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pqc/crypto_sign/dilithium2aes/clean/sign.c
John M. Schanck 52750b86b1 Pull Dilithium changes from upstream
2021-02-09 10:43:16 -05:00

344 lines
12 KiB
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#include "fips202.h"
#include "packing.h"
#include "params.h"
#include "poly.h"
#include "polyvec.h"
#include "randombytes.h"
#include "sign.h"
#include "symmetric.h"
#include <stdint.h>
/*************************************************
* Name: PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_keypair
*
* Description: Generates public and private key.
*
* Arguments: - uint8_t *pk: pointer to output public key (allocated
* array of PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_PUBLICKEYBYTES bytes)
* - uint8_t *sk: pointer to output private key (allocated
* array of PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_SECRETKEYBYTES bytes)
*
* Returns 0 (success)
**************************************************/
int PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_keypair(uint8_t *pk, uint8_t *sk) {
uint8_t seedbuf[2 * SEEDBYTES + CRHBYTES];
uint8_t tr[SEEDBYTES];
const uint8_t *rho, *rhoprime, *key;
polyvecl mat[K];
polyvecl s1, s1hat;
polyveck s2, t1, t0;
/* Get randomness for rho, rhoprime and key */
randombytes(seedbuf, SEEDBYTES);
shake256(seedbuf, 2 * SEEDBYTES + CRHBYTES, seedbuf, SEEDBYTES);
rho = seedbuf;
rhoprime = rho + SEEDBYTES;
key = rhoprime + CRHBYTES;
/* Expand matrix */
PQCLEAN_DILITHIUM2AES_CLEAN_polyvec_matrix_expand(mat, rho);
/* Sample short vectors s1 and s2 */
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_uniform_eta(&s1, rhoprime, 0);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_uniform_eta(&s2, rhoprime, L);
/* Matrix-vector multiplication */
s1hat = s1;
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_ntt(&s1hat);
PQCLEAN_DILITHIUM2AES_CLEAN_polyvec_matrix_pointwise_montgomery(&t1, mat, &s1hat);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_reduce(&t1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_invntt_tomont(&t1);
/* Add error vector s2 */
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_add(&t1, &t1, &s2);
/* Extract t1 and write public key */
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_caddq(&t1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_power2round(&t1, &t0, &t1);
PQCLEAN_DILITHIUM2AES_CLEAN_pack_pk(pk, rho, &t1);
/* Compute H(rho, t1) and write secret key */
shake256(tr, SEEDBYTES, pk, PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_PUBLICKEYBYTES);
PQCLEAN_DILITHIUM2AES_CLEAN_pack_sk(sk, rho, tr, key, &t0, &s1, &s2);
return 0;
}
/*************************************************
* Name: PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_signature
*
* Description: Computes signature.
*
* Arguments: - uint8_t *sig: pointer to output signature (of length PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES)
* - size_t *siglen: pointer to output length of signature
* - uint8_t *m: pointer to message to be signed
* - size_t mlen: length of message
* - uint8_t *sk: pointer to bit-packed secret key
*
* Returns 0 (success)
**************************************************/
int PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_signature(uint8_t *sig,
size_t *siglen,
const uint8_t *m,
size_t mlen,
const uint8_t *sk) {
unsigned int n;
uint8_t seedbuf[3 * SEEDBYTES + 2 * CRHBYTES];
uint8_t *rho, *tr, *key, *mu, *rhoprime;
uint16_t nonce = 0;
polyvecl mat[K], s1, y, z;
polyveck t0, s2, w1, w0, h;
poly cp;
shake256incctx state;
rho = seedbuf;
tr = rho + SEEDBYTES;
key = tr + SEEDBYTES;
mu = key + SEEDBYTES;
rhoprime = mu + CRHBYTES;
PQCLEAN_DILITHIUM2AES_CLEAN_unpack_sk(rho, tr, key, &t0, &s1, &s2, sk);
/* Compute CRH(tr, msg) */
shake256_inc_init(&state);
shake256_inc_absorb(&state, tr, SEEDBYTES);
shake256_inc_absorb(&state, m, mlen);
shake256_inc_finalize(&state);
shake256_inc_squeeze(mu, CRHBYTES, &state);
shake256_inc_ctx_release(&state);
shake256(rhoprime, CRHBYTES, key, SEEDBYTES + CRHBYTES);
/* Expand matrix and transform vectors */
PQCLEAN_DILITHIUM2AES_CLEAN_polyvec_matrix_expand(mat, rho);
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_ntt(&s1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_ntt(&s2);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_ntt(&t0);
rej:
/* Sample intermediate vector y */
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_uniform_gamma1(&y, rhoprime, nonce++);
/* Matrix-vector multiplication */
z = y;
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_ntt(&z);
PQCLEAN_DILITHIUM2AES_CLEAN_polyvec_matrix_pointwise_montgomery(&w1, mat, &z);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_reduce(&w1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_invntt_tomont(&w1);
/* Decompose w and call the random oracle */
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_caddq(&w1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_decompose(&w1, &w0, &w1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_pack_w1(sig, &w1);
shake256_inc_init(&state);
shake256_inc_absorb(&state, mu, CRHBYTES);
shake256_inc_absorb(&state, sig, K * POLYW1_PACKEDBYTES);
shake256_inc_finalize(&state);
shake256_inc_squeeze(sig, SEEDBYTES, &state);
shake256_inc_ctx_release(&state);
PQCLEAN_DILITHIUM2AES_CLEAN_poly_challenge(&cp, sig);
PQCLEAN_DILITHIUM2AES_CLEAN_poly_ntt(&cp);
/* Compute z, reject if it reveals secret */
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_pointwise_poly_montgomery(&z, &cp, &s1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_invntt_tomont(&z);
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_add(&z, &z, &y);
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_reduce(&z);
if (PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_chknorm(&z, GAMMA1 - BETA)) {
goto rej;
}
/* Check that subtracting cs2 does not change high bits of w and low bits
* do not reveal secret information */
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_pointwise_poly_montgomery(&h, &cp, &s2);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_invntt_tomont(&h);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_sub(&w0, &w0, &h);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_reduce(&w0);
if (PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_chknorm(&w0, GAMMA2 - BETA)) {
goto rej;
}
/* Compute hints for w1 */
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_pointwise_poly_montgomery(&h, &cp, &t0);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_invntt_tomont(&h);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_reduce(&h);
if (PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_chknorm(&h, GAMMA2)) {
goto rej;
}
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_add(&w0, &w0, &h);
n = PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_make_hint(&h, &w0, &w1);
if (n > OMEGA) {
goto rej;
}
/* Write signature */
PQCLEAN_DILITHIUM2AES_CLEAN_pack_sig(sig, sig, &z, &h);
*siglen = PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES;
return 0;
}
/*************************************************
* Name: PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign
*
* Description: Compute signed message.
*
* Arguments: - uint8_t *sm: pointer to output signed message (allocated
* array with PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES + mlen bytes),
* can be equal to m
* - size_t *smlen: pointer to output length of signed
* message
* - const uint8_t *m: pointer to message to be signed
* - size_t mlen: length of message
* - const uint8_t *sk: pointer to bit-packed secret key
*
* Returns 0 (success)
**************************************************/
int PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign(uint8_t *sm,
size_t *smlen,
const uint8_t *m,
size_t mlen,
const uint8_t *sk) {
size_t i;
for (i = 0; i < mlen; ++i) {
sm[PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES + mlen - 1 - i] = m[mlen - 1 - i];
}
PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_signature(sm, smlen, sm + PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES, mlen, sk);
*smlen += mlen;
return 0;
}
/*************************************************
* Name: PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_verify
*
* Description: Verifies signature.
*
* Arguments: - uint8_t *m: pointer to input signature
* - size_t siglen: length of signature
* - const uint8_t *m: pointer to message
* - size_t mlen: length of message
* - const uint8_t *pk: pointer to bit-packed public key
*
* Returns 0 if signature could be verified correctly and -1 otherwise
**************************************************/
int PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_verify(const uint8_t *sig,
size_t siglen,
const uint8_t *m,
size_t mlen,
const uint8_t *pk) {
unsigned int i;
uint8_t buf[K * POLYW1_PACKEDBYTES];
uint8_t rho[SEEDBYTES];
uint8_t mu[CRHBYTES];
uint8_t c[SEEDBYTES];
uint8_t c2[SEEDBYTES];
poly cp;
polyvecl mat[K], z;
polyveck t1, w1, h;
shake256incctx state;
if (siglen != PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES) {
return -1;
}
PQCLEAN_DILITHIUM2AES_CLEAN_unpack_pk(rho, &t1, pk);
if (PQCLEAN_DILITHIUM2AES_CLEAN_unpack_sig(c, &z, &h, sig)) {
return -1;
}
if (PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_chknorm(&z, GAMMA1 - BETA)) {
return -1;
}
/* Compute CRH(H(rho, t1), msg) */
shake256(mu, SEEDBYTES, pk, PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_PUBLICKEYBYTES);
shake256_inc_init(&state);
shake256_inc_absorb(&state, mu, SEEDBYTES);
shake256_inc_absorb(&state, m, mlen);
shake256_inc_finalize(&state);
shake256_inc_squeeze(mu, CRHBYTES, &state);
shake256_inc_ctx_release(&state);
/* Matrix-vector multiplication; compute Az - c2^dt1 */
PQCLEAN_DILITHIUM2AES_CLEAN_poly_challenge(&cp, c);
PQCLEAN_DILITHIUM2AES_CLEAN_polyvec_matrix_expand(mat, rho);
PQCLEAN_DILITHIUM2AES_CLEAN_polyvecl_ntt(&z);
PQCLEAN_DILITHIUM2AES_CLEAN_polyvec_matrix_pointwise_montgomery(&w1, mat, &z);
PQCLEAN_DILITHIUM2AES_CLEAN_poly_ntt(&cp);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_shiftl(&t1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_ntt(&t1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_pointwise_poly_montgomery(&t1, &cp, &t1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_sub(&w1, &w1, &t1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_reduce(&w1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_invntt_tomont(&w1);
/* Reconstruct w1 */
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_caddq(&w1);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_use_hint(&w1, &w1, &h);
PQCLEAN_DILITHIUM2AES_CLEAN_polyveck_pack_w1(buf, &w1);
/* Call random oracle and verify PQCLEAN_DILITHIUM2AES_CLEAN_challenge */
shake256_inc_init(&state);
shake256_inc_absorb(&state, mu, CRHBYTES);
shake256_inc_absorb(&state, buf, K * POLYW1_PACKEDBYTES);
shake256_inc_finalize(&state);
shake256_inc_squeeze(c2, SEEDBYTES, &state);
shake256_inc_ctx_release(&state);
for (i = 0; i < SEEDBYTES; ++i) {
if (c[i] != c2[i]) {
return -1;
}
}
return 0;
}
/*************************************************
* Name: PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_open
*
* Description: Verify signed message.
*
* Arguments: - uint8_t *m: pointer to output message (allocated
* array with smlen bytes), can be equal to sm
* - size_t *mlen: pointer to output length of message
* - const uint8_t *sm: pointer to signed message
* - size_t smlen: length of signed message
* - const uint8_t *pk: pointer to bit-packed public key
*
* Returns 0 if signed message could be verified correctly and -1 otherwise
**************************************************/
int PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_open(uint8_t *m,
size_t *mlen,
const uint8_t *sm,
size_t smlen,
const uint8_t *pk) {
size_t i;
if (smlen < PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES) {
goto badsig;
}
*mlen = smlen - PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES;
if (PQCLEAN_DILITHIUM2AES_CLEAN_crypto_sign_verify(sm, PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES, sm + PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES, *mlen, pk)) {
goto badsig;
} else {
/* All good, copy msg, return 0 */
for (i = 0; i < *mlen; ++i) {
m[i] = sm[PQCLEAN_DILITHIUM2AES_CLEAN_CRYPTO_BYTES + i];
}
return 0;
}
badsig:
/* Signature verification failed */
*mlen = (size_t) -1;
for (i = 0; i < smlen; ++i) {
m[i] = 0;
}
return -1;
}
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