PPT-Cryptography Lecture 13

Cryptography Lecture 13 Hash functions Hash functions Cryptographic hash function deterministic function mapping arbitrary length inputs to a short fixedlength output Hash functions can be keyed. However computational aspects of lattices were not investigated much until the early 1980s when they were successfully employed for breaking several proposed cryptosystems among many other applications It was not until the late 1990s that lattices w 897 Special Topics in Cryptography Instructors Ran Canetti and Ron Rivest Lecture 25 PairingBased Cryptography May 5 2004 Scribe Ben Adida 1 Introduction The 64257eld of PairingBased Cryptography has exploded Intro to IT. . COSC1078 Introduction to Information Technology. . Lecture 22. Internet Security. James Harland. james.harland@rmit.edu.au. Lecture 20: Internet. Intro to IT. . Introduction to IT. 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. Algorithms. Scott Chappell. What is Cryptography?. Definition: the art of writing or solving codes. Basic Encryption Methods. Caesar Shift. Simple Substitution Cipher. Fun to use, but are easily cracked by computers and even by humans. Week two!. The Game. 8 groups of 2. 5 rounds. Math 1. Modern history. Math 2. Computer Programming. Analyzing and comparing Cryptosystems. 10 questions per round. Each question is worth 1 point. Math Round 1. CSE3002 – History of Computing. Group A: Daniel . Bownoth. , Michael Feldman, Dalton Miner, Ashley Sanders. Encryption. The process of securing information by transforming it into code.. Encrypted data must be deciphered, or . 1. Part I: Crypto. Chapter 2: Crypto Basics. MXDXBVTZWVMXNSPBQXLIMSCCSGXSCJXBOVQXCJZMOJZCVC. TVWJCZAAXZBCSSCJXBQCJZCOJZCNSPOXBXSBTVWJC. JZDXGXXMOZQMSCSCJXBOVQXCJZMOJZCNSPJZHGXXMOSPLH. JZDXZAAXZBXHCSCJXTCSGXSCJXBOVQX. Symmetric Encryption. Key exchange . Public-Key Cryptography. Key exchange. Certification . Why Cryptography. General Security Goal. - . Confidentiality . (. fortrolig. ). - . End-point Authentication . 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. We have discussed two classes of cryptographic assumptions. Factoring-based (factoring, RSA assumptions). Dlog. -based (. dlog. , CDH, and DDH assumptions). In two classes of groups. A. ll these problems are believed to be “hard,” i.e., to have no polynomial-time algorithms. Cyclic group G of order q with generator g.  G.  . G = {g. 0. , g. 1. , …, g. q-1. }. For any h .  G, define . log. g. h .  {0, …, q-1} as. . log. g. h = x  . 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’ . Crypto is amazing. Can do things that initially seem impossible. Crypto is important. It impacts each of us every day. Crypto is fun!. Deep theory. Attackers’ mindset. Necessary administrative stuff.