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#define RATE 16
static void
aegis256_init(const uint8_t *key, const uint8_t *nonce, aes_block_t *const state)
{
static CRYPTO_ALIGN(AES_BLOCK_LENGTH)
const uint8_t c0_[AES_BLOCK_LENGTH] = { 0x00, 0x01, 0x01, 0x02, 0x03, 0x05, 0x08, 0x0d,
0x15, 0x22, 0x37, 0x59, 0x90, 0xe9, 0x79, 0x62 };
static CRYPTO_ALIGN(AES_BLOCK_LENGTH)
const uint8_t c1_[AES_BLOCK_LENGTH] = { 0xdb, 0x3d, 0x18, 0x55, 0x6d, 0xc2, 0x2f, 0xf1,
0x20, 0x11, 0x31, 0x42, 0x73, 0xb5, 0x28, 0xdd };
const aes_block_t c0 = AES_BLOCK_LOAD(c0_);
const aes_block_t c1 = AES_BLOCK_LOAD(c1_);
const aes_block_t k0 = AES_BLOCK_LOAD(key);
const aes_block_t k1 = AES_BLOCK_LOAD(key + AES_BLOCK_LENGTH);
const aes_block_t n0 = AES_BLOCK_LOAD(nonce);
const aes_block_t n1 = AES_BLOCK_LOAD(nonce + AES_BLOCK_LENGTH);
const aes_block_t k0_n0 = AES_BLOCK_XOR(k0, n0);
const aes_block_t k1_n1 = AES_BLOCK_XOR(k1, n1);
int i;
state[0] = k0_n0;
state[1] = k1_n1;
state[2] = c1;
state[3] = c0;
state[4] = AES_BLOCK_XOR(k0, c0);
state[5] = AES_BLOCK_XOR(k1, c1);
for (i = 0; i < 4; i++) {
aegis256_update(state, k0);
aegis256_update(state, k1);
aegis256_update(state, k0_n0);
aegis256_update(state, k1_n1);
}
}
static int
aegis256_mac(uint8_t *mac, size_t maclen, size_t adlen, size_t mlen, aes_block_t *const state)
{
aes_block_t tmp;
int i;
tmp = AES_BLOCK_LOAD_64x2(((uint64_t) mlen) << 3, ((uint64_t) adlen) << 3);
tmp = AES_BLOCK_XOR(tmp, state[3]);
for (i = 0; i < 7; i++) {
aegis256_update(state, tmp);
}
if (maclen == 16) {
tmp = AES_BLOCK_XOR(state[5], state[4]);
tmp = AES_BLOCK_XOR(tmp, AES_BLOCK_XOR(state[3], state[2]));
tmp = AES_BLOCK_XOR(tmp, AES_BLOCK_XOR(state[1], state[0]));
AES_BLOCK_STORE(mac, tmp);
} else if (maclen == 32) {
tmp = AES_BLOCK_XOR(AES_BLOCK_XOR(state[2], state[1]), state[0]);
AES_BLOCK_STORE(mac, tmp);
tmp = AES_BLOCK_XOR(AES_BLOCK_XOR(state[5], state[4]), state[3]);
AES_BLOCK_STORE(mac + 16, tmp);
} else {
memset(mac, 0, maclen);
return -1;
}
return 0;
}
static inline void
aegis256_absorb(const uint8_t *const src, aes_block_t *const state)
{
aes_block_t msg;
msg = AES_BLOCK_LOAD(src);
aegis256_update(state, msg);
}
static inline void
aegis256_absorb2(const uint8_t *const src, aes_block_t *const state)
{
aes_block_t msg, msg2;
msg = AES_BLOCK_LOAD(src + 0 * AES_BLOCK_LENGTH);
msg2 = AES_BLOCK_LOAD(src + 1 * AES_BLOCK_LENGTH);
aegis256_update(state, msg);
aegis256_update(state, msg2);
}
static void
aegis256_enc(uint8_t *const dst, const uint8_t *const src, aes_block_t *const state)
{
aes_block_t msg;
aes_block_t tmp;
msg = AES_BLOCK_LOAD(src);
tmp = AES_BLOCK_XOR(msg, state[5]);
tmp = AES_BLOCK_XOR(tmp, state[4]);
tmp = AES_BLOCK_XOR(tmp, state[1]);
tmp = AES_BLOCK_XOR(tmp, AES_BLOCK_AND(state[2], state[3]));
AES_BLOCK_STORE(dst, tmp);
aegis256_update(state, msg);
}
static void
aegis256_dec(uint8_t *const dst, const uint8_t *const src, aes_block_t *const state)
{
aes_block_t msg;
msg = AES_BLOCK_LOAD(src);
msg = AES_BLOCK_XOR(msg, state[5]);
msg = AES_BLOCK_XOR(msg, state[4]);
msg = AES_BLOCK_XOR(msg, state[1]);
msg = AES_BLOCK_XOR(msg, AES_BLOCK_AND(state[2], state[3]));
AES_BLOCK_STORE(dst, msg);
aegis256_update(state, msg);
}
static void
aegis256_declast(uint8_t *const dst, const uint8_t *const src, size_t len, aes_block_t *const state)
{
uint8_t pad[RATE];
aes_block_t msg;
memset(pad, 0, sizeof pad);
memcpy(pad, src, len);
msg = AES_BLOCK_LOAD(pad);
msg = AES_BLOCK_XOR(msg, state[5]);
msg = AES_BLOCK_XOR(msg, state[4]);
msg = AES_BLOCK_XOR(msg, state[1]);
msg = AES_BLOCK_XOR(msg, AES_BLOCK_AND(state[2], state[3]));
AES_BLOCK_STORE(pad, msg);
memset(pad + len, 0, sizeof pad - len);
memcpy(dst, pad, len);
msg = AES_BLOCK_LOAD(pad);
aegis256_update(state, msg);
}
static int
encrypt_detached(uint8_t *c, uint8_t *mac, size_t maclen, const uint8_t *m, size_t mlen,
const uint8_t *ad, size_t adlen, const uint8_t *npub, const uint8_t *k)
{
aes_block_t state[6];
CRYPTO_ALIGN(RATE) uint8_t src[RATE];
CRYPTO_ALIGN(RATE) uint8_t dst[RATE];
size_t i;
aegis256_init(k, npub, state);
for (i = 0; i + 2 * RATE <= adlen; i += 2 * RATE) {
aegis256_absorb2(ad + i, state);
}
for (; i + RATE <= adlen; i += RATE) {
aegis256_absorb(ad + i, state);
}
if (adlen % RATE) {
memset(src, 0, RATE);
memcpy(src, ad + i, adlen % RATE);
aegis256_absorb(src, state);
}
for (i = 0; i + RATE <= mlen; i += RATE) {
aegis256_enc(c + i, m + i, state);
}
if (mlen % RATE) {
memset(src, 0, RATE);
memcpy(src, m + i, mlen % RATE);
aegis256_enc(dst, src, state);
memcpy(c + i, dst, mlen % RATE);
}
return aegis256_mac(mac, maclen, adlen, mlen, state);
}
static int
decrypt_detached(uint8_t *m, const uint8_t *c, size_t clen, const uint8_t *mac, size_t maclen,
const uint8_t *ad, size_t adlen, const uint8_t *npub, const uint8_t *k)
{
aes_block_t state[6];
CRYPTO_ALIGN(RATE) uint8_t src[RATE];
CRYPTO_ALIGN(RATE) uint8_t dst[RATE];
CRYPTO_ALIGN(16) uint8_t computed_mac[32];
const size_t mlen = clen;
size_t i;
int ret;
aegis256_init(k, npub, state);
for (i = 0; i + 2 * RATE <= adlen; i += 2 * RATE) {
aegis256_absorb2(ad + i, state);
}
for (; i + RATE <= adlen; i += RATE) {
aegis256_absorb(ad + i, state);
}
if (adlen % RATE) {
memset(src, 0, RATE);
memcpy(src, ad + i, adlen % RATE);
aegis256_absorb(src, state);
}
if (m != NULL) {
for (i = 0; i + RATE <= mlen; i += RATE) {
aegis256_dec(m + i, c + i, state);
}
} else {
for (i = 0; i + RATE <= mlen; i += RATE) {
aegis256_dec(dst, c + i, state);
}
}
if (mlen % RATE) {
if (m != NULL) {
aegis256_declast(m + i, c + i, mlen % RATE, state);
} else {
aegis256_declast(dst, c + i, mlen % RATE, state);
}
}
COMPILER_ASSERT(sizeof computed_mac >= 32);
ret = -1;
if (aegis256_mac(computed_mac, maclen, adlen, mlen, state) == 0) {
if (maclen == 16) {
ret = crypto_verify_16(computed_mac, mac);
} else if (maclen == 32) {
ret = crypto_verify_32(computed_mac, mac);
}
}
if (ret != 0 && m != NULL) {
memset(m, 0, mlen);
}
return ret;
}
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