This document provides information about the CS8792 CRYPTOGRAPHY & NETWORK SECURITY course. It discusses cryptography, the course outcomes, syllabus, and key concepts in cryptography including symmetric encryption, asymmetric encryption, data integrity algorithms, and authentication protocols. It also covers essential network and computer security requirements, legal and ethical issues, security policies, OSI security architecture including security attacks, mechanisms, and services.
This document discusses encryption techniques. It mentions the Hill Cipher, which is a method of encrypting messages where each letter is represented by a number and the encryption uses matrix multiplication. The document also references matrix sizes of 2x2 and 3x3, indicating it may be comparing different versions of the Hill Cipher that use different sized matrices for the encryption.
This document provides an overview of IP security (IPSec). It begins by explaining the need for IPSec due to the lack of security in standard Internet protocols. It then covers the basic architecture and components of IPSec, including authentication headers, encapsulating security payloads, and how security associations combine these elements. The document also discusses key management and provides examples of how IPSec can be implemented in transport and tunnel modes. In under 3 sentences, this document provides an introduction to IPSec, outlines its main architectural components, and discusses how it establishes security associations to encrypt and authenticate network traffic.
Principles of public key cryptography and its UsesMohsin Ali
This document discusses the principles of public key cryptography. It begins by defining asymmetric encryption and how it uses a public key and private key instead of a single shared key. It then discusses key concepts like digital certificates and public key infrastructure. The document also provides examples of how public key cryptography can be used, including the RSA algorithm and key distribution methods like public key directories and certificates. It explains how public key cryptography solves the key distribution problem present in symmetric encryption.
Digital signatures provide authentication of digital messages or documents. There are three main algorithms involved: hashing, signature generation, and signature verification. Common digital signature schemes include ElGamal, Schnorr, and the Digital Signature Standard (DSS). The DSS is based on ElGamal and Schnorr schemes. It uses smaller signatures than ElGamal by employing two moduli, one smaller than the other. Digital signatures are widely used to provide authentication in protocols like IPSec, SSL/TLS, and S/MIME.
1) The document discusses various transposition ciphers including the rail fence cipher, route cipher, simple columnar transposition, and double transposition cipher. It explains how each cipher works through encrypting and decrypting sample messages.
2) Detection methods for transposition ciphers are also covered, such as frequency analysis and finding anagrams in the ciphertext. Simpler transposition ciphers can be vulnerable to these kinds of cryptanalysis techniques.
3) Genetic algorithms are mentioned as a way for cryptanalysts to find the most likely decryption key through probability calculations.
This document discusses message authentication codes (MACs). It explains that MACs use a shared symmetric key to authenticate messages, ensuring integrity and validating the sender. The document outlines the MAC generation and verification process, and notes that MACs provide authentication but not encryption. It then describes HMAC specifically, which applies a cryptographic hash function to the message and key to generate the MAC. The key steps of the HMAC process are detailed.
This document provides information about the CS8792 CRYPTOGRAPHY & NETWORK SECURITY course. It discusses cryptography, the course outcomes, syllabus, and key concepts in cryptography including symmetric encryption, asymmetric encryption, data integrity algorithms, and authentication protocols. It also covers essential network and computer security requirements, legal and ethical issues, security policies, OSI security architecture including security attacks, mechanisms, and services.
This document discusses encryption techniques. It mentions the Hill Cipher, which is a method of encrypting messages where each letter is represented by a number and the encryption uses matrix multiplication. The document also references matrix sizes of 2x2 and 3x3, indicating it may be comparing different versions of the Hill Cipher that use different sized matrices for the encryption.
This document provides an overview of IP security (IPSec). It begins by explaining the need for IPSec due to the lack of security in standard Internet protocols. It then covers the basic architecture and components of IPSec, including authentication headers, encapsulating security payloads, and how security associations combine these elements. The document also discusses key management and provides examples of how IPSec can be implemented in transport and tunnel modes. In under 3 sentences, this document provides an introduction to IPSec, outlines its main architectural components, and discusses how it establishes security associations to encrypt and authenticate network traffic.
Principles of public key cryptography and its UsesMohsin Ali
This document discusses the principles of public key cryptography. It begins by defining asymmetric encryption and how it uses a public key and private key instead of a single shared key. It then discusses key concepts like digital certificates and public key infrastructure. The document also provides examples of how public key cryptography can be used, including the RSA algorithm and key distribution methods like public key directories and certificates. It explains how public key cryptography solves the key distribution problem present in symmetric encryption.
Digital signatures provide authentication of digital messages or documents. There are three main algorithms involved: hashing, signature generation, and signature verification. Common digital signature schemes include ElGamal, Schnorr, and the Digital Signature Standard (DSS). The DSS is based on ElGamal and Schnorr schemes. It uses smaller signatures than ElGamal by employing two moduli, one smaller than the other. Digital signatures are widely used to provide authentication in protocols like IPSec, SSL/TLS, and S/MIME.
1) The document discusses various transposition ciphers including the rail fence cipher, route cipher, simple columnar transposition, and double transposition cipher. It explains how each cipher works through encrypting and decrypting sample messages.
2) Detection methods for transposition ciphers are also covered, such as frequency analysis and finding anagrams in the ciphertext. Simpler transposition ciphers can be vulnerable to these kinds of cryptanalysis techniques.
3) Genetic algorithms are mentioned as a way for cryptanalysts to find the most likely decryption key through probability calculations.
This document discusses message authentication codes (MACs). It explains that MACs use a shared symmetric key to authenticate messages, ensuring integrity and validating the sender. The document outlines the MAC generation and verification process, and notes that MACs provide authentication but not encryption. It then describes HMAC specifically, which applies a cryptographic hash function to the message and key to generate the MAC. The key steps of the HMAC process are detailed.
The document describes the one-time pad cipher, which is considered theoretically unbreakable. It works by combining a plaintext message with a randomly generated key that is at least as long as the message. Each character of the key is combined with the corresponding character of the message using modular arithmetic. The key is then destroyed after use, and both the sender and receiver must have identical copies of the key to encrypt and decrypt messages. It provides perfect secrecy because an attacker with infinite computing power could not determine the original plaintext without the key.
This document discusses data encryption methods. It defines encryption as hiding information so it can only be accessed by those with the key. There are two main types: symmetric encryption uses one key, while asymmetric encryption uses two different but related keys. Encryption works by scrambling data using techniques like transposition, which rearranges the order, and substitution, which replaces parts with other values. The document specifically describes the Data Encryption Standard (DES) algorithm and the public key cryptosystem, which introduced the innovative approach of using different keys for encryption and decryption.
The document contains descriptions and figures about stop-and-wait, sliding window, and selective reject transmission protocols. Stop-and-wait uses acknowledgments to ensure frames are received correctly one at a time, while sliding window protocols allow multiple unacknowledged frames to be sent by keeping a window of outstanding frames. The figures demonstrate examples of how these protocols handle damaged frames, lost frames, and lost acknowledgments to ensure reliable data transmission.
The document discusses intrusion detection and various types of intruders and intrusion techniques. It covers password capture methods like watching someone enter their password or using a Trojan horse. It also discusses different types of intrusion detection approaches like statistical anomaly detection, rule-based detection, and honeypots. The document then covers password management, viruses, worms, and distributed denial of service attacks. It concludes by discussing firewall design principles and characteristics like packet filtering routers.
MD5 is a cryptographic hash function that produces a 128-bit hash value for a message of any length. It was originally designed to provide authentication of digital signatures but is no longer considered reliable for cryptography due to techniques that can generate collisions. MD5 operates by padding the input, appending the length, dividing into blocks, initializing variables, processing blocks through 4 rounds of operations with different constants each round, and outputting the hash value. While it was intended to be difficult to find collisions or recover the input, MD5 is no longer considered cryptographically secure due to attacks demonstrating collisions.
- DES (Data Encryption Standard) is a symmetric block cipher algorithm that encrypts data in 64-bit blocks using a 56-bit key. It was the first encryption standard adopted by the U.S. government for protecting sensitive unclassified federal government information.
- DES works by performing 16 rounds of complex substitutions and permutations on each data block, encrypting it using the key. It has various modes of operation like ECB, CBC, CFB, OFB, and CTR that specify how it operates on data.
- In 1998, DES was broken using a brute force attack by the Electronic Frontier Foundation in just 3 days, showing the need for stronger algorithms like AES which replaced DES as the encryption standard
Transport Layer Services : Multiplexing And DemultiplexingKeyur Vadodariya
This document discusses the transport layer of computer networks. It begins with introducing the group members and topic, which is the transport layer introduction, services, multiplexing and demultiplexing. Then it provides definitions of the transport layer, its functions and services. It describes how the transport layer provides process to process delivery, end-to-end connections, congestion control, data integrity, flow control, multiplexing and demultiplexing. It explains the differences between connectionless and connection-oriented multiplexing and demultiplexing. In the end, it lists some references.
Public key cryptography uses two keys, a public key that can encrypt messages and a private key that decrypts messages. It has six components: plain text, encryption algorithm, public and private keys, ciphertext, and decryption algorithm. Some key characteristics are that it is computationally infeasible to determine the private key from the public key alone, and encryption/decryption is easy when the relevant key is known. The requirements of public key cryptography are that it is easy to generate a public-private key pair, easy to encrypt with the public key, easy for the recipient to decrypt with the private key, and infeasible to determine the private key from the public key or recover the plaintext from the ciphertext and public key alone
Key management is the set of techniques and procedures for establishing and maintaining secure key relationships between parties. It involves generating, distributing, storing, updating, and revoking cryptographic keys. The objectives of key management are to maintain secure keying material and relationships to counter relevant threats like key compromise, in accordance with a security policy. Techniques include symmetric and public-key encryption, key hierarchies, certificates, and life cycle processes around user registration and key installation, update, and destruction.
In cryptography, a block cipher is a deterministic algorithm operating on ... Systems as a means to effectively improve security by combining simple operations such as .... Finally, the cipher should be easily cryptanalyzable, such that it can be ...
5. message authentication and hash functionChirag Patel
1) Message authentication can be achieved through message encryption, message authentication codes (MACs), or hash functions.
2) MACs provide authentication by appending a fixed-size block that depends on the message and a secret key. Receivers can verify messages by recomputing the MAC.
3) Hash functions map variable-length data to fixed-length outputs and are easy to compute but infeasible to reverse or find collisions. Common hash functions include MD5 and SHA-512.
This document discusses block ciphers, including their definition, structure, design principles, and avalanche effect. A block cipher operates on fixed-length blocks of bits and uses a symmetric key. It encrypts bits in blocks rather than one by one. Block ciphers have advantages like high diffusion but are slower than stream ciphers. They are built using the Feistel cipher structure with a number of rounds and keys. Important design principles for block ciphers include the number of rounds, design of the round function, and key schedule algorithm. The avalanche effect causes a small input change to result in a significant output change.
CS8792 - Cryptography and Network Securityvishnukp34
this is an engineering subject.this consist of
pgno: 5 - Information security in past & present
pgno: 7 - Aim of Course
pgno: 8 - OSI Security Architecture
pgno: 9 - Security Goals – CIA Triad
pgno: 13 - Aspects of Security
pgno: 17 - ATTACKS
pgno: 22 - Passive Versus Active Attacks
pgno: 23 - SERVICES AND MECHANISMS
Security Hash Algorithm (SHA) was developed in 1993 by the National Institute of Standards and Technology (NIST) and National Security Agency (NSA).
It was designed as the algorithm to be used for secure hashing in the US Digital Signature Standard.
• Hashing function is one of the most commonly used encryption methods. A hash is a special mathematical function that performs one-way encryption.
• SHA-l is a revised version of SHA designed by NIST and was published as a Federal Information Processing Standard (FIPS).
• Like MD5, SHA-l processes input data in 512-bit blocks.
• SHA-l generates a 160-bit message digest. Whereas MD5 generated message digest of 128 bits.
• The procedure is used to send a non secret but signed message from sender to receiver. In such a case following steps are followed:
1. Sender feeds a plaintext message into SHA-l algorithm and obtains a 160-bit SHA-l hash.
2. Sender then signs the hash with his RSA private key and sends both the plaintext message and the signed hash to the receiver.
3. After receiving the message, the receiver computes the SHA-l hash himself and also applies the sender's public key to the signed hash to obtain the original hash H.
This document discusses product ciphers, which combine substitution and transposition ciphers for stronger encryption. It provides an example of encrypting the plaintext "COMPUTER" using a two-step product cipher. First, substitution encryption is done using a 6x6 matrix. Then, transposition encryption is performed by rearranging the ciphertext columns according to a keyword. The document explains how to encrypt another plaintext "CRYPTOGRAPHY" using the same technique with a different keyword.
The presentation describes basics of cryptography and information security. It covers goals of cryptography, history of cipher symmetric and public key cryptography
- Traditional symmetric key ciphers can be categorized as either substitution ciphers, which replace symbols, or transposition ciphers, which change the location of symbols.
- For substitution ciphers, the document describes various monoalphabetic ciphers (such as the Caesar cipher) and polyalphabetic ciphers (such as the Vigenere cipher and Hill cipher).
- For transposition ciphers, it discusses both keyless transposition techniques like the rail fence cipher as well as keyed transposition ciphers that permute symbols within blocks defined by a key.
The document summarizes key concepts related to symmetric ciphers. It discusses traditional ciphers such as substitution ciphers (monoalphabetic and polyalphabetic) and transposition ciphers. It also introduces modern categories of stream ciphers and block ciphers. Specific traditional ciphers covered include the Caesar cipher, Vigenere cipher, Playfair cipher, Hill cipher, and the one-time pad. The document emphasizes that the security of symmetric ciphers relies on keeping the secret key private.
The document describes the one-time pad cipher, which is considered theoretically unbreakable. It works by combining a plaintext message with a randomly generated key that is at least as long as the message. Each character of the key is combined with the corresponding character of the message using modular arithmetic. The key is then destroyed after use, and both the sender and receiver must have identical copies of the key to encrypt and decrypt messages. It provides perfect secrecy because an attacker with infinite computing power could not determine the original plaintext without the key.
This document discusses data encryption methods. It defines encryption as hiding information so it can only be accessed by those with the key. There are two main types: symmetric encryption uses one key, while asymmetric encryption uses two different but related keys. Encryption works by scrambling data using techniques like transposition, which rearranges the order, and substitution, which replaces parts with other values. The document specifically describes the Data Encryption Standard (DES) algorithm and the public key cryptosystem, which introduced the innovative approach of using different keys for encryption and decryption.
The document contains descriptions and figures about stop-and-wait, sliding window, and selective reject transmission protocols. Stop-and-wait uses acknowledgments to ensure frames are received correctly one at a time, while sliding window protocols allow multiple unacknowledged frames to be sent by keeping a window of outstanding frames. The figures demonstrate examples of how these protocols handle damaged frames, lost frames, and lost acknowledgments to ensure reliable data transmission.
The document discusses intrusion detection and various types of intruders and intrusion techniques. It covers password capture methods like watching someone enter their password or using a Trojan horse. It also discusses different types of intrusion detection approaches like statistical anomaly detection, rule-based detection, and honeypots. The document then covers password management, viruses, worms, and distributed denial of service attacks. It concludes by discussing firewall design principles and characteristics like packet filtering routers.
MD5 is a cryptographic hash function that produces a 128-bit hash value for a message of any length. It was originally designed to provide authentication of digital signatures but is no longer considered reliable for cryptography due to techniques that can generate collisions. MD5 operates by padding the input, appending the length, dividing into blocks, initializing variables, processing blocks through 4 rounds of operations with different constants each round, and outputting the hash value. While it was intended to be difficult to find collisions or recover the input, MD5 is no longer considered cryptographically secure due to attacks demonstrating collisions.
- DES (Data Encryption Standard) is a symmetric block cipher algorithm that encrypts data in 64-bit blocks using a 56-bit key. It was the first encryption standard adopted by the U.S. government for protecting sensitive unclassified federal government information.
- DES works by performing 16 rounds of complex substitutions and permutations on each data block, encrypting it using the key. It has various modes of operation like ECB, CBC, CFB, OFB, and CTR that specify how it operates on data.
- In 1998, DES was broken using a brute force attack by the Electronic Frontier Foundation in just 3 days, showing the need for stronger algorithms like AES which replaced DES as the encryption standard
Transport Layer Services : Multiplexing And DemultiplexingKeyur Vadodariya
This document discusses the transport layer of computer networks. It begins with introducing the group members and topic, which is the transport layer introduction, services, multiplexing and demultiplexing. Then it provides definitions of the transport layer, its functions and services. It describes how the transport layer provides process to process delivery, end-to-end connections, congestion control, data integrity, flow control, multiplexing and demultiplexing. It explains the differences between connectionless and connection-oriented multiplexing and demultiplexing. In the end, it lists some references.
Public key cryptography uses two keys, a public key that can encrypt messages and a private key that decrypts messages. It has six components: plain text, encryption algorithm, public and private keys, ciphertext, and decryption algorithm. Some key characteristics are that it is computationally infeasible to determine the private key from the public key alone, and encryption/decryption is easy when the relevant key is known. The requirements of public key cryptography are that it is easy to generate a public-private key pair, easy to encrypt with the public key, easy for the recipient to decrypt with the private key, and infeasible to determine the private key from the public key or recover the plaintext from the ciphertext and public key alone
Key management is the set of techniques and procedures for establishing and maintaining secure key relationships between parties. It involves generating, distributing, storing, updating, and revoking cryptographic keys. The objectives of key management are to maintain secure keying material and relationships to counter relevant threats like key compromise, in accordance with a security policy. Techniques include symmetric and public-key encryption, key hierarchies, certificates, and life cycle processes around user registration and key installation, update, and destruction.
In cryptography, a block cipher is a deterministic algorithm operating on ... Systems as a means to effectively improve security by combining simple operations such as .... Finally, the cipher should be easily cryptanalyzable, such that it can be ...
5. message authentication and hash functionChirag Patel
1) Message authentication can be achieved through message encryption, message authentication codes (MACs), or hash functions.
2) MACs provide authentication by appending a fixed-size block that depends on the message and a secret key. Receivers can verify messages by recomputing the MAC.
3) Hash functions map variable-length data to fixed-length outputs and are easy to compute but infeasible to reverse or find collisions. Common hash functions include MD5 and SHA-512.
This document discusses block ciphers, including their definition, structure, design principles, and avalanche effect. A block cipher operates on fixed-length blocks of bits and uses a symmetric key. It encrypts bits in blocks rather than one by one. Block ciphers have advantages like high diffusion but are slower than stream ciphers. They are built using the Feistel cipher structure with a number of rounds and keys. Important design principles for block ciphers include the number of rounds, design of the round function, and key schedule algorithm. The avalanche effect causes a small input change to result in a significant output change.
CS8792 - Cryptography and Network Securityvishnukp34
this is an engineering subject.this consist of
pgno: 5 - Information security in past & present
pgno: 7 - Aim of Course
pgno: 8 - OSI Security Architecture
pgno: 9 - Security Goals – CIA Triad
pgno: 13 - Aspects of Security
pgno: 17 - ATTACKS
pgno: 22 - Passive Versus Active Attacks
pgno: 23 - SERVICES AND MECHANISMS
Security Hash Algorithm (SHA) was developed in 1993 by the National Institute of Standards and Technology (NIST) and National Security Agency (NSA).
It was designed as the algorithm to be used for secure hashing in the US Digital Signature Standard.
• Hashing function is one of the most commonly used encryption methods. A hash is a special mathematical function that performs one-way encryption.
• SHA-l is a revised version of SHA designed by NIST and was published as a Federal Information Processing Standard (FIPS).
• Like MD5, SHA-l processes input data in 512-bit blocks.
• SHA-l generates a 160-bit message digest. Whereas MD5 generated message digest of 128 bits.
• The procedure is used to send a non secret but signed message from sender to receiver. In such a case following steps are followed:
1. Sender feeds a plaintext message into SHA-l algorithm and obtains a 160-bit SHA-l hash.
2. Sender then signs the hash with his RSA private key and sends both the plaintext message and the signed hash to the receiver.
3. After receiving the message, the receiver computes the SHA-l hash himself and also applies the sender's public key to the signed hash to obtain the original hash H.
This document discusses product ciphers, which combine substitution and transposition ciphers for stronger encryption. It provides an example of encrypting the plaintext "COMPUTER" using a two-step product cipher. First, substitution encryption is done using a 6x6 matrix. Then, transposition encryption is performed by rearranging the ciphertext columns according to a keyword. The document explains how to encrypt another plaintext "CRYPTOGRAPHY" using the same technique with a different keyword.
The presentation describes basics of cryptography and information security. It covers goals of cryptography, history of cipher symmetric and public key cryptography
- Traditional symmetric key ciphers can be categorized as either substitution ciphers, which replace symbols, or transposition ciphers, which change the location of symbols.
- For substitution ciphers, the document describes various monoalphabetic ciphers (such as the Caesar cipher) and polyalphabetic ciphers (such as the Vigenere cipher and Hill cipher).
- For transposition ciphers, it discusses both keyless transposition techniques like the rail fence cipher as well as keyed transposition ciphers that permute symbols within blocks defined by a key.
The document summarizes key concepts related to symmetric ciphers. It discusses traditional ciphers such as substitution ciphers (monoalphabetic and polyalphabetic) and transposition ciphers. It also introduces modern categories of stream ciphers and block ciphers. Specific traditional ciphers covered include the Caesar cipher, Vigenere cipher, Playfair cipher, Hill cipher, and the one-time pad. The document emphasizes that the security of symmetric ciphers relies on keeping the secret key private.
This document provides an overview of traditional symmetric-key ciphers. It begins by defining symmetric-key ciphers and their basic components. It then outlines the chapter's objectives and topics, which include substitution and transposition ciphers as well as cryptanalysis techniques. The document proceeds to describe various substitution ciphers like monoalphabetic, polyalphabetic, additive, affine and Playfair ciphers. It also covers transposition ciphers, including keyless rail fence cipher and keyed block permutation ciphers. Examples are provided to illustrate encryption and decryption processes for different ciphers.
This document provides an overview of traditional symmetric-key ciphers. It begins by defining symmetric-key ciphers and their basic components. It then outlines the chapter's objectives and topics: substitution ciphers, transposition ciphers, stream ciphers, and block ciphers. The document proceeds to describe various traditional ciphers that fall under each of these categories, including monoalphabetic and polyalphabetic substitution ciphers, rail fence transposition cipher, and the Enigma machine cipher. It provides examples of encrypting and decrypting messages with these different ciphers.
This document discusses various topics in network security including cryptography, symmetric and asymmetric encryption algorithms, digital signatures, and firewalls. It provides detailed explanations and examples of symmetric key algorithms like monoalphabetic and polyalphabetic substitution ciphers, transpositional ciphers, and block ciphers like DES. It also covers asymmetric key algorithms like RSA and their use for encryption and digital signatures. Finally, it describes packet filter and proxy based firewalls and how they can be used to control network access.
This document discusses traditional symmetric key ciphers. It describes how symmetric key ciphers use the same key to encrypt and decrypt data. The document categorizes traditional symmetric key ciphers into substitution ciphers like monoalphabetic and polyalphabetic ciphers, and transposition ciphers like keyed and keyless transposition ciphers. It also provides examples of how different symmetric key ciphers like the Caesar cipher, shift cipher, additive cipher, and multiplicative cipher operate.
This document discusses different techniques used in cryptography. It describes symmetric and asymmetric key cryptography. Symmetric cryptography uses a single secret key for encryption and decryption, while asymmetric cryptography uses public and private key pairs. The document also explains the Caesar cipher, Playfair cipher, polyalphabetic cipher, and transposition ciphers like the rail fence technique. It provides examples to illustrate how each technique works and encrypts messages.
Network security relies heavily on cryptography, which transforms messages to make them secure. There are two main categories of cryptography: symmetric-key cryptography where the same key is used to encrypt and decrypt, and asymmetric-key cryptography where different keys are used for encryption and decryption. Traditional symmetric-key ciphers include substitution ciphers that replace symbols and transposition ciphers that rearrange symbols. Modern symmetric-key ciphers operate on bits and are more complex.
The document summarizes classical encryption techniques, including:
- Symmetric encryption uses a shared key between sender and receiver for encryption/decryption.
- Early techniques included the Caesar cipher (shifting letters), monoalphabetic cipher (mapping each letter to another), and Playfair cipher (encrypting letter pairs).
- The Vigenère cipher improved security by using a keyword to select different Caesar ciphers for successive letters, making it a polyalphabetic cipher.
Cryptography is the study of techniques for securing communication and information. The document provides an introduction to cryptography, including definitions of encryption, decryption, plaintext and ciphertext. It discusses classical ciphers like the Caesar cipher, monoalphabetic and polyalphabetic ciphers, the Playfair cipher, Vigenère cipher and the one-time pad cipher. It also covers cryptanalysis techniques and introduces concepts in modern cryptography like symmetric and asymmetric key cryptography.
The document provides an overview of cryptography concepts including encryption, decryption, symmetric cryptosystems, block ciphers, substitution ciphers, the one-time pad, and algorithms such as DES, Triple DES, AES, and others. Key points covered include Kerckhoffs's principle of keeping algorithms public and keys private, how symmetric encryption works between two parties with a shared key, methods of encrypting plaintext in blocks or as a bit stream, techniques like substitution and transposition ciphers, weaknesses of approaches like the Hill cipher, and the history and operation of standard block ciphers.
The document discusses cryptography and the RSA encryption algorithm. It begins with an introduction to cryptography and its uses. It then covers the history of cryptography, common security issues, and different cryptographic techniques like symmetric and asymmetric encryption. The document focuses on explaining the RSA algorithm, how it works using public and private keys, and why factoring large numbers makes RSA secure. It provides an overview of the key aspects of cryptography and the RSA algorithm.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Enhancing security of caesar cipher using differenteSAT Journals
Abstract Cryptography is an art and science of converting original message into non readable form. There are two techniques for converting data into no readable form:1)Transposition technique 2)Substitution technique. Caesar cipher is an example of substitution method. As Caesar cipher has various limitations so this talk will present a perspective on combination of techniques substitution and transposition. In this paper I have focused on the well known classical techniques the aim was to induce some strength to these classical encryption for that purpose I blended classical encryption with the some more techniques. my proposed method showed that it is better in terms of providing more security to any given text message. In our experiments I took Caesaer Ciphers as representatives of Classical Techniques. To make it more secure I have used some techniques like I have used multiple level Row Transposition Ciphers, encryption with same key at each level and encryption with different key at each level. Keywords— substitution, transposition, cryptography, Caesar cipher
This document discusses classical encryption techniques such as symmetric encryption, where a shared key is used for encryption and decryption. It defines terminology like plaintext, ciphertext, encryption, and decryption. Symmetric ciphers require a strong algorithm and secret key. Classical ciphers discussed include the Caesar cipher, monoalphabetic ciphers, Playfair cipher, Vigenère cipher, and the one-time pad. It also covers transposition ciphers like the rail fence cipher and steganography.
This document summarizes classical encryption techniques discussed in Chapter 2. It describes symmetric encryption methods that use a shared secret key, such as the Caesar cipher and monoalphabetic ciphers. It also covers the Playfair cipher, polyalphabetic ciphers like the Vigenère cipher, and transposition ciphers. More complex techniques are discussed like product ciphers implemented using rotor machines. The document also defines cryptography terminology and approaches to cryptanalysis like frequency analysis.
Jaimin chp-8 - network security-new -use this - 2011 batchJaimin Jani
The document discusses cryptography concepts including symmetric and asymmetric encryption algorithms like DES, AES, RSA. It explains the basic working principles of RSA including key generation using large prime numbers, modular arithmetic and the concept of one-way functions that make private key derivation difficult. It also covers cryptographic modes of operation like ECB, CBC that are used to encrypt data blocks of arbitrary length.
The document discusses various techniques for encrypting messages to provide security in communication. It describes:
1. Traditional encryption techniques like the Caesar cipher, monoalphabetic ciphers, the Playfair cipher, and polyalphabetic ciphers like the Vigenere cipher. These techniques encrypt messages by substituting or transposing letters.
2. The importance of keeping encryption algorithms and keys secret to prevent cryptanalysis attacks. Brute force attacks try every possible key to decrypt messages.
3. How more advanced techniques like using multiple cipher alphabets and large keys spaces make cryptanalysis much more difficult compared to simple ciphers like the Caesar cipher.
The document discusses cryptography concepts including encryption, decryption, symmetric and asymmetric encryption techniques, cryptanalysis methods like brute force attacks, and the importance of secret keys. Symmetric encryption uses a shared secret key by both sender and receiver, while asymmetric encryption uses different public/private keys. Cryptanalysis aims to discover plaintext or keys by techniques like brute force trials or exploiting algorithm weaknesses. Longer cryptographic keys increase the difficulty of brute force attacks breaking the encryption.
This document discusses cryptography techniques including substitution ciphers, transposition ciphers, and advanced symmetric key methods. It provides examples of encrypting and decrypting messages using a Caesar cipher with shifting substitutions, a transposition cipher that writes messages in rows and reads them out in columns according to a keyword, and a simplified polyalphabetic cipher that shifts the substitution after each character. Frequency analysis and brute force attacks are also discussed as techniques for breaking simple ciphers.
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A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEMHODECEDSIET
Time Division Multiplexing (TDM) is a method of transmitting multiple signals over a single communication channel by dividing the signal into many segments, each having a very short duration of time. These time slots are then allocated to different data streams, allowing multiple signals to share the same transmission medium efficiently. TDM is widely used in telecommunications and data communication systems.
### How TDM Works
1. **Time Slots Allocation**: The core principle of TDM is to assign distinct time slots to each signal. During each time slot, the respective signal is transmitted, and then the process repeats cyclically. For example, if there are four signals to be transmitted, the TDM cycle will divide time into four slots, each assigned to one signal.
2. **Synchronization**: Synchronization is crucial in TDM systems to ensure that the signals are correctly aligned with their respective time slots. Both the transmitter and receiver must be synchronized to avoid any overlap or loss of data. This synchronization is typically maintained by a clock signal that ensures time slots are accurately aligned.
3. **Frame Structure**: TDM data is organized into frames, where each frame consists of a set of time slots. Each frame is repeated at regular intervals, ensuring continuous transmission of data streams. The frame structure helps in managing the data streams and maintaining the synchronization between the transmitter and receiver.
4. **Multiplexer and Demultiplexer**: At the transmitting end, a multiplexer combines multiple input signals into a single composite signal by assigning each signal to a specific time slot. At the receiving end, a demultiplexer separates the composite signal back into individual signals based on their respective time slots.
### Types of TDM
1. **Synchronous TDM**: In synchronous TDM, time slots are pre-assigned to each signal, regardless of whether the signal has data to transmit or not. This can lead to inefficiencies if some time slots remain empty due to the absence of data.
2. **Asynchronous TDM (or Statistical TDM)**: Asynchronous TDM addresses the inefficiencies of synchronous TDM by allocating time slots dynamically based on the presence of data. Time slots are assigned only when there is data to transmit, which optimizes the use of the communication channel.
### Applications of TDM
- **Telecommunications**: TDM is extensively used in telecommunication systems, such as in T1 and E1 lines, where multiple telephone calls are transmitted over a single line by assigning each call to a specific time slot.
- **Digital Audio and Video Broadcasting**: TDM is used in broadcasting systems to transmit multiple audio or video streams over a single channel, ensuring efficient use of bandwidth.
- **Computer Networks**: TDM is used in network protocols and systems to manage the transmission of data from multiple sources over a single network medium.
### Advantages of TDM
- **Efficient Use of Bandwidth**: TDM all
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
imaging, emphasizing addressing false positives and resource efficiency.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
2. Unit – I INTRODUCTION
• Security trends - Legal, Ethical and
Professional Aspects of Security, Need for
Security at Multiple levels, Security Policies -
Model of network security – Security attacks,
services and mechanisms – OSI security
architecture – Classical encryption techniques:
substitution techniques, transposition
techniques, steganography- Foundations of
modern cryptography: perfect security –
information theory – product cryptosystem –
4. Some Basic Terminology
• Plaintext - original message
• Ciphertext - coded message
• Cipher - algorithm for transforming plaintext to ciphertext
• Key - information used in cipher known only to
sender/receiver
• Encipher (encrypt) - converting plaintext to ciphertext
• Decipher (decrypt) - recovering ciphertext from plaintext
• Cryptography - study of encryption principles/methods
• Cryptanalysis (codebreaking) - study of principles/ methods
of deciphering ciphertext without knowing key
6. Cryptography
• Characterize cryptographic system by:
– Type of encryption operations used
• Substitution / Transposition / Product
– Number of keys used
• Single-key or Private / Two-key or Public
– Way in which plaintext is processed
• Block / Stream
7. Cryptanalysis
• Objective to recover key not just message
• General approaches:
– Cryptanalytic attack
• Knowledge of algorithm and some part of plaintext
– Brute-force attack
• Try every possible key on cipher text to get a meaningful
plain text
8. 3-1 INTRODUCTION
Figure 3.1 shows the general idea behind a symmetric-key
cipher. The original message from Alice to Bob is called
plaintext; the message that is sent through the channel is
called the ciphertext. To create the ciphertext from the
plaintext, Alice uses an encryption algorithm and a shared
secret key. To create the plaintext from ciphertext, Bob
uses a decryption algorithm and the same secret key.
3.1.1 Kerckhoff’s Principle
3.1.2 Cryptanalysis
3.1.3 Categories of Traditional Ciphers
Topics discussed in this section:
12. 3.1.1 Kerckhoff’s Principle
Based on Kerckhoff’s principle, one should always
assume that the adversary, Eve, knows the
encryption/decryption algorithm. The resistance of the
cipher to attack must be based only on the secrecy of the
key.
13. 3.1.2 Cryptanalysis
As cryptography is the science and art of creating secret
codes, cryptanalysis is the science and art of breaking
those codes.
Figure 3.3 Cryptanalysis attacks
19. Substitution Techniques
• Caesar cipher
• Monoalphabetic cipher
• Play fair cipher
• Hill cipher
• Polyalphabetic cipher
• One time pad
20. Classical Substitution Ciphers
• Letters of plaintext are replaced by other
letters or by numbers or symbols
• If plaintext is viewed as a sequence of bits,
then substitution involves replacing plaintext
bit patterns with cipher text bit patterns
21. 3-2 SUBSTITUTION CIPHERS
A substitution cipher replaces one symbol with another.
Substitution ciphers can be categorized as either
monoalphabetic ciphers or polyalphabetic ciphers.
3.2.1 Monoalphabetic Ciphres
3.2.2 Polyalphabetic Ciphers
Topics discussed in this section:
A substitution cipher replaces one
symbol with another.
Note
22. 3.2.1 Monoalphabetic Ciphers
In monoalphabetic substitution, the
relationship between a symbol in the
plaintext to a symbol in the ciphertext is
always one-to-one.
Note
23. 3.2.1 Continued
The following shows a plaintext and its corresponding ciphertext.
The cipher is probably monoalphabetic because both l’s (els) are
encrypted as O’s.
Example 3.1
24. 3.2.1 Continued
The simplest monoalphabetic cipher is the additive cipher. This
cipher is sometimes called a shift cipher and sometimes a Caesar
cipher, but the term additive cipher better reveals its
mathematical nature.
Additive Cipher
Figure 3.8 Plaintext and ciphertext in Z26
25. Figure 3.9 Additive cipher
3.2.1 Continued
When the cipher is additive, the
plaintext, ciphertext, and key are
integers in Z26.
Note
26. 3.2.1 Continued
Use the additive cipher with key = 15 to encrypt the message
“hello”.
Example 3.3
We apply the encryption algorithm to the plaintext, character by
character:
Solution
27. 3.2.1 Continued
Use the additive cipher with key = 15 to decrypt the message
“WTAAD”.
Example 3.4
We apply the decryption algorithm to the plaintext character by
character:
Solution
28. 3.2.1 Continued
Historically, additive ciphers are called shift ciphers. Julius Caesar
used an additive cipher to communicate with his officers. For this
reason, additive ciphers are sometimes referred to as the Caesar
cipher. Caesar used a key of 3 for his communications.
Shift Cipher and Caesar Cipher
Additive ciphers are sometimes referred
to as shift ciphers or Caesar cipher.
Note
29. 3.2.1 Continued
Eve has intercepted the ciphertext “UVACLYFZLJBYL”. Show
how she can use a brute-force attack to break the cipher.
Example 3.5
Eve tries keys from 1 to 7. With a key of 7, the plaintext is “not
very secure”, which makes sense.
Solution
30. 3.2.1 Continued
Table 3.1 Frequency of characters in English
Table 3.2 Frequency of diagrams and trigrams
31. 3.2.1 Continued
Multiplicative Ciphers
In a multiplicative cipher, the plaintext
and ciphertext are integers in Z26; the
key is an integer in Z26*.
Note
Figure 3.10 Multiplicative cipher
32. 3.2.1 Continued
What is the key domain for any multiplicative cipher?
Example 3.7
The key needs to be in Z26*. This set has only 12 members: 1, 3, 5,
7, 9, 11, 15, 17, 19, 21, 23, 25.
Solution
We use a multiplicative cipher to encrypt the message “hello” with
a key of 7. The ciphertext is “XCZZU”.
Example 3.8
34. 3.2.1 Continued
The affine cipher uses a pair of keys in which the first key is from
Z26* and the second is from Z26. The size of the key domain is
26 × 12 = 312.
Example 3.09
Use an affine cipher to encrypt the message “hello” with the key
pair (7, 2).
Example 3.10
35. 3.2.1 Continued
Use the affine cipher to decrypt the message “ZEBBW” with the
key pair (7, 2) in modulus 26.
Example 3.11
Solution
The additive cipher is a special case of an affine cipher in which
k1 = 1. The multiplicative cipher is a special case of affine cipher in
which k2 = 0.
Example 3.12
36. 3.2.1 Continued
Because additive, multiplicative, and affine ciphers have small key
domains, they are very vulnerable to brute-force attack.
Monoalphabetic Substitution Cipher
A better solution is to create a mapping between each plaintext
character and the corresponding ciphertext character. Alice and
Bob can agree on a table showing the mapping for each character.
Figure 3.12 An example key for monoalphabetic substitution cipher
37. 3.2.1 Continued
We can use the key in Figure 3.12 to encrypt the message
Example 3.13
The ciphertext is
38. 3.2.2 Polyalphabetic Ciphers
In polyalphabetic substitution, each occurrence of a
character may have a different substitute. The
relationship between a character in the plaintext to a
character in the ciphertext is one-to-many.
Autokey Cipher
39. 3.2.2 Continued
Assume that Alice and Bob agreed to use an autokey cipher with
initial key value k1 = 12. Now Alice wants to send Bob the message
“Attack is today”. Enciphering is done character by character.
Example 3.14
40. Playfair Cipher
• Not even the large number of keys in a
monoalphabetic cipher provides security
• One approach to improving security was to
encrypt multiple letters
• Playfair Cipher is an example
41. Playfair Key Matrix
• 5X5 matrix of letters based on a keyword
• Fill in letters of keyword (sans duplicates)
• Fill rest of matrix with other letters
• Eg. using the keyword MONARCHY
42. Encrypting and Decrypting
Plaintext is encrypted two letters at a time
1. If a pair is a repeated letter, insert filler like 'X’
2. If both letters fall in the same row, replace each with
letter to right (wrapping back to start from end)
3. If both letters fall in the same column, replace each
with the letter below it (again wrapping to top from
bottom)
4. Otherwise each letter is replaced by the letter in the
43. Playfair Key Matrix
• Eg. Using the keyword MONARCHY
• Encrypt: Ballon -> Ba lx lo nx
• Cipher: IB SU PM AW
M O N A R
C H Y B D
E F G I/J K
L P Q S T
U V W X Z
44. 3.2.2 Continued
Playfair Cipher
Figure 3.13 An example of a secret key in the Playfair cipher
Let us encrypt the plaintext “hello” using the key in Figure 3.13.
Example 3.15
45. Security of Playfair Cipher
• Much improved over monoalphabetic
• Since have 26 x 26 = 676 digrams
• Would need a 676 entry frequency table to analyse
(verses 26 for a monoalphabetic)
• Correspondingly more ciphertext
• Was widely used for many years
– eg. by US & British military in WW1
• It can be broken, given a few hundred letters
46. Vigenère Cipher
• Simplest polyalphabetic substitution cipher
• Effectively multiple caesar ciphers
• Key is multiple letters long K = k1 k2 ... kd
• ith letter specifies ith alphabet to use
• Use each alphabet in turn
• Repeat from start after d letters in message
• Decryption simply works in reverse
48. 3.2.2 Continued
Using Example 3.18, we can say that the additive cipher is a
special case of Vigenere cipher in which m = 1.
Example 3.18
Table 3.3
A Vigenere Tableau
49.
50. 3.2.2 Continued
Hill Cipher
Figure 3.15 Key in the Hill cipher
The key matrix in the Hill cipher needs to
have a multiplicative inverse.
Note
51.
52.
53.
54.
55.
56.
57. 3.2.2 Continued
One of the goals of cryptography is perfect secrecy. A
study by Shannon has shown that perfect secrecy can be
achieved if each plaintext symbol is encrypted with a key
randomly chosen from a key domain. This idea is used in
a cipher called one-time pad, invented by Vernam.
One-Time Pad
60. 3-3 TRANSPOSITION CIPHERS
A transposition cipher does not substitute one symbol for
another, instead it changes the location of the symbols.
3.3.1 Keyless Transposition Ciphers
3.3.2 Keyed Transposition Ciphers
3.3.3 Combining Two Approaches
Topics discussed in this section:
A transposition cipher reorders symbols.
Note
61. 3.3.1 Keyless Transposition Ciphers
Simple transposition ciphers, which were used in the
past, are keyless.
A good example of a keyless cipher using the first method is the
rail fence cipher. The ciphertext is created reading the pattern row
by row. For example, to send the message “Meet me at the park”
to Bob, Alice writes
Example 3.22
She then creates the ciphertext “MEMATEAKETETHPR”.
62. 3.3.1 Continued
Alice and Bob can agree on the number of columns and use the
second method. Alice writes the same plaintext, row by row, in a
table of four columns.
Example 3.23
She then creates the ciphertext “MMTAEEHREAEKTTP”.
63. 3.3.1 Continued
The cipher in Example 3.23 is actually a transposition cipher. The
following shows the permutation of each character in the plaintext
into the ciphertext based on the positions.
Example 3.24
The second character in the plaintext has moved to the fifth
position in the ciphertext; the third character has moved to the
ninth position; and so on. Although the characters are permuted,
there is a pattern in the permutation: (01, 05, 09, 13), (02, 06, 10,
13), (03, 07, 11, 15), and (08, 12). In each section, the difference
between the two adjacent numbers is 4.
64. 3.3.2 Keyed Transposition Ciphers
The keyless ciphers permute the characters by using
writing plaintext in one way and reading it in another
way The permutation is done on the whole plaintext to
create the whole ciphertext. Another method is to divide
the plaintext into groups of predetermined size, called
blocks, and then use a key to permute the characters in
each block separately.
65. 3.3.2 Continued
Alice needs to send the message “Enemy attacks tonight” to Bob..
Example 3.25
The key used for encryption and decryption is a permutation key,
which shows how the character are permuted.
The permutation yields
67. Figure 3.22 Encryption/decryption keys in transpositional ciphers
3.3.3 Continued
Keys
In Example 3.27, a single key was used in two directions for the
column exchange: downward for encryption, upward for
decryption. It is customary to create two keys.
68. Figure 3.23 Key inversion in a transposition cipher
3.3.3 Continued
69. 3.3.3 Continued
Using Matrices
We can use matrices to show the encryption/decryption process for
a transposition cipher.
Figure 3.24 Representation of the key as a matrix in the transposition cipher
Example 3.27
70. Figure 3.24 Representation of the key as a matrix in the transposition cipher
3.3.3 Continued
Figure 3.24 shows the encryption process. Multiplying the 4 × 5
plaintext matrix by the 5 × 5 encryption key gives the 4 × 5
ciphertext matrix.
Example 3.27