Public-Key Cryptography Standards Number 7

cryptography

Definition

Public-Key Cryptography Standards Number 7

Public-Key Cryptography Standards Number 7 (PKCS#7) is a standard padding algorithm for block ciphers.

Operation

• If $N$ bytes are missing in the last block, add $N$ bytes with value $N$
• If the last block is full, add a new block where all bytes match the block size

Block size 10

HELLO! becomes HELLO!4444

FULLBLOCK becomes FULLBLOCK followed by a full block 10101010101010101010