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pqcrypto/crypto_kem/kyber512/avx2/indcpa.c
John M. Schanck 127e9ec326 Round 3 Kyber
2021-03-24 21:02:49 +00:00

353 lines
14 KiB
C

#include "align.h"
#include "cbd.h"
#include "indcpa.h"
#include "ntt.h"
#include "params.h"
#include "poly.h"
#include "polyvec.h"
#include "randombytes.h"
#include "rejsample.h"
#include "symmetric.h"
#include <immintrin.h>
#include <stddef.h>
#include <stdint.h>
/*************************************************
* Name: pack_pk
*
* Description: Serialize the public key as concatenation of the
* serialized vector of polynomials pk and the
* public seed used to generate the matrix A.
* The polynomial coefficients in pk are assumed to
* lie in the invertal [0,q], i.e. pk must be reduced
* by PQCLEAN_KYBER512_AVX2_polyvec_reduce().
*
* Arguments: uint8_t *r: pointer to the output serialized public key
* polyvec *pk: pointer to the input public-key polyvec
* const uint8_t *seed: pointer to the input public seed
**************************************************/
static void pack_pk(uint8_t r[KYBER_INDCPA_PUBLICKEYBYTES],
polyvec *pk,
const uint8_t seed[KYBER_SYMBYTES]) {
size_t i;
PQCLEAN_KYBER512_AVX2_polyvec_tobytes(r, pk);
for (i = 0; i < KYBER_SYMBYTES; i++) {
r[i + KYBER_POLYVECBYTES] = seed[i];
}
}
/*************************************************
* Name: unpack_pk
*
* Description: De-serialize public key from a byte array;
* approximate inverse of pack_pk
*
* Arguments: - polyvec *pk: pointer to output public-key polynomial vector
* - uint8_t *seed: pointer to output seed to generate matrix A
* - const uint8_t *packedpk: pointer to input serialized public key
**************************************************/
static void unpack_pk(polyvec *pk,
uint8_t seed[KYBER_SYMBYTES],
const uint8_t packedpk[KYBER_INDCPA_PUBLICKEYBYTES]) {
size_t i;
PQCLEAN_KYBER512_AVX2_polyvec_frombytes(pk, packedpk);
for (i = 0; i < KYBER_SYMBYTES; i++) {
seed[i] = packedpk[i + KYBER_POLYVECBYTES];
}
}
/*************************************************
* Name: pack_sk
*
* Description: Serialize the secret key.
* The polynomial coefficients in sk are assumed to
* lie in the invertal [0,q], i.e. sk must be reduced
* by PQCLEAN_KYBER512_AVX2_polyvec_reduce().
*
* Arguments: - uint8_t *r: pointer to output serialized secret key
* - polyvec *sk: pointer to input vector of polynomials (secret key)
**************************************************/
static void pack_sk(uint8_t r[KYBER_INDCPA_SECRETKEYBYTES], polyvec *sk) {
PQCLEAN_KYBER512_AVX2_polyvec_tobytes(r, sk);
}
/*************************************************
* Name: unpack_sk
*
* Description: De-serialize the secret key; inverse of pack_sk
*
* Arguments: - polyvec *sk: pointer to output vector of polynomials (secret key)
* - const uint8_t *packedsk: pointer to input serialized secret key
**************************************************/
static void unpack_sk(polyvec *sk, const uint8_t packedsk[KYBER_INDCPA_SECRETKEYBYTES]) {
PQCLEAN_KYBER512_AVX2_polyvec_frombytes(sk, packedsk);
}
/*************************************************
* Name: pack_ciphertext
*
* Description: Serialize the ciphertext as concatenation of the
* compressed and serialized vector of polynomials b
* and the compressed and serialized polynomial v.
* The polynomial coefficients in b and v are assumed to
* lie in the invertal [0,q], i.e. b and v must be reduced
* by PQCLEAN_KYBER512_AVX2_polyvec_reduce() and PQCLEAN_KYBER512_AVX2_poly_reduce(), respectively.
*
* Arguments: uint8_t *r: pointer to the output serialized ciphertext
* poly *pk: pointer to the input vector of polynomials b
* poly *v: pointer to the input polynomial v
**************************************************/
static void pack_ciphertext(uint8_t r[KYBER_INDCPA_BYTES], polyvec *b, poly *v) {
PQCLEAN_KYBER512_AVX2_polyvec_compress(r, b);
PQCLEAN_KYBER512_AVX2_poly_compress(r + KYBER_POLYVECCOMPRESSEDBYTES, v);
}
/*************************************************
* Name: unpack_ciphertext
*
* Description: De-serialize and decompress ciphertext from a byte array;
* approximate inverse of pack_ciphertext
*
* Arguments: - polyvec *b: pointer to the output vector of polynomials b
* - poly *v: pointer to the output polynomial v
* - const uint8_t *c: pointer to the input serialized ciphertext
**************************************************/
static void unpack_ciphertext(polyvec *b, poly *v, const uint8_t c[KYBER_INDCPA_BYTES]) {
PQCLEAN_KYBER512_AVX2_polyvec_decompress(b, c);
PQCLEAN_KYBER512_AVX2_poly_decompress(v, c + KYBER_POLYVECCOMPRESSEDBYTES);
}
/*************************************************
* Name: rej_uniform
*
* Description: Run rejection sampling on uniform random bytes to generate
* uniform random integers mod q
*
* Arguments: - int16_t *r: pointer to output array
* - unsigned int len: requested number of 16-bit integers (uniform mod q)
* - const uint8_t *buf: pointer to input buffer (assumed to be uniformly random bytes)
* - unsigned int buflen: length of input buffer in bytes
*
* Returns number of sampled 16-bit integers (at most len)
**************************************************/
static unsigned int rej_uniform(int16_t *r,
unsigned int len,
const uint8_t *buf,
unsigned int buflen) {
unsigned int ctr, pos;
uint16_t val0, val1;
ctr = pos = 0;
while (ctr < len && pos + 3 <= buflen) {
val0 = ((buf[pos + 0] >> 0) | ((uint16_t)buf[pos + 1] << 8)) & 0xFFF;
val1 = ((buf[pos + 1] >> 4) | ((uint16_t)buf[pos + 2] << 4)) & 0xFFF;
pos += 3;
if (val0 < KYBER_Q) {
r[ctr++] = val0;
}
if (ctr < len && val1 < KYBER_Q) {
r[ctr++] = val1;
}
}
return ctr;
}
#define gen_a(A,B) PQCLEAN_KYBER512_AVX2_gen_matrix(A,B,0)
#define gen_at(A,B) PQCLEAN_KYBER512_AVX2_gen_matrix(A,B,1)
/*************************************************
* Name: PQCLEAN_KYBER512_AVX2_gen_matrix
*
* Description: Deterministically generate matrix A (or the transpose of A)
* from a seed. Entries of the matrix are polynomials that look
* uniformly random. Performs rejection sampling on output of
* a XOF
*
* Arguments: - polyvec *a: pointer to ouptput matrix A
* - const uint8_t *seed: pointer to input seed
* - int transposed: boolean deciding whether A or A^T is generated
**************************************************/
void PQCLEAN_KYBER512_AVX2_gen_matrix(polyvec *a, const uint8_t seed[32], int transposed) {
unsigned int ctr0, ctr1, ctr2, ctr3;
ALIGNED_UINT8(REJ_UNIFORM_AVX_NBLOCKS * SHAKE128_RATE) buf[4];
__m256i f;
keccakx4_state state;
f = _mm256_loadu_si256((__m256i *)seed);
_mm256_store_si256(buf[0].vec, f);
_mm256_store_si256(buf[1].vec, f);
_mm256_store_si256(buf[2].vec, f);
_mm256_store_si256(buf[3].vec, f);
if (transposed) {
buf[0].coeffs[32] = 0;
buf[0].coeffs[33] = 0;
buf[1].coeffs[32] = 0;
buf[1].coeffs[33] = 1;
buf[2].coeffs[32] = 1;
buf[2].coeffs[33] = 0;
buf[3].coeffs[32] = 1;
buf[3].coeffs[33] = 1;
} else {
buf[0].coeffs[32] = 0;
buf[0].coeffs[33] = 0;
buf[1].coeffs[32] = 1;
buf[1].coeffs[33] = 0;
buf[2].coeffs[32] = 0;
buf[2].coeffs[33] = 1;
buf[3].coeffs[32] = 1;
buf[3].coeffs[33] = 1;
}
PQCLEAN_KYBER512_AVX2_shake128x4_absorb_once(&state, buf[0].coeffs, buf[1].coeffs, buf[2].coeffs, buf[3].coeffs, 34);
PQCLEAN_KYBER512_AVX2_shake128x4_squeezeblocks(buf[0].coeffs, buf[1].coeffs, buf[2].coeffs, buf[3].coeffs, REJ_UNIFORM_AVX_NBLOCKS, &state);
ctr0 = PQCLEAN_KYBER512_AVX2_rej_uniform_avx(a[0].vec[0].coeffs, buf[0].coeffs);
ctr1 = PQCLEAN_KYBER512_AVX2_rej_uniform_avx(a[0].vec[1].coeffs, buf[1].coeffs);
ctr2 = PQCLEAN_KYBER512_AVX2_rej_uniform_avx(a[1].vec[0].coeffs, buf[2].coeffs);
ctr3 = PQCLEAN_KYBER512_AVX2_rej_uniform_avx(a[1].vec[1].coeffs, buf[3].coeffs);
while (ctr0 < KYBER_N || ctr1 < KYBER_N || ctr2 < KYBER_N || ctr3 < KYBER_N) {
PQCLEAN_KYBER512_AVX2_shake128x4_squeezeblocks(buf[0].coeffs, buf[1].coeffs, buf[2].coeffs, buf[3].coeffs, 1, &state);
ctr0 += rej_uniform(a[0].vec[0].coeffs + ctr0, KYBER_N - ctr0, buf[0].coeffs, SHAKE128_RATE);
ctr1 += rej_uniform(a[0].vec[1].coeffs + ctr1, KYBER_N - ctr1, buf[1].coeffs, SHAKE128_RATE);
ctr2 += rej_uniform(a[1].vec[0].coeffs + ctr2, KYBER_N - ctr2, buf[2].coeffs, SHAKE128_RATE);
ctr3 += rej_uniform(a[1].vec[1].coeffs + ctr3, KYBER_N - ctr3, buf[3].coeffs, SHAKE128_RATE);
}
PQCLEAN_KYBER512_AVX2_poly_nttunpack(&a[0].vec[0]);
PQCLEAN_KYBER512_AVX2_poly_nttunpack(&a[0].vec[1]);
PQCLEAN_KYBER512_AVX2_poly_nttunpack(&a[1].vec[0]);
PQCLEAN_KYBER512_AVX2_poly_nttunpack(&a[1].vec[1]);
}
/*************************************************
* Name: PQCLEAN_KYBER512_AVX2_indcpa_keypair
*
* Description: Generates public and private key for the CPA-secure
* public-key encryption scheme underlying Kyber
*
* Arguments: - uint8_t *pk: pointer to output public key
* (of length KYBER_INDCPA_PUBLICKEYBYTES bytes)
* - uint8_t *sk: pointer to output private key
(of length KYBER_INDCPA_SECRETKEYBYTES bytes)
**************************************************/
void PQCLEAN_KYBER512_AVX2_indcpa_keypair(uint8_t pk[KYBER_INDCPA_PUBLICKEYBYTES],
uint8_t sk[KYBER_INDCPA_SECRETKEYBYTES]) {
unsigned int i;
uint8_t buf[2 * KYBER_SYMBYTES];
const uint8_t *publicseed = buf;
const uint8_t *noiseseed = buf + KYBER_SYMBYTES;
polyvec a[KYBER_K], e, pkpv, skpv;
randombytes(buf, KYBER_SYMBYTES);
hash_g(buf, buf, KYBER_SYMBYTES);
gen_a(a, publicseed);
PQCLEAN_KYBER512_AVX2_poly_getnoise_eta1_4x(skpv.vec + 0, skpv.vec + 1, e.vec + 0, e.vec + 1, noiseseed, 0, 1, 2, 3);
PQCLEAN_KYBER512_AVX2_polyvec_ntt(&skpv);
PQCLEAN_KYBER512_AVX2_polyvec_reduce(&skpv);
PQCLEAN_KYBER512_AVX2_polyvec_ntt(&e);
// matrix-vector multiplication
for (i = 0; i < KYBER_K; i++) {
PQCLEAN_KYBER512_AVX2_polyvec_basemul_acc_montgomery(&pkpv.vec[i], &a[i], &skpv);
PQCLEAN_KYBER512_AVX2_poly_tomont(&pkpv.vec[i]);
}
PQCLEAN_KYBER512_AVX2_polyvec_add(&pkpv, &pkpv, &e);
PQCLEAN_KYBER512_AVX2_polyvec_reduce(&pkpv);
pack_sk(sk, &skpv);
pack_pk(pk, &pkpv, publicseed);
}
/*************************************************
* Name: PQCLEAN_KYBER512_AVX2_indcpa_enc
*
* Description: Encryption function of the CPA-secure
* public-key encryption scheme underlying Kyber.
*
* Arguments: - uint8_t *c: pointer to output ciphertext
* (of length KYBER_INDCPA_BYTES bytes)
* - const uint8_t *m: pointer to input message
* (of length KYBER_INDCPA_MSGBYTES bytes)
* - const uint8_t *pk: pointer to input public key
* (of length KYBER_INDCPA_PUBLICKEYBYTES)
* - const uint8_t *coins: pointer to input random coins used as seed
* (of length KYBER_SYMBYTES) to deterministically
* generate all randomness
**************************************************/
void PQCLEAN_KYBER512_AVX2_indcpa_enc(uint8_t c[KYBER_INDCPA_BYTES],
const uint8_t m[KYBER_INDCPA_MSGBYTES],
const uint8_t pk[KYBER_INDCPA_PUBLICKEYBYTES],
const uint8_t coins[KYBER_SYMBYTES]) {
unsigned int i;
uint8_t seed[KYBER_SYMBYTES];
polyvec sp, pkpv, ep, at[KYBER_K], b;
poly v, k, epp;
unpack_pk(&pkpv, seed, pk);
PQCLEAN_KYBER512_AVX2_poly_frommsg(&k, m);
gen_at(at, seed);
PQCLEAN_KYBER512_AVX2_poly_getnoise_eta1122_4x(sp.vec + 0, sp.vec + 1, ep.vec + 0, ep.vec + 1, coins, 0, 1, 2, 3);
PQCLEAN_KYBER512_AVX2_poly_getnoise_eta2(&epp, coins, 4);
PQCLEAN_KYBER512_AVX2_polyvec_ntt(&sp);
// matrix-vector multiplication
for (i = 0; i < KYBER_K; i++) {
PQCLEAN_KYBER512_AVX2_polyvec_basemul_acc_montgomery(&b.vec[i], &at[i], &sp);
}
PQCLEAN_KYBER512_AVX2_polyvec_basemul_acc_montgomery(&v, &pkpv, &sp);
PQCLEAN_KYBER512_AVX2_polyvec_invntt_tomont(&b);
PQCLEAN_KYBER512_AVX2_poly_invntt_tomont(&v);
PQCLEAN_KYBER512_AVX2_polyvec_add(&b, &b, &ep);
PQCLEAN_KYBER512_AVX2_poly_add(&v, &v, &epp);
PQCLEAN_KYBER512_AVX2_poly_add(&v, &v, &k);
PQCLEAN_KYBER512_AVX2_polyvec_reduce(&b);
PQCLEAN_KYBER512_AVX2_poly_reduce(&v);
pack_ciphertext(c, &b, &v);
}
/*************************************************
* Name: PQCLEAN_KYBER512_AVX2_indcpa_dec
*
* Description: Decryption function of the CPA-secure
* public-key encryption scheme underlying Kyber.
*
* Arguments: - uint8_t *m: pointer to output decrypted message
* (of length KYBER_INDCPA_MSGBYTES)
* - const uint8_t *c: pointer to input ciphertext
* (of length KYBER_INDCPA_BYTES)
* - const uint8_t *sk: pointer to input secret key
* (of length KYBER_INDCPA_SECRETKEYBYTES)
**************************************************/
void PQCLEAN_KYBER512_AVX2_indcpa_dec(uint8_t m[KYBER_INDCPA_MSGBYTES],
const uint8_t c[KYBER_INDCPA_BYTES],
const uint8_t sk[KYBER_INDCPA_SECRETKEYBYTES]) {
polyvec b, skpv;
poly v, mp;
unpack_ciphertext(&b, &v, c);
unpack_sk(&skpv, sk);
PQCLEAN_KYBER512_AVX2_polyvec_ntt(&b);
PQCLEAN_KYBER512_AVX2_polyvec_basemul_acc_montgomery(&mp, &skpv, &b);
PQCLEAN_KYBER512_AVX2_poly_invntt_tomont(&mp);
PQCLEAN_KYBER512_AVX2_poly_sub(&mp, &v, &mp);
PQCLEAN_KYBER512_AVX2_poly_reduce(&mp);
PQCLEAN_KYBER512_AVX2_poly_tomsg(m, &mp);
}