December 6, 2017

Block Cipher - Encrypt More Than 1 Block

If you are going to encrypt (cipher) more than one block, you need a mode of operation for that.

For example the preferred cipher AES (Advanced Encryption Standard) uses

Key sizes  128, 192 or 256 bits
Block sizes  128 bits

Electronic CodeBook, ECB

Cipher Block Chaining, CBC with random IVs

Counter, CTR with unique nonces (Number only used ONCE)

Counter with CBC-MAC, CCM

Galois/Counter Mode, GCM

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