Week 6 Lecture Notes

# Week 6 Lecture Notes - on a key to use RSA is Asymmetric...

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February 11: Lecture 16 Announcements Assignment 3 due by midnight (2/12) Midterm this Friday: Multiple Choice 20-25 questions, no history facts; general concept questions Answers to Assignments 1, 2, and 3 will be posted on WebtCT so go online to check the correct answers to each question. Chara. Freq. Fixed Length Code Total a 82 000 (82 x 3) => 246 bit b 15 001 45 bits c 28 010 84 bits d 43 011 129 bits e 127 100 381 bits f 22 101 66 bits g 20 110 60 bits 1011 bits Make shorter with an unambiguous “free-length” code. “Huffman” Coding fulfills this shorter code and gets the job done. In Huffman coding, common letters get shorter length while rare letters get longer length.

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February 13: Lecture 17 Is the Diffie-Hellman method an example of an Asymmetric Cipher? A : NO , it is symmetric because Alice and Bob AGREE
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Unformatted text preview: on a key to use RSA is Asymmetric Unbreakable Midterm Topics • What is Steganography? • What is Cryptography? • Transposition Ciphers – Example: Rail Shift Ciphers • Substitution Ciphers: Making and Breaking Them – Monoalphabetic – Caesar Shift – Codes, Nomenclators – Monoalphabetic with Codeword – Monoalphabetic with Homophones – Polyalphabetic: The Vigenere Cipher – One-time Pad Ciphers – Book Ciphers • Binary representations (e.g., ASCII) – An example binary transposition cipher – An example binary substitution cipher • Public-Key Cryptography – The Key Distribution Problem / Padlock Metaphor – One-way Functions – Modular Arithmetic – The Diffie-Hellman Protocol – Asymmetric Ciphers (vs. Symmetric) – RSA...
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## This note was uploaded on 04/03/2008 for the course LIGN 17 taught by Professor Kehler during the Winter '08 term at UCSD.

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Week 6 Lecture Notes - on a key to use RSA is Asymmetric...

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