This document provides a 3-paragraph summary of a lecture on cryptography:
Block ciphers encrypt blocks of plaintext into ciphertext using symmetric encryption algorithms and cryptographic keys. The lecture discusses block cipher modes of operation like Electronic Codebook (ECB), Cipher Block Chaining (CBC), and Counter mode (CTR) that extend block ciphers to encrypt arbitrarily long messages. ECB encrypts each block independently while CBC and CTR introduce dependencies between blocks to provide semantic security and prevent patterns in the ciphertext from revealing the plaintext. The lecture also covers cryptographic primitives like the Data Encryption Standard (DES) and the Advanced Encryption Standard (AES) and analyzes their security and performance.
This chapter discusses cryptographic tools used for encryption and authentication. Symmetric encryption uses a shared secret key to encrypt and decrypt messages, providing confidentiality. Public key encryption uses different public and private keys, allowing users to securely communicate and authenticate digitally. Secure hash functions and digital signatures provide message integrity and authentication without encryption. Random numbers are also important for generating keys and initializing encryption algorithms.
This document discusses cryptographic security. It defines informational and computational security, and explains how security is quantified in bits based on the difficulty of cracking a cipher. The document also covers achieving security through provable security via mathematical proofs or heuristic evidence from failed attacks. Additionally, it discusses generating keys randomly or from passwords, and protecting keys through wrapping or hardware tokens. Potential issues like incorrect security proofs, legacy support with short keys, and implementation flaws are also noted.
This document discusses public key cryptography and the RSA algorithm. It begins by outlining some misconceptions about public key encryption. It then provides an overview of the key concepts behind public key cryptosystems, including the use of public and private key pairs to enable encryption, digital signatures, and key exchange. The document goes on to provide detailed explanations of the RSA algorithm, including how it uses large prime numbers and modular arithmetic to encrypt and decrypt messages securely. It discusses the security of the RSA algorithm and analyzes approaches for attacking it, such as brute force key searching and mathematical attacks based on factoring the private key.
This document provides an overview of public key cryptography and the RSA algorithm. It discusses how public key cryptography solves issues with symmetric key distribution and digital signatures by using separate public and private keys. The RSA algorithm is then explained, including how key pairs are generated, how encryption and decryption work using modular exponentiation, and an example of computing keys and encrypting a message.
For a college course -- CNIT 140: "Cryptography for Computer Networks" at City College San Francisco
Instructor: Sam Bowne
More info: https://samsclass.info/141/141_S19.shtml
Based on "Serious Cryptography: A Practical Introduction to Modern Encryption", by Jean-Philippe Aumasson, No Starch Press (November 6, 2017), ISBN-10: 1593278268 ISBN-13: 978-1593278267
Public key cryptography uses two keys - a public key that can encrypt messages but not decrypt them, and a private key that can decrypt messages but not encrypt them. The RSA algorithm is a commonly used public key cryptosystem. It works by having users generate a public/private key pair using large prime numbers, then messages can be encrypted with the public key and decrypted with the private key. The security of RSA relies on the difficulty of factoring large numbers.
Symmetric Cipher Model,BruteForce attack, Cryptanalysis,Advantages of Symmetric cryptosystem,Model of conventional Encryption, model of conventional cryptosystem,Cryptography,Ciphertext,Plaintext,Decryption algorithm,Diadvantages of Symmetric Cryptosystem,Types of attacks on encrypted messages,Average time required for exhaustive key search
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.
This chapter discusses cryptographic tools used for encryption and authentication. Symmetric encryption uses a shared secret key to encrypt and decrypt messages, providing confidentiality. Public key encryption uses different public and private keys, allowing users to securely communicate and authenticate digitally. Secure hash functions and digital signatures provide message integrity and authentication without encryption. Random numbers are also important for generating keys and initializing encryption algorithms.
This document discusses cryptographic security. It defines informational and computational security, and explains how security is quantified in bits based on the difficulty of cracking a cipher. The document also covers achieving security through provable security via mathematical proofs or heuristic evidence from failed attacks. Additionally, it discusses generating keys randomly or from passwords, and protecting keys through wrapping or hardware tokens. Potential issues like incorrect security proofs, legacy support with short keys, and implementation flaws are also noted.
This document discusses public key cryptography and the RSA algorithm. It begins by outlining some misconceptions about public key encryption. It then provides an overview of the key concepts behind public key cryptosystems, including the use of public and private key pairs to enable encryption, digital signatures, and key exchange. The document goes on to provide detailed explanations of the RSA algorithm, including how it uses large prime numbers and modular arithmetic to encrypt and decrypt messages securely. It discusses the security of the RSA algorithm and analyzes approaches for attacking it, such as brute force key searching and mathematical attacks based on factoring the private key.
This document provides an overview of public key cryptography and the RSA algorithm. It discusses how public key cryptography solves issues with symmetric key distribution and digital signatures by using separate public and private keys. The RSA algorithm is then explained, including how key pairs are generated, how encryption and decryption work using modular exponentiation, and an example of computing keys and encrypting a message.
For a college course -- CNIT 140: "Cryptography for Computer Networks" at City College San Francisco
Instructor: Sam Bowne
More info: https://samsclass.info/141/141_S19.shtml
Based on "Serious Cryptography: A Practical Introduction to Modern Encryption", by Jean-Philippe Aumasson, No Starch Press (November 6, 2017), ISBN-10: 1593278268 ISBN-13: 978-1593278267
Public key cryptography uses two keys - a public key that can encrypt messages but not decrypt them, and a private key that can decrypt messages but not encrypt them. The RSA algorithm is a commonly used public key cryptosystem. It works by having users generate a public/private key pair using large prime numbers, then messages can be encrypted with the public key and decrypted with the private key. The security of RSA relies on the difficulty of factoring large numbers.
Symmetric Cipher Model,BruteForce attack, Cryptanalysis,Advantages of Symmetric cryptosystem,Model of conventional Encryption, model of conventional cryptosystem,Cryptography,Ciphertext,Plaintext,Decryption algorithm,Diadvantages of Symmetric Cryptosystem,Types of attacks on encrypted messages,Average time required for exhaustive key search
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.
This document provides an overview of cryptography concepts including symmetric and asymmetric key algorithms, cryptographic hashes, and tools for cryptanalysis. It defines common terminology like plaintext, ciphertext, encryption, and decryption. Symmetric algorithms discussed include the Vernam cipher, A5/1, DES, AES, and RC4. Asymmetric algorithms covered are RSA and Diffie-Hellman key exchange. Cryptographic hashes like MD5 and SHA-1 are also summarized along with resources for cryptanalysis.
This document provides an overview of cryptography concepts including symmetric and asymmetric key algorithms, cryptographic hashes, and tools for cryptanalysis. It defines common terminology like plaintext, ciphertext, encryption, and decryption. Symmetric algorithms discussed include the Vernam cipher, A5/1, DES, AES, and RC4. Asymmetric algorithms covered are RSA and Diffie-Hellman key exchange. Cryptographic hashes like MD5 and SHA-1 are also summarized along with resources for cryptanalysis.
Symmetric encryption uses the same key for both encryption and decryption. Common symmetric algorithms include DES, Triple DES, and AES. DES encrypts data in 64-bit blocks using a 56-bit key. Triple DES applies DES three times with three different keys to strengthen it against attacks. AES has a variable block size of 128 bits and key size of 128, 192, or 256 bits. It performs multiple rounds of substitution and permutation functions to encrypt the data securely.
The document discusses symmetric encryption. The most popular symmetric encryption standard today is AES, which uses 128, 192, or 256-bit keys to encrypt 128-bit blocks of plaintext. Other symmetric algorithms include Blowfish, RC4, 3DES, and IDEA. Symmetric algorithms are fast and used when performance is important. The same key is used for both encryption and decryption. Modes like CBC, CFB, OFB, and CTR can be used. Authentication can be provided by modes like GCM and GMAC. While theoretical attacks on AES exist, current attacks are not practical and a brute-force attack would take a long time. Side channel attacks target specific implementations rather than the AES algorithm itself.
This document discusses post-quantum cryptography and code-based cryptography as a potential solution. It provides an overview of cryptography, both symmetric and asymmetric, and explains how quantum computers could break many current systems by solving mathematical problems efficiently. Code-based cryptography is introduced as an alternative that does not rely on these vulnerable problems. The McEliece cryptosystem and Staircase code-based schemes are described. The document then outlines a project to implement a random split of Staircase codes to thwart information set decoding attacks, including researching the topic, developing implementations, validating the approach works as intended, and verifying the results against benchmarks. It emphasizes that development should begin now to have solutions ready when needed.
The document provides information about symmetric encryption models and cryptanalysis techniques. It discusses the basic components of symmetric encryption including plain text, cipher text, cipher, key, encrypting and decrypting functions. It also explains brute force attacks and different types of attacks on encrypted messages like ciphertext-only, known plaintext, chosen plaintext and chosen ciphertext attacks. The document further discusses the characteristics of the AES algorithm and the key distribution process for symmetric encryption.
Cryptography and network security Nit701Amit Pathak
Cryptography and network security descries the security parameter with the help of public and private key. Digital signature is one of the most important area which we apply in our daily life for transferring the data.
Cryptography is the process of securing communication and information. This document discusses several methods of cryptography including symmetric and public key cryptography. It provides examples of classical cryptography techniques like the Caesar cipher, transposition cipher, substitution cipher and the Vigenere cipher. It also discusses modern symmetric key algorithms like the Data Encryption Standard (DES) and the Advanced Encryption Standard (AES) which are widely used today. The one-time pad is described as theoretically unbreakable but impractical to implement. Block ciphers and padding methods are also summarized.
This presentation introduces the Basics of Cryptography and Network Security concepts. Heavily derived from content from William Stalling's book with the same title.
1. Cryptography is the broadest security tool available that allows for secure communication over insecure mediums. It provides confidentiality through encryption.
2. Encryption algorithms use a set of keys to encrypt messages into ciphertexts and decrypt ciphertexts back into messages. The encryption and decryption functions must be efficiently computable.
3. Symmetric encryption uses the same key to encrypt and decrypt, while asymmetric encryption uses a public key to encrypt and a private key to decrypt, allowing for secure communication without having to share private keys.
This document summarizes symmetric cryptography and several symmetric encryption algorithms. It describes how symmetric cryptography uses the same secret key for encryption and decryption. It then discusses the basics of block ciphers and stream ciphers, providing examples like DES, AES, and RC4. It also explains the concepts of iterated block ciphers and Feistel ciphers. In particular, it provides detailed descriptions of the DES algorithm, including its key schedule, round structure, S-boxes, and how it can be used as a Feistel cipher for both encryption and decryption.
Information and data security block cipher and the data encryption standard (...Mazin Alwaaly
Block ciphers like DES encrypt data in fixed-size blocks and use symmetric encryption keys. DES is a 64-bit block cipher that uses a 56-bit key. It employs a Feistel network structure with 16 rounds to provide diffusion and confusion of the plaintext block. Each round uses subkey-dependent substitution boxes and permutation functions. While DES was widely adopted, cryptanalysis techniques showed it could be broken with less than 256 tries, making the key size too short by modern standards.
- Public key cryptography uses asymmetric encryption involving two keys - a public key to encrypt and a private key to decrypt. This allows secure communication without pre-sharing keys.
- RSA was the first practical public key cryptosystem, based on the difficulty of factoring large prime numbers. It allows encryption with a public key and decryption with a private key.
- Diffie-Hellman key exchange allows two parties to jointly establish a shared secret key over an insecure channel without any prior secrets. This key can then be used to encrypt subsequent communications.
Securing Text Messages Application Using MEDZatulNadia
Implementing hybrid security algorithm in securing data.
-Introduction
-Problem statement
-Objective
-Process model
-Public key cryptosystem
-Data model
-Proposed model
-Encryption and decryption process
-Proof of concept
* netbeans 8.1 *xampp *database
*java programming language
-Expected results
*performance for key generation, encryption and decryption
*graph
-References
Block ciphers like AES encrypt data in fixed-size blocks and use cryptographic keys and rounds of processing to encrypt the data securely. AES is the current standard, using 128-bit blocks and keys of 128, 192, or 256 bits. Modes of operation like ECB, CBC, CTR are used to handle full messages. ECB is insecure as identical plaintext blocks produce identical ciphertext, while CBC and CTR provide security if nonces and IVs are not reused. Implementation details like padding and side channels must be handled carefully to prevent attacks.
This document discusses network security and honeypot techniques. It provides an overview of honeypots, including their value in learning about blackhat hacking tools and techniques. It describes different types of honeypots, including first and second generation honeypots, and how they aim to gather information while being difficult to detect. The document also briefly mentions honeynets and the Honeynet Project, an organization dedicated to honeypot research.
This document provides an overview and introduction to a cryptography course. It discusses how cryptography has evolved from a historical focus on secret codes to a modern scientific field. The document outlines the course goals of understanding theoretical foundations and applying a "crypto mindset". It also discusses necessary administrative details like the textbook, assignments, exams, and contact information for the professor and TAs.
This document discusses public key cryptography and the RSA algorithm. It begins by explaining the limitations of private key cryptography and how public key cryptography addresses issues like key distribution and digital signatures. It then describes how RSA works, using two keys - a public key for encryption and a private key for decryption. It explains the key generation process, how messages are encrypted and decrypted, and discusses the mathematical principles and security of the RSA algorithm.
Predictably Improve Your B2B Tech Company's Performance by Leveraging DataKiwi Creative
Harness the power of AI-backed reports, benchmarking and data analysis to predict trends and detect anomalies in your marketing efforts.
Peter Caputa, CEO at Databox, reveals how you can discover the strategies and tools to increase your growth rate (and margins!).
From metrics to track to data habits to pick up, enhance your reporting for powerful insights to improve your B2B tech company's marketing.
- - -
This is the webinar recording from the June 2024 HubSpot User Group (HUG) for B2B Technology USA.
Watch the video recording at https://youtu.be/5vjwGfPN9lw
Sign up for future HUG events at https://events.hubspot.com/b2b-technology-usa/
This document provides an overview of cryptography concepts including symmetric and asymmetric key algorithms, cryptographic hashes, and tools for cryptanalysis. It defines common terminology like plaintext, ciphertext, encryption, and decryption. Symmetric algorithms discussed include the Vernam cipher, A5/1, DES, AES, and RC4. Asymmetric algorithms covered are RSA and Diffie-Hellman key exchange. Cryptographic hashes like MD5 and SHA-1 are also summarized along with resources for cryptanalysis.
This document provides an overview of cryptography concepts including symmetric and asymmetric key algorithms, cryptographic hashes, and tools for cryptanalysis. It defines common terminology like plaintext, ciphertext, encryption, and decryption. Symmetric algorithms discussed include the Vernam cipher, A5/1, DES, AES, and RC4. Asymmetric algorithms covered are RSA and Diffie-Hellman key exchange. Cryptographic hashes like MD5 and SHA-1 are also summarized along with resources for cryptanalysis.
Symmetric encryption uses the same key for both encryption and decryption. Common symmetric algorithms include DES, Triple DES, and AES. DES encrypts data in 64-bit blocks using a 56-bit key. Triple DES applies DES three times with three different keys to strengthen it against attacks. AES has a variable block size of 128 bits and key size of 128, 192, or 256 bits. It performs multiple rounds of substitution and permutation functions to encrypt the data securely.
The document discusses symmetric encryption. The most popular symmetric encryption standard today is AES, which uses 128, 192, or 256-bit keys to encrypt 128-bit blocks of plaintext. Other symmetric algorithms include Blowfish, RC4, 3DES, and IDEA. Symmetric algorithms are fast and used when performance is important. The same key is used for both encryption and decryption. Modes like CBC, CFB, OFB, and CTR can be used. Authentication can be provided by modes like GCM and GMAC. While theoretical attacks on AES exist, current attacks are not practical and a brute-force attack would take a long time. Side channel attacks target specific implementations rather than the AES algorithm itself.
This document discusses post-quantum cryptography and code-based cryptography as a potential solution. It provides an overview of cryptography, both symmetric and asymmetric, and explains how quantum computers could break many current systems by solving mathematical problems efficiently. Code-based cryptography is introduced as an alternative that does not rely on these vulnerable problems. The McEliece cryptosystem and Staircase code-based schemes are described. The document then outlines a project to implement a random split of Staircase codes to thwart information set decoding attacks, including researching the topic, developing implementations, validating the approach works as intended, and verifying the results against benchmarks. It emphasizes that development should begin now to have solutions ready when needed.
The document provides information about symmetric encryption models and cryptanalysis techniques. It discusses the basic components of symmetric encryption including plain text, cipher text, cipher, key, encrypting and decrypting functions. It also explains brute force attacks and different types of attacks on encrypted messages like ciphertext-only, known plaintext, chosen plaintext and chosen ciphertext attacks. The document further discusses the characteristics of the AES algorithm and the key distribution process for symmetric encryption.
Cryptography and network security Nit701Amit Pathak
Cryptography and network security descries the security parameter with the help of public and private key. Digital signature is one of the most important area which we apply in our daily life for transferring the data.
Cryptography is the process of securing communication and information. This document discusses several methods of cryptography including symmetric and public key cryptography. It provides examples of classical cryptography techniques like the Caesar cipher, transposition cipher, substitution cipher and the Vigenere cipher. It also discusses modern symmetric key algorithms like the Data Encryption Standard (DES) and the Advanced Encryption Standard (AES) which are widely used today. The one-time pad is described as theoretically unbreakable but impractical to implement. Block ciphers and padding methods are also summarized.
This presentation introduces the Basics of Cryptography and Network Security concepts. Heavily derived from content from William Stalling's book with the same title.
1. Cryptography is the broadest security tool available that allows for secure communication over insecure mediums. It provides confidentiality through encryption.
2. Encryption algorithms use a set of keys to encrypt messages into ciphertexts and decrypt ciphertexts back into messages. The encryption and decryption functions must be efficiently computable.
3. Symmetric encryption uses the same key to encrypt and decrypt, while asymmetric encryption uses a public key to encrypt and a private key to decrypt, allowing for secure communication without having to share private keys.
This document summarizes symmetric cryptography and several symmetric encryption algorithms. It describes how symmetric cryptography uses the same secret key for encryption and decryption. It then discusses the basics of block ciphers and stream ciphers, providing examples like DES, AES, and RC4. It also explains the concepts of iterated block ciphers and Feistel ciphers. In particular, it provides detailed descriptions of the DES algorithm, including its key schedule, round structure, S-boxes, and how it can be used as a Feistel cipher for both encryption and decryption.
Information and data security block cipher and the data encryption standard (...Mazin Alwaaly
Block ciphers like DES encrypt data in fixed-size blocks and use symmetric encryption keys. DES is a 64-bit block cipher that uses a 56-bit key. It employs a Feistel network structure with 16 rounds to provide diffusion and confusion of the plaintext block. Each round uses subkey-dependent substitution boxes and permutation functions. While DES was widely adopted, cryptanalysis techniques showed it could be broken with less than 256 tries, making the key size too short by modern standards.
- Public key cryptography uses asymmetric encryption involving two keys - a public key to encrypt and a private key to decrypt. This allows secure communication without pre-sharing keys.
- RSA was the first practical public key cryptosystem, based on the difficulty of factoring large prime numbers. It allows encryption with a public key and decryption with a private key.
- Diffie-Hellman key exchange allows two parties to jointly establish a shared secret key over an insecure channel without any prior secrets. This key can then be used to encrypt subsequent communications.
Securing Text Messages Application Using MEDZatulNadia
Implementing hybrid security algorithm in securing data.
-Introduction
-Problem statement
-Objective
-Process model
-Public key cryptosystem
-Data model
-Proposed model
-Encryption and decryption process
-Proof of concept
* netbeans 8.1 *xampp *database
*java programming language
-Expected results
*performance for key generation, encryption and decryption
*graph
-References
Block ciphers like AES encrypt data in fixed-size blocks and use cryptographic keys and rounds of processing to encrypt the data securely. AES is the current standard, using 128-bit blocks and keys of 128, 192, or 256 bits. Modes of operation like ECB, CBC, CTR are used to handle full messages. ECB is insecure as identical plaintext blocks produce identical ciphertext, while CBC and CTR provide security if nonces and IVs are not reused. Implementation details like padding and side channels must be handled carefully to prevent attacks.
This document discusses network security and honeypot techniques. It provides an overview of honeypots, including their value in learning about blackhat hacking tools and techniques. It describes different types of honeypots, including first and second generation honeypots, and how they aim to gather information while being difficult to detect. The document also briefly mentions honeynets and the Honeynet Project, an organization dedicated to honeypot research.
This document provides an overview and introduction to a cryptography course. It discusses how cryptography has evolved from a historical focus on secret codes to a modern scientific field. The document outlines the course goals of understanding theoretical foundations and applying a "crypto mindset". It also discusses necessary administrative details like the textbook, assignments, exams, and contact information for the professor and TAs.
This document discusses public key cryptography and the RSA algorithm. It begins by explaining the limitations of private key cryptography and how public key cryptography addresses issues like key distribution and digital signatures. It then describes how RSA works, using two keys - a public key for encryption and a private key for decryption. It explains the key generation process, how messages are encrypted and decrypted, and discusses the mathematical principles and security of the RSA algorithm.
Predictably Improve Your B2B Tech Company's Performance by Leveraging DataKiwi Creative
Harness the power of AI-backed reports, benchmarking and data analysis to predict trends and detect anomalies in your marketing efforts.
Peter Caputa, CEO at Databox, reveals how you can discover the strategies and tools to increase your growth rate (and margins!).
From metrics to track to data habits to pick up, enhance your reporting for powerful insights to improve your B2B tech company's marketing.
- - -
This is the webinar recording from the June 2024 HubSpot User Group (HUG) for B2B Technology USA.
Watch the video recording at https://youtu.be/5vjwGfPN9lw
Sign up for future HUG events at https://events.hubspot.com/b2b-technology-usa/
06-04-2024 - NYC Tech Week - Discussion on Vector Databases, Unstructured Data and AI
Round table discussion of vector databases, unstructured data, ai, big data, real-time, robots and Milvus.
A lively discussion with NJ Gen AI Meetup Lead, Prasad and Procure.FYI's Co-Found
The Ipsos - AI - Monitor 2024 Report.pdfSocial Samosa
According to Ipsos AI Monitor's 2024 report, 65% Indians said that products and services using AI have profoundly changed their daily life in the past 3-5 years.
Beyond the Basics of A/B Tests: Highly Innovative Experimentation Tactics You...Aggregage
This webinar will explore cutting-edge, less familiar but powerful experimentation methodologies which address well-known limitations of standard A/B Testing. Designed for data and product leaders, this session aims to inspire the embrace of innovative approaches and provide insights into the frontiers of experimentation!
ViewShift: Hassle-free Dynamic Policy Enforcement for Every Data LakeWalaa Eldin Moustafa
Dynamic policy enforcement is becoming an increasingly important topic in today’s world where data privacy and compliance is a top priority for companies, individuals, and regulators alike. In these slides, we discuss how LinkedIn implements a powerful dynamic policy enforcement engine, called ViewShift, and integrates it within its data lake. We show the query engine architecture and how catalog implementations can automatically route table resolutions to compliance-enforcing SQL views. Such views have a set of very interesting properties: (1) They are auto-generated from declarative data annotations. (2) They respect user-level consent and preferences (3) They are context-aware, encoding a different set of transformations for different use cases (4) They are portable; while the SQL logic is only implemented in one SQL dialect, it is accessible in all engines.
#SQL #Views #Privacy #Compliance #DataLake
Global Situational Awareness of A.I. and where its headedvikram sood
You can see the future first in San Francisco.
Over the past year, the talk of the town has shifted from $10 billion compute clusters to $100 billion clusters to trillion-dollar clusters. Every six months another zero is added to the boardroom plans. Behind the scenes, there’s a fierce scramble to secure every power contract still available for the rest of the decade, every voltage transformer that can possibly be procured. American big business is gearing up to pour trillions of dollars into a long-unseen mobilization of American industrial might. By the end of the decade, American electricity production will have grown tens of percent; from the shale fields of Pennsylvania to the solar farms of Nevada, hundreds of millions of GPUs will hum.
The AGI race has begun. We are building machines that can think and reason. By 2025/26, these machines will outpace college graduates. By the end of the decade, they will be smarter than you or I; we will have superintelligence, in the true sense of the word. Along the way, national security forces not seen in half a century will be un-leashed, and before long, The Project will be on. If we’re lucky, we’ll be in an all-out race with the CCP; if we’re unlucky, an all-out war.
Everyone is now talking about AI, but few have the faintest glimmer of what is about to hit them. Nvidia analysts still think 2024 might be close to the peak. Mainstream pundits are stuck on the wilful blindness of “it’s just predicting the next word”. They see only hype and business-as-usual; at most they entertain another internet-scale technological change.
Before long, the world will wake up. But right now, there are perhaps a few hundred people, most of them in San Francisco and the AI labs, that have situational awareness. Through whatever peculiar forces of fate, I have found myself amongst them. A few years ago, these people were derided as crazy—but they trusted the trendlines, which allowed them to correctly predict the AI advances of the past few years. Whether these people are also right about the next few years remains to be seen. But these are very smart people—the smartest people I have ever met—and they are the ones building this technology. Perhaps they will be an odd footnote in history, or perhaps they will go down in history like Szilard and Oppenheimer and Teller. If they are seeing the future even close to correctly, we are in for a wild ride.
Let me tell you what we see.
Natural Language Processing (NLP), RAG and its applications .pptxfkyes25
1. In the realm of Natural Language Processing (NLP), knowledge-intensive tasks such as question answering, fact verification, and open-domain dialogue generation require the integration of vast and up-to-date information. Traditional neural models, though powerful, struggle with encoding all necessary knowledge within their parameters, leading to limitations in generalization and scalability. The paper "Retrieval-Augmented Generation for Knowledge-Intensive NLP Tasks" introduces RAG (Retrieval-Augmented Generation), a novel framework that synergizes retrieval mechanisms with generative models, enhancing performance by dynamically incorporating external knowledge during inference.
Analysis insight about a Flyball dog competition team's performanceroli9797
Insight of my analysis about a Flyball dog competition team's last year performance. Find more: https://github.com/rolandnagy-ds/flyball_race_analysis/tree/main
2. CS555 Topic 4 2
Readings for This Lecture
• Required reading from
wikipedia
• Block Cipher
• Ciphertext
Indistinguishability
• Block cipher modes of
operation
3. Notation for Symmetric-key
Encryption
• A symmetric-key encryption scheme is comprised of
three algorithms
– Gen the key generation algorithm
• The algorithm must be probabilistic/randomized
• Output: a key k
– Enc the encryption algorithm
• Input: key k, plaintext m
• Output: ciphertext c := Enck(m)
– Dec the decryption algorithm
• Input: key k, ciphertext c
• Output: plaintext m := Deck(m)
CS555 Topic 4 3
Requirement: k m [ Deck(Enck(m)) = m ]
4. Randomized vs. Deterministic
Encryption
• Encryption can be randomized,
– i.e., same message, same key, running the encryption algorithm
twice results in two different ciphertexts
– E.g, Enck[m] = (r, PRNG[k||r]m), i.e., the ciphertext includes two
parts, a randomly generated r, and a second part
• Decryption is deterministic in the sense that
– For the same ciphertext and same key, running decryption
algorithm twice always results in the same plaintext
• Each key induces a one-to-many mapping from plaintext
space to ciphertext space
– Corollary: ciphertext space must be equal to or larger than
plaintext space
CS555 Topic 4 4
5. Towards Computational Security
• Perfect secrecy is too difficult to achieve.
• Computational security uses two relaxations:
– Security is preserved only against efficient
(computationally bounded) adversaries
• Adversary can only run in feasible amount of time
– Adversaries can potentially succeed with some very
small probability (that we can ignore the case it
actually happens)
• Two approaches to formalize computational
security: concrete and asymptotic
CS555 Topic 4 5
6. The Concrete Approach
• Quantifies the security by explicitly bounding the maximum
success probability of adversary running with certain time:
– “A scheme is (t,)-secure if every adversary running for
time at most t succeeds in breaking the scheme with
probability at most ”
– Example: a strong encryption scheme with n-bit keys
may be expected to be (t, t/2n)-secure.
• N=128, t=260, then = 2-68. (# of seconds since big
bang is 258)
• Makes more sense with symmetric encryption schemes
because they use fixed key lengths.
CS555 Topic 4 6
7. The Asymptotic Approach
• A cryptosystem has a security parameter
– E.g., number of bits in the RSA algorithm (1024,2048,…)
• Typically, the key length depends on the security parameter
– The bigger the security parameter, the longer the key, the more time
it takes to use the cryptosystem, and the more difficult it is to break
the scheme
• The crypto system must be efficient, i.e., runs in time
polynomial in the security parameter
• “A scheme is secure if every Probabilistic Polynomial Time
(PPT) algorithm succeeds in breaking the scheme with only
negligible probability”
– “negligible” roughly means goes to 0 exponentially fast as the
security parameter increases
CS555 Topic 4 7
8. Defining Security
• Desire “semantic security”, i.e., having access to
the ciphertext does not help adversary to
compute any function of the plaintext.
– Difficult to use
• Equivalent notion: Adversary cannot distinguish
between the ciphertexts of two plaintexts
CS555 Topic 4 11
9. Towards IND-CPA Security:
• Ciphertext Indistinguishability under a Chosen-Plaintext
Attack: Define the following IND-CPA experiment :
– Involving an Adversary and a Challenger
– Instantiated with an Adversary algorithm A, and an encryption
scheme = (Gen, Enc, Dec)
CS555 Topic 4 12
Challenger Adversary
k Gen()
b R {0,1}
chooses m0, m1 M
m0, m1
C=Enck[mb]
b’ {0,1}
Adversary wins if b=b’
Enck[]
10. The IND-CPA Experiment
Explained
• A k is generated by Gen()
• Adversary is given oracle access to Enck(),
– Oracle access: one gets its question answered without knowing any
additional information
• Adversary outputs a pair of equal-length messages m0 and
m1
• A random bit b is chosen, and adversary is given Enck(mb)
– Called the challenge ciphertext
• Adversary does any computation it wants, while still having
oracle access to Enck(), and outputs b’
• Adversary wins if b=b’
CS555 Topic 4 13
11. CPA-secure (aka IND-CPA
security)
• A encryption scheme = (Gen, Enc, Dec) has
indistinguishable encryption under a chosen-
plaintext attack (i.e., is IND-CPA secure) iff. for
all PPT adversary A, there exists a negligible
function negl such that
• Pr[A wins in IND-CPA experiment] ½ + negl(n)
• No deterministic encryption scheme is CPA-
secure. Why?
CS555 Topic 4 14
12. Another (Equivalent) Explanation
of IND-CPA Security
• Ciphertext indistinguishability under chosen plaintext attack (IND-CPA)
– Challenger chooses a random key K
– Adversary chooses a number of messages and obtains their ciphertexts
under key K
– Adversary chooses two equal-length messages m0 and m1, sends them to a
Challenger
– Challenger generates C=EK[mb], where b is a uniformly randomly chosen bit,
and sends C to the adversary
– Adversary outputs b’ and wins if b=b’
– Adversary advantage is | Pr[Adv wins] – ½ |
– Adversary should not have a non-negligible advantage
• E.g, Less than, e.g., 1/280 when the adversary is limited to certain amount of
computation;
• decreases exponentially with the security parameter (typically length of the key)
CS555 Topic 4 15
13. Intuition of IND-CPA security
• Perfect secrecy means that any plaintext is encrypted to
a given ciphertext with the same probability, i.e., given
any pair of M0 and M1, the probabilities that they are
encrypted into a ciphertext C are the same
– Hence no adversary can tell whether C is ciphertext of M0 or M1.
• IND-CPA means
– With bounded computational resources, the adversary cannot tell
which of M0 and M1 is encrypted in C
• Stream ciphers can be used to achieve IND-CPA security when the
underlying PRNG is cryptographically strong
– (i.e., generating sequences that cannot be distinguished from random,
even when related seeds are used)
CS555 Topic 4 16
14. Computational Security vs.
Information Theoretic Security
• If a cipher has only computational security, then
it can be broken by a brute force attack, e.g.,
enumerating all possible keys
– Weak algorithms can be broken with much less time
• How to prove computational security?
– Assume that some problems are hard (requires a lot of
computational resources to solve), then show that
breaking security means solving the problem
• Computational security is foundation of modern
cryptography.
CS555 Topic 4 17
15. CS555 Topic 4 20
Why Block Ciphers?
• One thread of defeating frequency analysis
– Use different keys in different locations
– Example: one-time pad, stream ciphers
• Another way to defeat frequency analysis
– Make the unit of transformation larger, rather than
encrypting letter by letter, encrypting block by block
– Example: block cipher
16. CS555 Topic 4 21
Block Ciphers
• An n-bit plaintext is encrypted to an n-bit
ciphertext
– P : {0,1}n
– C : {0,1}n
– K : {0,1}s
– E: K ×P C : Ek: a permutation on {0,1} n
– D: K ×C P : Dk is Ek
-1
– Block size: n
– Key size: s
17. CS555 Topic 4 22
Data Encryption Standard (DES)
• Designed by IBM, with modifications proposed by the
National Security Agency
• US national standard from 1977 to 2001
• De facto standard
• Block size is 64 bits;
• Key size is 56 bits
• Has 16 rounds
• Designed mostly for hardware implementations
– Software implementation is somewhat slow
• Considered insecure now
– vulnerable to brute-force attacks
• Triple DES: Ek3Dk2EK1(M) has 112-bit strength, but slow
18. CS555 Topic 4 23
Attacking Block Ciphers
• Types of attacks to consider
– known plaintext: given several pairs of plaintexts and
ciphertexts, recover the key (or decrypt another block
encrypted under the same key)
– how would chosen plaintext and chosen ciphertext be
defined?
• Standard attacks
– exhaustive key search
– dictionary attack
– differential cryptanalysis, linear cryptanalysis
• Side channel attacks.
DES’s main vulnerability is short key size.
19. Chosen-Plaintext Dictionary
Attacks Against Block Ciphers
• Construct a table with the following entries
– (K, EK[0]) for all possible key K
– Sort based on the second field (ciphertext)
– How much time does this take?
• To attack a new key K (under chosen message
attacks)
– Choose 0, obtain the ciphertext C, looks up in the
table, and finds the corresponding key
– How much time does this step take?
• Trade off space for time
CS555 Topic 4 24
20. CS555 Topic 4 25
Advanced Encryption Standard
• In 1997, NIST made a formal call for algorithms stipulating
that the AES would specify an unclassified, publicly
disclosed encryption algorithm, available royalty-free,
worldwide.
• Goal: replace DES for both government and private-sector
encryption.
• The algorithm must implement symmetric key cryptography
as a block cipher and (at a minimum) support block sizes of
128-bits and key sizes of 128-, 192-, and 256-bits.
• In 1998, NIST selected 15 AES candidate algorithms.
• On October 2, 2000, NIST selected Rijndael (invented by
Joan Daemen and Vincent Rijmen) to as the AES.
21. CS555 Topic 4 26
AES Features
• Designed to be efficient in both hardware
and software across a variety of platforms.
• Block size: 128 bits
• Variable key size: 128, 192, or 256 bits.
• No known weaknesses
22. Need for Encryption Modes
• A block cipher encrypts only one block
• Needs a way to extend it to encrypt an arbitrarily
long message
• Want to ensure that if the block cipher is secure,
then the encryption is secure
• Aims at providing Semantic Security (IND-CPA)
assuming that the underlying block ciphers are
strong
CS555 Topic 4 27
23. CS555 Topic 4 28
Block Cipher Encryption Modes: ECB
• Message is broken into independent blocks;
• Electronic Code Book (ECB): each block
encrypted separately.
• Encryption: ci = Ek(xi)
• Decrytion: xi = Dk(ci)
24. CS555 Topic 4 29
Properties of ECB
• Deterministic:
– the same data block gets encrypted the same way,
• reveals patterns of data when a data block repeats
– when the same key is used, the same message is
encrypted the same way
• Usage: not recommended to encrypt more than
one block of data
• How to break the semantic security (IND-CPA)
of a block cipher with ECB?
25. CS555 Topic 4 30
DES Encryption Modes: CBC
• Cipher Block Chaining (CBC):
– Uses a random Initial Vector (IV)
– Next input depends upon previous output
Encryption: Ci= Ek (MiCi-1), with C0=IV
Decryption: Mi= Ci-1Dk(Ci), with C0=IV
M1 M2 M3
IV
Ek
C1
Ek
C2
Ek
C3
C0
26. CS555 Topic 4 31
Properties of CBC
• Randomized encryption: repeated text gets mapped to
different encrypted data.
– can be proven to provide IND-CPA assuming that the block cipher
is secure (i.e., it is a Pseudo Random Permutation (PRP)) and that
IV’s are randomly chosen and the IV space is large enough (at
least 64 bits)
• Each ciphertext block depends on all preceding plaintext
blocks.
• Usage: chooses random IV and protects the integrity of
IV
– The IV is not secret (it is part of ciphertext)
– The adversary cannot control the IV
27. Encryption Modes: CTR
• Counter Mode (CTR): Defines a stream cipher using a
block cipher
– Uses a random IV, known as the counter
– Encryption: C0=IV, Ci =Mi Ek[IV+i]
– Decryption: IV=C0, Mi =Ci Ek[IV+i]
CS555 Topic 4 32
M2
IV
Ek
C2
C0
IV+2
M3
Ek
C3
IV+3
M1
Ek
C1
IV+1
28. CS555 Topic 4 33
Properties of CTR
• Gives a stream cipher from a block cipher
• Randomized encryption:
– when starting counter is chosen randomly
• Random Access: encryption and decryption of
a block can be done in random order, very
useful for hard-disk encryption.
– E.g., when one block changes, re-encryption only
needs to encrypt that block. In CBC, all later
blocks also need to change