Module aes_frast::aes_core

The aes_core mod provides the essential functions of AES, including key scheduling and single-block crypto.

aes_core

aes_core is the core part of AES crypto, including key scheduling, block encryption and decryption.

This module provides low-level API.

In this library, AES is implemented by looking-up-tables.

Attention!

This low-level API does NOT provide error handling.

Please be careful with the lengths of the slices when passing it as the parameters of a function. Otherwise, it will panic at index out of bounds or assertion failed.

Block cipher

The AES algorithm only supports 128-bit (16 bytes) block.

It supports 128-bit (16 bytes), 192-bit (24 bytes) and 265-bit (32 bytes) keys.

AES block crypto uses sub-keys (aka working keys), which are derived from a key. This derivation process is called key schedule or key expansion.

key size in bits	key size in bytes	sub-keys size in 32-bit words
128	16	44
192	24	52
256	32	60

Constants

• BLOCKSIZE_IN_BYTES
  AES block size in bytes, which is 16.
• KEY_BYTES_128BIT
  128bit key size in bytes, which is 16.
• KEY_BYTES_192BIT
  192bit key size in bytes, which is 24.
• KEY_BYTES_256BIT
  256bit key size in bytes, which is 32.
• N_SUBKEYS_128BIT
  Sub-keys size in words (u32) from 128bit key, which is 44.
• N_SUBKEYS_192BIT
  Sub-keys size in words (u32) from 192bit key, which is 52.
• N_SUBKEYS_256BIT
  Sub-keys size in words (u32) from 256bit key, which is 60.

Functions

• block_decrypt128
  Decrypt a block with scheduled keys (from 128bit key).
• block_decrypt128_inplace
  Decrypt a block with scheduled keys (from 128bit key) in place.
• block_decrypt192
  Decrypt a block with scheduled keys (from 192bit key).
• block_decrypt192_inplace
  Decrypt a block with scheduled keys (from 192bit key) in place.
• block_decrypt256
  Decrypt a block with scheduled keys (from 256bit key).
• block_decrypt256_inplace
  Decrypt a block with scheduled keys (from 256bit key) in place.
• block_encrypt128
  Encrypt a block with scheduled keys (from 128bit key).
• block_encrypt128_inplace
  Encrypt a block with scheduled keys (from 128bit key) in place.
• block_encrypt192
  Encrypt a block with scheduled keys (from 192bit key).
• block_encrypt192_inplace
  Encrypt a block with scheduled keys (from 192bit key) in place.
• block_encrypt256
  Encrypt a block with scheduled keys (from 256bit key).
• block_encrypt256_inplace
  Encrypt a block with scheduled keys (from 256bit key) in place.
• key_schedule_decrypt128
  Schedule a 128bit key to sub-keys for decryption.
• key_schedule_decrypt192
  Schedule a 192bit key to sub-keys for decryption.
• key_schedule_decrypt256
  Schedule a 256bit key to sub-keys for decryption.
• key_schedule_decrypt_auto
  Schedule a key to sub-keys for decryption with auto-selected key-size.
• key_schedule_encrypt128
  Schedule a 128bit key to sub-keys for encryption.
• key_schedule_encrypt192
  Schedule a 192bit key to sub-keys for encryption.
• key_schedule_encrypt256
  Schedule a 256bit key to sub-keys for encryption.
• key_schedule_encrypt_auto
  Schedule a key to sub-keys for encryption with auto-selected key-size.