Source (https://github.com/torvalds/linux/blob/master/include/crypto/aes.h)
#define AES_MIN_KEY_SIZE 16
#define AES_MAX_KEY_SIZE 32
#define AES_KEYSIZE_128 16
#define AES_KEYSIZE_192 24
#define AES_KEYSIZE_256 32
#define AES_BLOCK_SIZE 16
#define AES_MAX_KEYLENGTH (15 * 16)
#define AES_MAX_KEYLENGTH_U32 (AES_MAX_KEYLENGTH / sizeof(u32))
Before we begin, the formula for converting bytes to bits is to multiply by eight.
Example: 4 bytes to bits. 4 * 8 = 32 bits.
#define AES_MIN_KEY_SIZE 16
Because the minimum key size is 16-bytes that's a 128-bit key. So minimum would = AES-128.
#define AES_MAX_KEY_SIZE 32
Because the maximum key size is 32-bytes that's a 256-bit key. So maximum would = AES-256.
#define AES_BLOCK_SIZE 16
The block size is 128 bits.