Advanced Encryption System Accelerator v1

AES 128-bit Encryptor with SPI interface

AES 128-bit Encryptor with SPI interface

The Advanced Encryption Standard (AES) is a symmetric block cipher chosen by the U.S. government to protect classified information.

AES is implemented in software and hardware throughout the world to encrypt sensitive data.

How AES encryption works AES includes three block ciphers: AES-128 uses a 128-bit key length to encrypt and decrypt a block of messages. AES-192 uses a 192-bit key length to encrypt and decrypt a block of messages. AES-256 uses a 256-bit key length to encrypt and decrypt a block of messages. Each cipher encrypts and decrypts data in blocks of 128 bits using cryptographic keys of 128, 192 and 256 bits, respectively. Symmetric, also known as secret key, ciphers use the same key for encrypting and decrypting. The sender and the receiver must both know -- and use -- the same secret key. The government classifies information in three categories: Confidential, Secret or Top Secret. All key lengths can be used to protect the Confidential and Secret level. Top Secret information requires either 192- or 256-bit key lengths. There are 10 rounds for 128-bit keys, 12 rounds for 192-bit keys and 14 rounds for 256-bit keys. A round consists of several processing steps that include substitution, transposition and mixing of the input plaintext to transform it into the final output of ciphertext.