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Symmetric Key Cryptography (SKC) Nisha Mittal

Secret Key Cryptography (SKC) Symmetric Key Cryptography (SKC) Two basic types of secret-key cryptosystems substitution based cryptosystems transposition based cryptosystems

Substitution Technique A substitution technique is one in which the letters of plaintext are replaced by other letters or by numbers or symbols.

Substitution techniques Caesar Cipher Monoalphabetic Ciphers Playfair Cipher Hill Cipher Polyalphabetic Ciphers One-Time Pad

Caesar Cipher V Caesar Substitution cipher was by Julius Caesar. VThe Caesar cipher involves replacing each letter of the alphabet with the letter standing three places further down the alphabet.

Caesar Cipher substitution cipher was by Julius Caesar. The Caesar cipher involves replacing each letter of the alphabet with the letter standing three places further down the alphabert. For example, plain: MEET ME AFTER THE TOGA PARTY cipher: PHHW PH DIWHUWKH WRJD SDUWB

Caesar Cipher vsubstitution cipher was by Julius Caesar. V The Caesar cipher involves replacing each letter of the alphabet with the letter standing three places further down the alphabet For example, plain: meet me after the toga party cipher: PHHW PH DIWHUWKH WRJD SDUWB Note that the alphabet is wrapped around, so that the letter following Z is A.We can define the transformation by listing all possibilities, as follows: plain: abcdefghij k I m n o p cipher: d ef ghij kim n o p q rs