Block Ciphers

Block Ciphers¶

• Block ciphers are algorithms that encrypt fixed length blocks.
  Using the encryption function E that takes plaintext blocks P as input and outputs ciphertext blocks C using a secret key k:
  
  \[ C = Een(k, P ) \]

This is called Symmetric-key Encryption or secret-key encryption. As the same key is used for encryption and decryption.

• Each Block will be mapped to another block.
• Taking this many time you get a encryption permutation rings.
• Different Keys will have a different permutation rings