Link to this headingBlock 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