The AES algorithm is a commonly used symmetric-key encryption algorithm, meaning that the same key is used for both encrypting and decrypting the data. The input and output data blocks for the AES algorithm are 16-bytes blocks (128-bits). AES has three key length types: 128-bit, 192-bit, and 256-bit. Before the AES encryption and encryption operation, an operation called key-expansion must be run when a key is given. The AES algorithm includes lots of bit-wise and byte-wise operations, so it is very suitable to be implemented with the hardware accelerator.
encryption/decryption
In applications, AES has five widely used usage models:
Electronic codebook (ECB)
Cipher block chaining (CBC)
Cipher feedback (CFB)
Output feedback (OFB)
Counter (CTR)
In this tutorial, you only involve ECB and CBC. The following figures provide explanations for these models.
NOTE: Figures are from Wikipedia.