# 6th Sense Technology

Topics: Cryptography, Encryption, RSA Pages: 4 (951 words) Published: February 20, 2013
Cryptography History
* Dates Back to Julius Ceaser
* Didn’t trust messanger
* Used “Shift by 3” method
Cryptography Basics
* Cryptosystem (Cipher System) – method of disguising messages so that only certain people can read them * Cryptography – Art of creating and using Cryptosystems * Cryptanalysis – Art of breaking Cryptosystems

* Cryptography – study of Cryptography and Cryptosystems * Symmetric Cryptosystems use the same key to encrypt and decrypt * You need to send the key securely
* Asymmetric Cryptosystems use a public key to encrypt and a private key to decrypt RSA Encryption
* Invented in 1978 by Ron Rivest, Adi Shamir and Leonard Adleman * Algorithm for public key encryption
RSA Encryption Algorithm
* 1. Find P and Q two large prime numbers
* 2. Choose E such that: 1<E<PQ
* E does not have to be prime, but must be odd
* (P-1)(Q-1) and E must not have no prime factors in common * 3. Compute D such that (DE-1) is evenly divisible by (P-1)(Q-1) * 4. Encryption function is C = (T^E) mod PQ
* C is the ciphertext (positive integer)
* T is the plaintext (positive integer)
* T must be less then the modulus PQ
* 5. Decryption function is T = (C^D) mod PQ
* C is the ciphertext (positive integer)
* T is the plaintext (positive integer)
* D is the private key

RSA Encryption
* Relying on
* No one can solve
* Would take to long to solve
* Theoretically Can be Broken
Quantum Cryptography History
* Early 1970’s Stephen Wiesner wrote “Conjugate Coding” * 1979 Charles H. Bennett and Gilles Brassard wrote various papers on the subject * Basis: Takes advantage of Heisenberg’s principle in which measuring a quantum system disturbs it and yields incomplete information Quantum Cryptography Setup

* Most widely used is the BB84 Protocol developed by IBM
* The sending apparatus consists of a...