# ECE Technical Seminar Topic on Classical Cryptography PPT

## Introduction to Technical Seminar Topic on Classical Cryptography:

Cryptography is nothing but which is associated to the cryptology and crypt analysis, it includes the technique such as small dot, grouping words with images and other ways to envelop the order in storage space or transits. The fundamental concepts of this project are simple text, code text, encoding, decoding, crypt study, code etc.

In ciphers there are two types i.e., substitute and transposition. Again in substitution there are Mono-alphabetic, poly-alphabetic and poly-graphic. In transposition there are Skytel, Reverse, Rail Fence, Geometric and Row/Column. In the Mono-alphabetic substitution Caesar code is introduce,  first it is used in the military affairs .In this text replace each character by 3rd character and in the general mono-alphabetic substitute just shifting the alphabetic could shuffle the letters accidentally and each plain text letter maps to a dissimilar random code text.

In poly-alphabetic substitution code the vigenere code text is introduced basically the vignere is credited as the inventor of the “poly-alphabetic substitution code” to improve the security many mono-alphabetic substitution alphabets are used hence each character can be replaced by many others. In this code we use a key to select which alphabet is used for each letter of the communication and ith letter  of key specify ith alphabet to utilize and repeat from begin later than ending of key is reach.

Hill code also used in the mono-alphabetic substitution in this a multiple-letter encryption process is used to encrypts letters of plain text at each step and the encryption key is a m by n matrix of co-efficient.

In transposition codes a Skytel code used to strip the paper was wound round a staff and message written a long staff in rows, then paper removed leaving a strip of seemingly in random letters. The conclusion is some challenging area of crypt analysis, being the further side of improvement exercise will gain importance in view of the excess applications demanding assured security.