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#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include "cipher.h"
#include "lilliput-ae.h"
static void _lilliput_tbc(const uint8_t key[KEY_BYTES],
const uint8_t tweak[TWEAK_BYTES],
const uint8_t message[BLOCK_BYTES],
uint8_t ciphertext[BLOCK_BYTES])
{
lilliput_tbc_encrypt(key, tweak, message, ciphertext, NULL);
}
static void _xor_into(size_t len, uint8_t dest[len], uint8_t src[len])
{
for (size_t i=0; i<len; i++)
dest[i] ^= src[i];
}
static void _process_associated_data(
const uint8_t key[KEY_BYTES],
size_t auth_data_len, const uint8_t auth_data[auth_data_len],
uint8_t auth[BLOCK_BYTES]
)
{
size_t l_a = auth_data_len / BLOCK_BYTES;
memset(auth, 0, BLOCK_BYTES);
for (size_t i=0; i<l_a; i++)
{
uint8_t tweak[TWEAK_BYTES];
/* TODO: generate tweak */
uint8_t Ek_Ai[BLOCK_BYTES];
_lilliput_tbc(key, tweak, auth_data+i*BLOCK_BYTES, Ek_Ai);
_xor_into(BLOCK_BYTES, auth, Ek_Ai);
}
}
static void _encrypt_message(
const uint8_t key[KEY_BYTES],
size_t message_len, const uint8_t message[message_len],
const uint8_t nonce[NONCE_BYTES],
size_t *ciphertext_len, uint8_t ciphertext[message_len+BLOCK_BYTES],
uint8_t final[BLOCK_BYTES]
)
{
}
static void _decrypt_message(
const uint8_t key[KEY_BYTES],
size_t ciphertext_len, const uint8_t ciphertext[ciphertext_len],
const uint8_t nonce[NONCE_BYTES],
size_t *message_len, uint8_t message[ciphertext_len],
uint8_t final[BLOCK_BYTES]
)
{
}
static void _generate_tag(
const uint8_t final[BLOCK_BYTES],
const uint8_t auth[BLOCK_BYTES],
uint8_t tag[TAG_BYTES]
)
{
}
void lilliput_ae_encrypt(
size_t message_len, const uint8_t message[message_len],
size_t auth_data_len, const uint8_t auth_data[auth_data_len],
const uint8_t key[KEY_BYTES],
const uint8_t nonce[NONCE_BYTES],
size_t *ciphertext_len, uint8_t ciphertext[message_len+BLOCK_BYTES],
uint8_t tag[TAG_BYTES]
)
{
uint8_t auth[BLOCK_BYTES];
_process_associated_data(key, auth_data_len, auth_data, auth);
uint8_t final[BLOCK_BYTES];
_encrypt_message(key, message_len, message, nonce,
ciphertext_len, ciphertext, final);
_generate_tag(final, auth, tag);
}
bool lilliput_ae_decrypt(
size_t ciphertext_len, const uint8_t ciphertext[ciphertext_len],
size_t auth_data_len, const uint8_t auth_data[auth_data_len],
const uint8_t key[KEY_BYTES],
const uint8_t nonce[NONCE_BYTES],
const uint8_t tag[TAG_BYTES],
size_t *message_len, uint8_t message[ciphertext_len]
)
{
uint8_t auth[BLOCK_BYTES];
_process_associated_data(key, auth_data_len, auth_data, auth);
uint8_t final[BLOCK_BYTES];
_decrypt_message(key, ciphertext_len, ciphertext, nonce,
message_len, message, final);
uint8_t effective_tag[TAG_BYTES];
_generate_tag(final, auth, effective_tag);
return memcmp(tag, effective_tag, TAG_BYTES) == 0;
}
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