PPT-Cryptography Lecture 13 Hash functions

Hash functions Cryptographic hash function deterministic function mapping arbitrary length inputs to a short fixedlength output sometimes called a digest Hash functions can be keyed or . 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 006 Fall 2009 Lecture 5 Hashing I Chaining Hash Functions Lecture Overview Dictionaries Motivation fast DNA comparison Hash functions Collisions Chaining Simple uniform hashing Good hash functions Readings CLRS Chapter 11 1 11 2 11 3 Dictionary Prob Exploiting the Entropy. in a Data Stream. Michael Mitzenmacher. Salil Vadhan. How Collaborations Arise…. At a talk on Bloom filters – a hash-based data structure.. Salil: Your analysis assumes perfectly random hash functions. What do you use in your experiments?. Cryptographic Tools (. cont. ). modified from slides of . Lawrie. Brown. Message Authentication. protects against active attacks. verifies received message is authentic. can use conventional encryption. Aalto . University. , . autumn. . 2012. Outline. Symmetric encryption. Public-key encryption. Cryptographic authentication. 2. Most. . important. !. Brief. . introduction. to . encryption. and . Dominique Unruh. University of Tartu. Surprises with hash functions. Consider a hash function and a horse race. “Spicy Spirit” wins…. Commitments and hashes. Player. Bookie.  . Player. Bookie. Slides by . Prem. Uppuluri. Some of the slides contain material from sources that are cited in those specific slides.. So far…. We looked at:. Symmetric or secret-key cryptography. Primarily used for encryption/decryption.. to’s. . u. sing . OpenSSL. In this session, we will cover cryptography basics and explore cryptographic functions, performance and examples using . OpenSSL. . . July 2012. LAB: . http://processors.wiki.ti.com/index.php/Sitara_Linux_Training:_Cryptography. Cryptography Lecture 14 Hash functions Q and A; b ring the written answers to TA before the class 1. Write down and remember the syntax and security definition Cryptography Lecture 13 Hash functions Hash functions (Cryptographic) hash function: deterministic function mapping arbitrary length inputs to a short, fixed-length output Hash functions can be keyed 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’ . . Patra. Quick Recall and Today’s Roadmap. >> Hash Function: Various Security Notions. >> . Markle-Damgaard. Domain . Extension. >> . Davis Meyer . Hash . function. >> Domain Extension for MAC using Hash function: Hash-and-Mac. hash functions. Hash functions are ubiquitous. Collision-resistance .  “fingerprinting”. Outsourced storage. Used as a “random oracle. ”. Used as a one-way function. Password hashing. Key .