History

Caesar Cipher

Rotation Cipher

Two rows of letters in alphabetical order, second row is shifted

Enigma Cipher

Germans developed a cipher and a machine to encrypt & decrypt messages

Lots of energy was spent trying to decrypt the messages

Alan Turing, famous mathematician & computer scientist was involved in breaking

Digital Encryption Standard

National Institutes of Standards & Technology had a roposal for a Digital Encryption Standard

In 1977 IBM won the proposal with an algorithm on the Lucifer Cipher

3 DES

56 bit key for DES was inadequate

To get time a new one, 3DES was developed

Uses 3 keys

First Key used to encrypt plaintext

Second key used to decrypt the ciphertext from first round

Third key used to encrypt the cipher text from the second text

Advanced Encryption Standard

Again, NIST requested proposals to replace the Digital Encryption Standards

In 2001, NIST selected an algo called Rijndael to become the Advanced Encryption Standard

Supports multiple key lengths