diff options
Diffstat (limited to 'lib/aes.c')
| -rw-r--r-- | lib/aes.c | 52 |
1 files changed, 52 insertions, 0 deletions
@@ -580,3 +580,55 @@ void aes_decrypt(u8 *in, u8 *expkey, u8 *out) memcpy(out, state, sizeof(state)); } + +static void debug_print_vector(char *name, u32 num_bytes, u8 *data) +{ +#ifdef DEBUG + printf("%s [%d] @0x%08x", name, num_bytes, (u32)data); + print_buffer(0, data, 1, num_bytes, 16); +#endif +} + +/** + * Apply chain data to the destination using EOR + * + * Each array is of length AES_KEY_LENGTH. + * + * @cbc_chain_data Chain data + * @src Source data + * @dst Destination data, which is modified here + */ +static void apply_cbc_chain_data(u8 *cbc_chain_data, u8 *src, u8 *dst) +{ + int i; + + for (i = 0; i < AES_KEY_LENGTH; i++) + *dst++ = *src++ ^ *cbc_chain_data++; +} + +void aes_cbc_encrypt_blocks(u8 *key_exp, u8 *src, u8 *dst, u32 num_aes_blocks) +{ + u8 zero_key[AES_KEY_LENGTH] = { 0 }; + u8 tmp_data[AES_KEY_LENGTH]; + /* Convenient array of 0's for IV */ + u8 *cbc_chain_data = zero_key; + u32 i; + + for (i = 0; i < num_aes_blocks; i++) { + debug("encrypt_object: block %d of %d\n", i, num_aes_blocks); + debug_print_vector("AES Src", AES_KEY_LENGTH, src); + + /* Apply the chain data */ + apply_cbc_chain_data(cbc_chain_data, src, tmp_data); + debug_print_vector("AES Xor", AES_KEY_LENGTH, tmp_data); + + /* Encrypt the AES block */ + aes_encrypt(tmp_data, key_exp, dst); + debug_print_vector("AES Dst", AES_KEY_LENGTH, dst); + + /* Update pointers for next loop. */ + cbc_chain_data = dst; + src += AES_KEY_LENGTH; + dst += AES_KEY_LENGTH; + } +} |