PPT-Cryptography Lecture 8 Pseudorandom functions

Keyed functions Let F 01 x 01 01 be an efficient deterministic algorithm Define F k x Fk x The first input is called the key A ssume F is length preserving. uoagr Abstract Pseudorandom sequences have many applications in cryp tography and spread spectrum communications In this dissertation on one hand we develop tools for assessing the randomness of a sequence and on the other hand we propose new constru Thomas . Holenstein. Iftach Haitner. Salil Vadhan. Hoeteck Wee. Joint With. Omer Reingold. Cryptography. Rich array of . applications and . powerful . implementations.. In some cases (. e.g. Zero-Knowledge), . CS 465. Last Updated. : . Aug 25, 2015. Outline. Provide a brief historical background of cryptography. Introduce definitions and high-level description of four cryptographic primitives we will learn about this semester. Raghu Meka (IAS). Parikshit Gopalan, Omer Reingold (MSR-SVC) Luca Trevian (Stanford), Salil Vadhan (Harvard). Can we generate random bits?. Can we generate random bits?. Pseudorandom Generators. Stretch bits to fool a class of “test functions” . 3b. . Pseudorandomness. .. B. ased on: Jonathan . Katz and Yehuda . Lindell. . Introduction . to . Modern Cryptography. 2. Pseudorandomness. An introduction. A distribution . D. is pseudorandom if no PPT . CS. . 111. Operating . Systems . Peter Reiher. . Outline. Basic concepts in computer security. Design principles for security. Important security tools for operating systems. Access control. Cryptography and operating systems. Josh Benaloh. Tolga Acar. Fall 2016. November 8, 2016. Practical Aspects of Modern Cryptography. 1. What is Money?. 106 billion people lived. 94% are dead. Most of the world’s wealth made after 1800. Vadim . Lyubashevsky. Cryptography. Allows for secure communication in the presence of malicious parties. 2. Cryptography. Allows for secure communication in the presence of malicious parties. 3. Cryptography. Ali. Neslisah Torosdagli . Josiah . Wong . Introduction. Cryptography. : . the field of study that is related to encoded information. The name comes from combining two Greek words that mean “hidden word”. . 1. Administrative Note. Professor Blocki is traveling and will be back on Wednesday. . E-mail: . jblocki@purdue.edu. . Thanks to Professor Spafford for covering the first lecture!. 2. https://www.cs.purdue.edu/homes/jblocki/courses/555_Spring17/index.html. Cryptography Lecture 8 Pseudorandom functions Keyed functions Let F: {0,1} * x {0,1} *  {0,1} * be an efficient, deterministic algorithm Define F k (x) = F(k, x) The first input is called the k. c. m. c. . . . Enc. k. (m). k. m. 1. c. 1. . . . Enc. k. (m. 1. ). m. 2. c. 2. . . . Enc. k. (m. 2. ). c. 1. c. 2. Is the threat model too strong?. In practice, there are many ways an attacker can . The . art and science of concealing the messages to introduce secrecy in . information security . is recognized as cryptography. .. The word ‘cryptography’ was coined by combining two Greek words, ‘Krypto’ . . (PRGs). Let G be an efficient, deterministic algorithm . that expands a . short . seed. . into a . longer . output. Specifically, let |G(x)| = p(|x|). G is a PRG if: when the distribution of x is uniform, the distribution of G(x) is “indistinguishable from uniform”.