not be complete for standalone instructional purposes.
Frameworks/Models included:
Microsoft’s Digital Transformation Framework
McKinsey’s Ten Guiding Principles of Digital Transformation
Forrester’s Digital Transformation Framework
IDC’s Digital Transformation MaturityScape
MIT’s Digital Transformation Framework
Gartner’s Digital Transformation Framework
Accenture’s Digital Strategy & Enterprise Frameworks
Deloitte’s Digital Industrial Transformation Framework
Capgemini’s Digital Transformation Framework
PwC’s Digital Transformation Framework
Cisco’s Digital Transformation Framework
Cognizant’s Digital Transformation Framework
DXC Technology’s Digital Transformation Framework
The BCG Strategy Palette
McKinsey’s Digital Transformation Framework
Digital Transformation Compass
Four Levels of Digital Maturity
Design Thinking Framework
Business Model Canvas
Customer Journey Map
SATTA MATKA SATTA FAST RESULT KALYAN TOP MATKA RESULT KALYAN SATTA MATKA FAST RESULT MILAN RATAN RAJDHANI MAIN BAZAR MATKA FAST TIPS RESULT MATKA CHART JODI CHART PANEL CHART FREE FIX GAME SATTAMATKA ! MATKA MOBI SATTA 143 spboss.in TOP NO1 RESULT FULL RATE MATKA ONLINE GAME PLAY BY APP SPBOSS
Top mailing list providers in the USA.pptxJeremyPeirce1
Discover the top mailing list providers in the USA, offering targeted lists, segmentation, and analytics to optimize your marketing campaigns and drive engagement.
HOW TO START UP A COMPANY A STEP-BY-STEP GUIDE.pdf46adnanshahzad
How to Start Up a Company: A Step-by-Step Guide Starting a company is an exciting adventure that combines creativity, strategy, and hard work. It can seem overwhelming at first, but with the right guidance, anyone can transform a great idea into a successful business. Let's dive into how to start up a company, from the initial spark of an idea to securing funding and launching your startup.
Introduction
Have you ever dreamed of turning your innovative idea into a thriving business? Starting a company involves numerous steps and decisions, but don't worry—we're here to help. Whether you're exploring how to start a startup company or wondering how to start up a small business, this guide will walk you through the process, step by step.
Understanding User Needs and Satisfying ThemAggregage
https://www.productmanagementtoday.com/frs/26903918/understanding-user-needs-and-satisfying-them
We know we want to create products which our customers find to be valuable. Whether we label it as customer-centric or product-led depends on how long we've been doing product management. There are three challenges we face when doing this. The obvious challenge is figuring out what our users need; the non-obvious challenges are in creating a shared understanding of those needs and in sensing if what we're doing is meeting those needs.
In this webinar, we won't focus on the research methods for discovering user-needs. We will focus on synthesis of the needs we discover, communication and alignment tools, and how we operationalize addressing those needs.
Industry expert Scott Sehlhorst will:
• Introduce a taxonomy for user goals with real world examples
• Present the Onion Diagram, a tool for contextualizing task-level goals
• Illustrate how customer journey maps capture activity-level and task-level goals
• Demonstrate the best approach to selection and prioritization of user-goals to address
• Highlight the crucial benchmarks, observable changes, in ensuring fulfillment of customer needs
The Genesis of BriansClub.cm Famous Dark WEb PlatformSabaaSudozai
BriansClub.cm, a famous platform on the dark web, has become one of the most infamous carding marketplaces, specializing in the sale of stolen credit card data.
Best practices for project execution and deliveryCLIVE MINCHIN
A select set of project management best practices to keep your project on-track, on-cost and aligned to scope. Many firms have don't have the necessary skills, diligence, methods and oversight of their projects; this leads to slippage, higher costs and longer timeframes. Often firms have a history of projects that simply failed to move the needle. These best practices will help your firm avoid these pitfalls but they require fortitude to apply.
At Techbox Square, in Singapore, we're not just creative web designers and developers, we're the driving force behind your brand identity. Contact us today.
Company Valuation webinar series - Tuesday, 4 June 2024FelixPerez547899
This session provided an update as to the latest valuation data in the UK and then delved into a discussion on the upcoming election and the impacts on valuation. We finished, as always with a Q&A
Discover timeless style with the 2022 Vintage Roman Numerals Men's Ring. Crafted from premium stainless steel, this 6mm wide ring embodies elegance and durability. Perfect as a gift, it seamlessly blends classic Roman numeral detailing with modern sophistication, making it an ideal accessory for any occasion.
https://rb.gy/usj1a2
2. of physical layer encryption have attracted significant attention in recent years. One is based
on the synchronization of two lasers operating in a chaotic regime [1],[2]. The other is based
on optical code division multiple access (CDMA) [3],[4]. Each of these methods has its
strengths and weaknesses. The chaotic laser scheme is fundamentally limited in data rate
owing to the inherent time constants dictating laser dynamics. It typically has a small number
of user adjustable parameters (low soft-key dimension) such that security relies almost
entirely on the inability of an eavesdropper to obtain similar laser hardware (i.e. on the hard-
key). Logistically, this can be a disadvantage, as security is controlled by the optical hardware
manufacturer much more than it is controlled by the user. In the case of optical CDMA there
are issues with the coexistence of multiple users and in some implementations, the
simultaneous presence of many users is a prerequisite for secure transmission. In both of the
above schemes the overall quality of communications is usually lower than what it could be in
well optimized, conventional, unencrypted system case.
In this work we propose and characterize an alternative scheme for secure optical
communications. With this scheme Alice and Bob receive identical replicas of a truly random
broadband optical signal from which they both extract identical random binary sequences that
they use as a secret key for encrypting and decrypting information. This scheme takes after
the classic running-key cipher, in which a text, typically from a book, is used to provide a
very long keystream [5]. The secrecy of the key established by Alice and Bob is provided by
identical optical scramblers whose physical structure and parameter settings are not known to
Eve. The proposed scheme has a number of attractive features; there is no fundamental limit
to the data-rate, implying that encrypted transmission can be conducted at the usual rates of
fiber optic systems. The number of adjustable parameters used as a soft-key in the
transmission can in principle be made as large as desired, thereby conveniently dividing the
responsibility for the reliability of encryption between the hardware manufacturer and the
user. Thirdly, and perhaps most importantly, integration of the proposed method with existing
communication systems is relatively simple, it is modulation format independent and it does
not fundamentally impair the overall performance of the optical communication link.
The proposed scheme and its principle of operation are described in Section 2. Section 3
describes practical consideration details and section 4 presents the specific implementation of
the key-establishment scheme whose performance is evaluated in section 5. Section 6 is
devoted to a discussion and conclusions.
2. Principle of operation
A schematic description of the principle of operation of the proposed method is shown in Fig.
1. The communicating parties, Alice and Bob, receive identical copies of a truly random
broadband optical signal, from which they extract a random binary sequence to be used as key
for encrypted communication using the one-time pad protocol. The broadband random optical
signal is obtained from the amplified spontaneous emission of an optical amplifier that is
distributed to the users. Since the scheme is intended for use in wavelength division
multiplexed (WDM) networks, a filter appropriately limiting the bandwidth of the random
optical signal, is assumed to be present at the amplifier output. The random binary key
sequence is established after both Bob and Alice photo-detect the optical signal, sample it
after low-pass electrical filtering and compare the samples to a threshold. A sample that is
greater than the threshold is registered as a logical one and a sample lower than the threshold
is registered as a logical zero. Assuming that the clocks of both parties are properly
synchronized and the absence of noise, the random binary sequences obtained by Alice and
Bob will be identical. In fact, the structure and all components of the receivers are standard in
fiber-optic communications. Identical optical scramblers are used by the communicating
parties, prior to photo-detection, in order for the random key sequence not to be accessible to
an eavesdropper.
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3384
3. Fig. 1. Illustration of the principle of operation showing the structure of the key-establishment
receiver. the electrical low-pass filter (E-LPF) is not plotted explicitly but it is assumed to be
part of the photo-detection unit. For simplicity the figure relates only to the key establishment
part of the system and to a single pair of users. In practice the random signal can be distributed
among many pairs of WDM users. The spectrum in the WDM case is illustrated as well.
While the scrambler can be based on a variety of technologies, including the ones currently
used for optical scrambling in CDMA [4], we consider a simple scrambler structure that is
based on commercially available devices used for tunable optical dispersion compensation.
These scramblers consist of a concatenation of several highly dispersive optical filters whose
transfer functions can be controlled dynamically and that introduce long-lived distortions to
the incident broadband optical signal in the time domain. The adjustable parameters of the
scramblers constitute the soft-key. A detailed description of the scramblers in our particular
implementation will be provided in section 4.1. At Alice's transmitter, the established key is
XOR multiplied with the original message (plaintext) thereby producing the encrypted
message (the ciphertext). After XOR multiplying the ciphertext with the established key at the
receiver, the plaintext is recovered by Bob.
The above described scheme can be readily deployed in a WDM setting where the same
broadband signal is distributed among multiple pairs of users sharing the same fiber.
3. Practical considerations
3.1 The use of two threshold levels, synchronization and the effective rate factor
In a realistic scenario, the assumptions of ideality regarding the identity of the two scramblers
and the absence of noise are clearly invalid. Under practical operating conditions, the above
described key establishment scheme is likely to produce errors whenever the value of the
detected sample is close to the threshold level, such that even a very small perturbation may
cause Alice and Bob to register their bits differently. In order to avoid such situations, two
threshold levels are introduced instead of one; a lower threshold below which the symbol is
identified as a quot;zeroquot; and a higher threshold above which the symbol is identified as a quot;onequot;.
When the detected sample falls between the two thresholds, the symbol identity is declared as
quot;don't carequot;. Alice and Bob must then communicate with each other in order to disclose the
positions of the quot;don't carequot; symbols, such that the final key consists of all shared symbols
except for those that have been identified by one of the parties as quot;don’t carequot;. The presence
of quot;don't carequot; symbols reduces the effective key-establishment rate and requires that the
clock rate used for key establishment is higher than the data-rate of the cipher-text, if the one-
time-pad protocol is to be used. We show in the next section that the increase in the clock-rate
that is needed for reliable operation is fairly reasonable and not unusual in optical
communications. In what follows we often refer to the effective rate factor which we define ρ
as the average fraction of “legal” results (i.e. ones and zeros) within the detected samples (that
include zeros, ones and don’t cares). i.e. ρ = 1− Prob(don' t care) . This quantity represents the
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3385
4. rate reduction resulting from the use of two thresholds. In order to maintain the highest
security, disclosure of the positions of the don't care symbols should be performed over the
encrypted channel. Only at the stage of system initiation quot;don't carequot; positions are shared
without encryption until a sufficiently long buffer of key symbols is established. A possible
variation on the above described protocol is to have only Alice disclose her “don’t care”
positions to Bob. In this case, whenever Bob identifies a “don’t care” that was not in Alice’s
list, he attaches to it a value of logical zero or one based on whether the detected sample was
closer to the lower, or upper threshold, respectively. This modification slightly increases the
effective key-establishment rate (as there are less declared “don’t care” symbols), but also
increases by very little the error probability. As the overall effect of this modification is small,
we will not include it in what follows.
The issue of synchronization also deserves some consideration. Since there is no inherent
clock in the random broadband optical signal, a clock signal must be distributed between
Alice and Bob separately. A convenient approach for synchronization would be to scale up the
clock signal that is extracted by the users from the binary ciphertext so that it matches the
sample rate used in key generation.
3.2 Forward error-correction and privacy amplification
An important parameter in the characterization of the scheme is the bit-error-rate (BER).
When used with respect to Alice and Bob, this term is defined as the fraction of symbols that
they detect differently (after removing the symbols that have been identified by either one of
them as “don’t care”). When the BER is mentioned with respect to Eve, it is defined as the
fraction of symbols that Eve identifies differently from Alice and Bob. Proper operation
requires that Alice and Bob's BER remains close to zero, whereas Eve's BER is as close as
possible to 0.5, implying that the sequence that she acquires has no correlation with the
original data. In order to achieve this situation in practice, one needs to apply privacy
amplification algorithms such as the ones implemented for quantum key distribution schemes
[6], in conjunction with forward error-correction (FEC) codes [7]. With privacy amplification,
Alice passes the plaintext through a privacy amplification encoder prior to encrypting it and
sending it to Bob. Bob decrypts the received message and then passes it through a privacy
amplification decoder. If no errors occurred in the process of transmission, or decryption in
Bob's receiver, the message that he will recover after the privacy amplification decoder will be
identical to the message sent by Alice originally. On the other hand, if Eve's received and
decrypted message contains errors (even few errors), the sequence that she obtains after the
privacy amplification decoder will be practically uncorrelated with Alice's original sequence,
thereby giving her absolutely no information about the transmitted data. The role of FEC
coding is to introduce some tolerance to errors between Alice and Bob. Such codes have the
ability to eliminate errors in a received block of data, as long as their number is smaller than
some value called the FEC threshold [7]. When it is greater than the threshold, the number of
errors remains unchanged on average. Thus, as long as the BER between Alice and Bob
remains lower than the FEC threshold, and Eve's BER is higher than the FEC threshold, Bob
will receive an error-free message while Eve's recovered sequence will be practically
uncorrelated with the original data. The higher the FEC threshold (i.e. the stronger the FEC
code [7]) the more tolerant the scheme becomes to differences between Bob's and Alice's
received signals, but at the same time resistance to eavesdropping becomes lower. The
optimal FEC threshold is therefore an application specific parameter that depends on the
amount of noise present in the communication process and on the required security. As a
figure of merit, the strongest FEC codes used in optical communications today have a 7%
overhead and their FEC threshold can be as low 10-3 [8].
4. Specific implementation
The specific implementation that we assumed in the numerical evaluation is described
schematically in Fig. 2. The dashed lines represent electrical wiring whereas solid lines
represent optical fibers. Since encryption and decryption are performed digitally, by XOR
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3386
5. multiplying the plaintext with the established key, the optical data transmitter and receiver
indicated in the figure are standard elements in digital optical communications. The most
critical devices in the proposed scheme are the scramblers, the random signal source and the
receiver used for key generation.
y
e
K
Fig. 2. The proposed set-up for secure communications
4.1 The optical scrambler
In the following we consider a specific scrambling device that is based on Gires Tournois
(GT) etalons [9]. The configuration of the GT etalon is illustrated in the inset of Fig. 3. This
device is essentially a Fabry Perot interferometer operating in reflection. It has a perfectly
reflecting back mirror and a partially reflecting front mirror whose reflection coefficient is
denoted by r. The roundtrip time through the device is T = 2 L / nc with L being the device
thickness and with n and c denoting the refractive index inside the etalon and the speed of
light, respectively. The GT etalon is characterized by an infinite impulse response (IIR)
h (t ) = − rδ (t ) + (1 − r 2 )eiϕ [δ (t − T ) + reiϕ δ (t − 2T ) + r 2 e 2 iϕ δ (t − 3T ) + ], (1)
where ϕ is a frequency independent propagation phase. While the parameters r and T are fixed
in the manufacturing process, the phase ϕ can be varied by controlling the etalon
temperature. Thus, as is indicated by Eq. (1), the etalon generates a coherent superposition of
many delayed replicas of the incident optical signal with controllable coefficients. By
concatenating several GT etalons, where each can be characterized by a unique reflectivity
and roundtrip delay, a more complicated superposition of delayed replicas follows, thereby
generating the desired scrambling operation. A scrambler with N etalons has 2N fixed degrees
of freedom (the quot;hard-keyquot;) and N variable degrees of freedom that can be adjusted by the
user (the quot;soft keyquot;). The corresponding frequency response of a single etalon is conveniently
ω
expressed as H (ω ) = exp − i τ (ω ′)dω ′ , where τ (ω ) is the group delay spectrum
⎡ ⎤
⎢ ⎥
∫
−∞
⎣ ⎦
T (1 − r 2 )
τ (ω ) = (2)
1 − 2 r cos(ωT + ϕ ) + r 2
and where the frequency independent delay was omitted for simplicity. In Fig. 3 we plot the
group delay spectra of four etalons used in our study. The figure shows the spectra of the
individual etalons with different reflection coefficients and phases, whereas their sum (the
spectrum of the concatenated etalons) is illustrated by the dashed curve. The spectra are
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3387
6. periodic with a period (referred to as the free spectral range) equal to 1/T and the higher the
value of r, the more peaked the group delay spectrum becomes. For achieving efficient
scrambling, the fixed parameter values of the etalons should be selected according to the
following guidelines; The achievable delays must be sufficiently greater than the key
sampling period, but on the other hand, the characteristic width of the group delay spectrum
must have a significant enough overlap with the bandwidth of the random optical signal. As
we explain in what follows the FWHM bandwidth of the random optical signal that we use
was 80GHz, and thus etalons with T = 20ps and reflection coefficients of r = 0.3, 0.4, 0.5 and
0.6 were used. These parameters were also chosen because they fall in the range of easily
manufacturable values and because etalons with similar characteristics are used in commercial
devices for tunable dispersion compensation [10]. A relevant parameter for the operation of
the scrambler is the tuning time. This parameter depends on the particular scrambler assembly
technology and type of control circuitry used for temperature stabilization. The overall
stabilization time of the commercial tunable dispersion compensators built with this
technology is of the order of 20 seconds.
Combined
Perfect
160
delay
mirror
Group delay [ps]
r<1
120
80
r =0.4
40 r =0.5
r =0.3
r =0.6
0
-30 -20 -10 0 10 20 30
Relative frequency [GHz]
Fig. 3. The group delay spectra of 4 GT etalons with reflection coefficients of 0.3, 0.4, 0.5 and
0.6. The blue dashed curve represents the combined group delay spectrum of the scrambler.
The GT etalon is illustrated in the inset.
4.2 The random source and the optical receiver used for key generation
An amplifier generating spontaneous emission noise followed by an optical band-pass filter
serves as the source of the random signal. Its output is accurately modeled as a zero mean
Gaussian process in four dimensions; two quadratures and two polarizations. In Fig. 2,
displaying the setup that we used in the numerical evaluations, we arbitrarily positioned the
noise source inside of Alice's transmitter. The central wavelength of the random signal is
assumed to be in the conventional transmission band (C-band) of the optical fiber around
1550 nm. The optical bandwidth of the source must be greater than the key sampling-rate such
that its correlation time is sufficiently smaller than the time interval between samples. On the
other hand, an excessively large bandwidth of the random source is also undesirable, owing to
spectral efficiency implications when the scheme is used in a WDM setting. Additionally,
since the electrical bandwidth of the key-sampling receiver is finite, the indefinite increase of
the optical bandwidth has no benefit to security. For these reasons, and also in order to
facilitate the numerical evaluation we have chosen the bandwidth of the optical band-pass
filter following the amplifier source to be equal to 0.65nm (FWHM) while the key sampling
rate that we used was 40GSamples/s. The shape of the optical band-pass filter was modeled as
second order Gaussian. The photo-receiver's pass-band is modeled as a 3rd order Bessel filter
as is often done in the modeling of optical communication systems. Its width at half maximum
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3388
7. is assumed to be equal to 40GHz, consistent with available optical receiver technology. After
sampling the electrically filtered signal we chose the upper and the lower threshold levels
such that the average number of quot;onesquot; is identical to the average number of quot;zerosquot;. The
separation between the two thresholds is determined by the trade-off between the immunity
that one wishes to achieve from the effects of spurious noise, or imperfect matching between
Bob's and Alice’s hardware, and the reduction in the key-establishment rate that one is willing
to accept.
5. Performance evaluation
The scrambling effect of a single etalon can be observed in the simple illustration presented in
Fig. 4. The figure shows the relation between Bob’s BER and the alignment of the scrambler
parameters when three of the four etalons in Bob’s receiver are set correctly, whereas the
fourth etalon’s phase is offset. When the offset etalon is the one with the highest reflectivity (r
= 0.6), the BER increases rapidly with phase mismatch, but the BER never reaches the
maximum value of 0.5. That is because the highest reflectivity corresponds to the narrowest
group delay spectrum (see Fig. 3) and while it is characterized by the largest peak group
delay, its spectral overlap with the random optical signal is the smallest. In the case of the
lowest reflectivity, the group delay spectrum of the etalon is the broadest and there is a slower
increase in BER. Yet, as the spectral overlap with the random signal is largest, the maximum
BER value of 0.5 is reached.
0.5
0.4
0.3
BER
r =0.6
r = 0.5
0.2
r = 0.4
r = 0.3
0.1
0
-1 -0.5 0.5 1
0
(phase shift)/π
Fig. 4. Bob’s BER when the phase of one of the four etalons in his scrambler is offset relative
to the correct value.
Next we examine the process of key establishment in the presence of spurious noise
introducing differences between the signals received by the two parties. As we explained
earlier, we address this problem by introducing two threshold levels sl and sh (with sl<sh) such
that a “one” is declared when the detected signal sample S is greater than sh and a “zero” is
declared when S is lower than sl. Whenever the signal measured by either Alice or Bob falls
between these two thresholds, the symbol is declared as a “don’t care” and is not included in
the key that Alice and Bob establish. In appendix A we calculate the BER between Alice and
Bob and relate it to the effective rate factor ρ = 1− Prob(don' t care) . The calculation that we
perform assumes that the detection process is dominated by optical noise that results from
optical pre-amplification in the receivers, or from inline amplifiers. A similar and even
simpler calculation follows if thermal electronic noise that is generated in the detector
dominates. Figure 5 shows the raw BER as a function of the effective rate factor for three ρ
typical values of optical signal to noise ration (OSNR), defined as the ratio between the
power-density of the random broad-band signal used for key sharing and the power density of
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3389
8. the additive optical noise. Note that in practice, independent optical noise contributions may
be present in both Alice’s and Bob’s sides of the system. In that case the noise power in the
expression for the OSNR is the sum of the noise powers in Alice’s and Bob’s receivers. As
can be seen in the figure, the BER can be made as low as desired at the expense of a reduction
in the key establishment rate. In fact, for reasonable values of OSNR in the vicinity of 20dB,
the BER reaches values as low as 10-9 with in the vicinity of 0.7, which is a fairly reasonable
ρ
value from a practical standpoint. Recall also that proper operation is ensured as long as Bob's
BER is lower then the FEC threshold and that the commonly used FEC in optical
communications can have a threshold as low as 10-3 [8].
0
10
OSNR=1
5dB
-5
10 OS
NR
BER
=2
0d
B
-10
10
OS
NR
=2
5 dB
-15
10
1 0.9 0.8 0.7 0.6
The effective rate factor ρ
Fig. 5. Raw BER as a function of the effective rate factor . The traces correspond to three
ρ
typical values of optical signal to noise ratio (OSNR).
In our attempt to assess the security of the propose scheme, we focus on the scenario of a
brute force attack by Eve, who tries to guess the correct setting of the scrambler parameters.
While this is the most basic and essential step in characterizing the scheme security, it is not
the only one, as more sophisticated attacks by an eavesdropper are possible [4]. Nevertheless,
in this paper we concentrate primarily on the introduction and description of the proposed
physical encryption concept. A rigorous analysis of system security in a broader sense will
therefore be left for a future study.
0 0
10 10
Cumulative Probability
Cumulative Probability
(a) (b)
lon
1 GT eta
-1 -1
10 10
ρ = 0.7
ρ=1 2
-2 -2 4
10 10
ρ = 0.5
8
ρ = 0.85
-3 -3
10 10
-2 -1 0 -2 -1
10 10 10 10 10
BER BER
Fig. 6. The vertical axis represents the probability that Eve attains a BER value indicated by the
horizontal axis when she guesses the soft-key parameters. (a) for several values of ρ and with 4
GT etalons (b) for ρ = 0.7 and with the number of GT etalons being 1, 2, 4 and 8.
We will assume that Eve is able to gain access to the correct scrambler hardware and that she
is trying to randomly guess the scrambler parameters in order to intercept the key established
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3390
9. between Alice and Bob. Notice that with the proposed scheme Alice does not have a useful
analog feedback signal to tell her how to change the setting of her scrambler. This is in
contrast to the cases of CDMA and chaotic laser encryption, where upon approaching the
correct soft-key parameters a clearly identifiable pulse-like optical waveform is gradually
unveiled. Moreover, for Eve's brute force attack to be meaningful, she must have some
knowledge about the transmitted plaintext. Her strategy would then be to mimic Bob's
receiver with randomly picked scrambler parameters, apply the resulting key sequence to the
ciphertext and see if what she obtains makes sense. As long as the fraction of errors in Eve's
key is higher than the FEC threshold, the privacy amplification algorithm will ensure that the
deciphered message is uncorrelated with the correct plaintext and Eve will have to start the
entire process over again and again. The highest FEC threshold available with existing FEC
technologies in optical communications is of the order of 10-3 [8], but weaker FEC's with a
lower threshold are also commercially available. The choice of FEC threshold is a trade-off
between the security of the scheme and its resilience to perturbations between the
communicating parties. The desirable measure of security against a brute force attack would
therefore be the probability that Eve can obtain a key with a lower BER than the FEC
threshold by guessing the scrambler parameters. Unfortunately, the numerical evaluation of
probabilities of achieving BER levels of 10-3, or lower, requires unrealistically long
computation times. Nevertheless, some insight can be gained from observing the probabilities
of guessing higher BER values. The results of a Monte Carlo simulation performed with the
proposed set-up are illustrated in Fig. 6(a). The horizontal axis in the figure represents the
BER, whereas the vertical axis shows the probability of achieving this, or higher BER level by
guessing the parameters blindly. The various curves correspond to different choices of the
distance between the two thresholds and they are labeled by the effective rate factor. As is
evident in the figure, and as one may intuitively expect, there is a trade-off between the
security of the system and its resilience to noise. It is also evident that achieving relevant BER
values would require Eve to perform a very large number of attempts. Taking into account the
slow time constants associated with the thermal control of the scrambler parameters, and
recalling that Alice and Bob will typically change the key periodically in order to increase
security, the prospects of a brute-force attack seem unrealistic. Further increase in security can
obviously be implemented by increasing the number of GT etalons in the optical scramblers.
An idea of the dependence of security on the number of etalons can be obtained from Fig. 6
(b). The axes in this figure are identical to those of Fig. 6(a), but the curves were obtained
with =0.7 and for a varying number of GT etalons in the scrambler. In the case of a single
ρ
etalon we used a reflectivity of 0.4, in the case of 2 etalons the reflectivity coefficients were
0.4 and 0.6, in the case of 4 etalons we used the same reflectivity values as in Fig. 6(a) (i.e.
0.3, 0.4, 0.5 and 0.6) and in the case of 8 etalons we used the same reflectivity values twice.
While the choice of reflectivity values in each case was made in order to achieve good
performance, it was not crucial. We preferred not to use a fixed reflectivity value many times
because this would introduce a redundancy that would help Eve, as the various etalons could
then compensate for one another. The strong dependence of security on the dimension of the
soft-key is evident from the figure.
An important factor in the applicability of the proposed scheme is its tolerance to link
parameters; primarily, to imperfections in the compensation for chromatic dispersion and to
PMD. As we focus on the linear regime of transmission, valid with current optical systems to
many hundreds of kilometers, parameters related to fiber nonlinearities will not be considered.
Fig. 7(a) illustrates Bob's BER, obtained in a Monte-Carlo simulation, as a function of the
uncompensated dispersion in Bob's link. The sign of dispersion (whether it is under, or over-
compensated) is immaterial and we therefore consider dispersion values between 0 and 50
ps/nm. Evidently the tolerance to dispersion is fairly low, and recalling that the FEC threshold
can be as high as 10-3, the allowed amount of uncompensated dispersion is of the order of
10ps/nm. While this is perhaps a relatively strict requirement, it is not inconsistent with the
capabilities of dispersion compensating devices in use today [11]. This requirement can be
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3391
10. alleviated somewhat if the effective rate factor is reduced to ρ = 0.5, as is shown by the
dashed curve in the figure.
-1
(a) (b)
10
-2
10
-2
10
BER
-3
10
-3
10
0.5 0.5
-4
10
0.7 0.7
-4
10
2 3 4 5
10 20 30 40 50
Dispersion [ps/nm] DGD [ps]
Fig. 7. (a) The BER as a function of uncompensated dispersion in Bob's receiver (b) The BER
as a function of uncompensated differential group delay (DGD) in Bob's receiver
The tolerance to PMD is examined in Fig. 7 (b), where the BER is computed in a range of
DGD values. For simplicity, we have assumed only first order PMD in the computations.
Notice that with ρ = 0.7, only as little as approximately 2.5 ps of PMD can be tolerated by the
system without the BER exceeding the dangerous level of 10-3, constituting a fairly significant
limitation. The situation is again alleviated somewhat when ρ = 0.5, and the allowed DGD
increases to approximately 3.5 ps. While remaining a significant limiting factor in practical
links, with the low PMD of modern fibers and components, the above restriction still allows
proper operation of the system over several hundreds of kilometers length.
One of the main advantages of the proposed scheme is the possibility of using standard,
off-the-shelf optical hardware for its implementation. The most significant element in the
system is the optical scrambler. For Alice and Bob to be able to communicate reliably, their
optical scramblers need to be as close to identical as possible. As an example of an off-the-
shelf optical device that is suitable for our purpose, we acquired two units of commercially
available, tunable optical dispersion compensators (TODC) by Civcom. Those devices are
based on four GT etalons with a free spectral range of 50GHz, as they were designed for a
multi-channel communication environment based on the ITU grid. The resonance frequencies
of the four individual etalons are independently controllable. We measured the group delay
and the insertion loss spectra of the two devices while setting the control parameters to
arbitrary, but identical values. An example of a group delay spectrum that we measured with
the two devices is shown in Fig. 6(a). We then used the measured spectra in our simulation to
calculate the expected raw BER as a function of the effective rate factor . The resemblance ρ
between the group delays of the two devices is fairly good, but not perfect. Fig. 8(b) shows
the raw BER that is obtained with these two devices after setting them to the same parameters,
as a function of . Notice that from comparison between Fig. 5 and Fig 8(b), the difference
ρ
between the spectra of the two devices is equivalent to the effect of noise at an OSNR level
close to 20dB. Once again, any desirable BER level can be achieved at the expense of a
corresponding reduction in the effective rate factor. Note that the tested TODC devices were
not designed for our purpose and no special emphasis was placed on ensuring similarity
between their spectra. Nevertheless, Fig. 8 suggests that the implementation of the proposed
scheme with readily available optical hardware should indeed be possible.
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3392
11. -1
10
300
(a) (b)
Group Delay [ps]
-2
10
200
BER
-3
10
-4
10
100
-5
10
1 0.6
-50 0 50 0.9 0.8 0.7
The effective rate factor ρ
Relative frequency [GHz]
Fig. 8. (a) The measured group delay spectrum of two commercial tunable dispersion
compensation devices by CIVCOM. Each device is implemented with four GT etalons. The
etalon temperatures in the two devices were set to four identical, but arbitrary values. (b) The
computed raw BER of a system that uses the two measured spectra, as a function of the
effective rate factor.
6. Discussion
We propose a new scheme for encryption that is based on the implementation of the one-time
pad protocol. The key that is used for the one-time pad is generated by each pair of users from
a truly random optical noise signal that is distributed among them. Each such pair of users
establishes a unique secret key by sampling the random optical signal that is distributed
between them after passing it through matching optical scramblers whose parameters are
tuned to identical values known only to that pair of users. The proposed scheme has a number
of attractive attributes that are advantageous when comparing to other existing methods of
encryption in the optical layer. The most important advantage is perhaps the fact that the it can
be designed into any method of digital optical communications, without affecting its
properties such as modulation format, pulse-shape, bandwidth etc. Hence it does not interfere
with the overall communication system performance. Although our analysis related only to
the case of a single pair of users, the scheme is compatible with WDM transmission with the
loss in the overall spectral efficiency being minimal. The unique method by which the key is
distributed prevents certain eavesdropping attacks to which other optical encryption schemes
are susceptible. In particular, the advantage is that neither the random waveform emanating
from the optical scrambler, nor the digital key extracted from it, display any distinct
characteristics to indicate when the scrambler parameters approach the correct values. In fact,
the only way that the eavesdropper can tell that he has found the correct scrambler setting is
by using the key that he obtains with the guessed setting in order to decrypt the ciphertext and
see whether the output sequence is intelligible to him. Thus, the security of the scheme can be
easily enhanced by applying any form of digital encryption to the original data. The
complexity of intercepting the original data in this case will be the product of the complexities
that would be needed in order to intercept the data if only one of the encryption methods
(either digital, or the proposed physical method) is used. This is contrary to the cases of
optical CDMA, or chaotic synchronization where the complexities would simply add to each
other since the interception of the physical layer code can be performed independently of the
digital encryption of the data. Our analysis and evaluation of the proposed scheme assumed
that a commercially available tunable optical dispersion compensation device is used as the
scrambler. We acquired a pair of such devices and tested their applicability to our scheme by
performing the evaluation with their measured spectra. A specific optimization of such
devices for use as scramblers, would emphasize their uniformity within the manufacturing
process and further improve their performance. Finally, although throughout this manuscript,
the key-sampling rate was assumed to be fixed at 40G samples per second, implementation of
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3393
12. the scheme with higher sampling rates is straightforward, provided only that optical receivers
with a correspondingly higher electrical bandwidth are available.
7. Appendix
In this appendix, we calculate the BER between Alice and Bob and relate it to the effective
rate factor which we have defined as the average fraction of “legal” results (i.e. ones and
ρ
zeros) within the detected samples (that include zeros, ones and don’t cares). In order to
reduce the complexity of notation, we initially perform the calculation for the case of scalar
fields. The final results are, as we comment later, unchanged when the signal and noise are
treated as unpolarized thermal radiation fields. Let E ( t ) denote the wide-band optical field
produced by Alice and let n ( t ) denote the additive noise in the channel. Since we have
assumed that the detection process is dominated by optical noise that results from optical pre-
amplification in the receivers, or from inline amplifiers, we model E ( t ) and n ( t ) as
statistically independent circular Gaussian noise processes, of the same optical bandwidth B
that is determined by the optical filter at the receivers. Alice's detector is subjected to the
signal E ( t ) whereas Bob's detector receives E ( t ) + n ( t ) . The electronic signals generated by
Alice's and Bob's detectors are proportional to
sA ( t ) = E ( t )
2
(A.1)
and
sB ( t ) = E ( t ) + n ( t )
2
(A.2)
respectively. Alice's receiver decides upon the identity of a symbol according to the electronic
signal S A that is generated by the photo-detector and filtered by the electrical low pass filter
(LPF) of the receiver:
h (τ ) s A (τ ) dτ ,
SA = (A.3)
∫
where h ( t ) is the impulse response of the LPF. In a similar manner, on Bob's side the
electronic signal is:
h (τ ) sB (τ ) dτ .
SB = (A.4)
∫
For reasonable values of SNR, one can approximate sB (t ) = E (t ) + 2 Re[E (t )n * (t )] . In this
2
case, SB can be expressed in terms of SA and an additive noise component, N,
SB = S A + N , (A.5)
where
h (τ ) E (τ ) n* (τ ) dτ .
N ≡ 2 Re (A.6)
∫
If we condition on the value of the field E, then N is a zero mean Gaussian variable whose
variance is
Var ( N | E ) = 2 N 0 h (τ ) s A (τ ) dτ ,
2
(A.7)
∫
where N0 is defined through
n ( t ) n* ( t ' ) = N 0δ ( t − t ' ) . (A.8)
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3394
13. The error probability is composed from the probabilities of two events: Either Alice decides
'1' and Bob decides '0', or the other way around. The BER therefore takes the following form:
P ( N > sh − S A | S A ) f ( S A ) dS A
sl
⎡ ⎤
P ( ε ) = 0.5
∫⎢
=
0 ⎥
∞
P ( N < sl − S A | S A ) f ( S A ) dS A
+
⎢ ⎥
∫⎢ ⎥
sh
,
⎣ ⎦
sh − S A (A.9)
f ( S A ) dS A
sl
⎡ ⎤
⎛ ⎞
Q
∫⎢ ⎥
⎜ ⎟
VAR( N | E )
0
⎢ ⎥
⎝ ⎠
0.5
S A − sl
⎢ ⎥
∞
f ( S A ) dS A
⎛ ⎞
+ Q
⎢ ⎥
⎜ ⎟
∫⎢
VAR( N | E )
sh ⎥
⎝ ⎠
⎣ ⎦
If we assume for simplicity an integrate and dump receiver, the impulse response of the
LPF is square and VAR( N | E ) = 2 N 0 S A . Assuming also a square optical filter, the distribution
of S A is χ 2 with M degrees of freedom, i.e.
SA
M −1 − 2σ 2
1
⎧
for S A > 0
2
SA e E
( 2)
,
( 2σ )
⎪
fS ( SA ) =
M
⎪
ΓM
2
(A.10)
2
⎨ E
⎪
for S A ≤ 0
0
⎪
⎩
where M=2BT, with T denoting the integration time of the LPF. The statistical average of S A
is Mσ E 2 , where σ E 2 is the variance of each degree of freedom in E ( t ) . Assuming that the
additive noise has a rectangular power spectrum with bandwidth B, the average power of the
detected noise is N 0 BT = N 0 M / 2 such that the OSNR is OSNR = 2σ E / N 0 , or
2
N 0 = 2σ E / OSNR . Thus we find that
2
4σ E 2 S A ,
VAR( N | E ) = (A.11)
OSNR
which can be substituted into equation (A.9) for the BER. The effective rate factor is equal to
1 minus the probability that either Alice or Bob detect a signal that is between the two
thresholds. This is given by a simple, but cumbersome expression:
P (d ) = f ( S A ) dS A
sh
∫sl
sl − S A sh − S A
f ( S A ) dS A +
sl
⎡ ⎤⎞
⎛ ⎞ ⎛
+ −Q
Q
⎢∫ ⎥⎟
⎜ ⎟ ⎜
(A.12)
VAR ( N | E ) VAR( N | E )
0
⎢ ⎥⎠
⎝ ⎠ ⎝
⎣ ⎦
S A − sh S A − sl
∞
f ( S A ) dS A
⎡ ⎤⎞
⎛ ⎞ ⎛
+ −Q
Q
⎢∫ ⎥⎟
⎜ ⎟ ⎜
VAR( N | E ) VAR( N | E )
sh
⎢ ⎥⎠
⎝ ⎠ ⎝
⎣ ⎦
the first line of which represents the probability of a quot;don't carequot; on Alices side, whereas the
last two lines represent the probability of a don't care on Bob's side provided that Alice
detected a legitimate symbol (quot;zeroquot; or quot;onequot;). When both polarizations are included, the
effect is equivalent to that of doubling the number of degrees of freedom from M=2BT to
M=4BT.
Acknowledgement
The authors are grateful to Efraim Roif and to Civcom for providing the tunable dispersion
compensation devices. The authors are also pleased to acknowledge the advice of Gerard
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3395
14. Cohen and Simon Litsyn and their help in understanding the operation of privacy
amplification protocols.
#89478 - $15.00 USD Received 6 Nov 2007; revised 12 Jan 2008; accepted 15 Jan 2008; published 28 Feb 2008
(C) 2008 OSA 3 March 2008 / Vol. 16, No. 5 / OPTICS EXPRESS 3396