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pqcrypto/crypto_kem/kyber1024/avx2/indcpa.c
Thom Wiggers f4bd312180 Adds AVX2 variants of Kyber512, Kyber768, Kyber1024 (#225)
* Integrate Kyber-AVX2 into PQClean

* Fix types and formatting in Kyber

* Workaround a valgrind crash

* Remove comment in shuffle.s

* Remove some extraneous truncations

* fixup! Fix types and formatting in Kyber
2019-09-10 11:45:01 +02:00

297 lines
12 KiB
C

#include "cbd.h"
#include "indcpa.h"
#include "ntt.h"
#include "poly.h"
#include "polyvec.h"
#include "randombytes.h"
#include "rejsample.h"
#include "symmetric.h"
/*************************************************
* Name: pack_pk
*
* Description: Serialize the public key as concatenation of the
* compressed and serialized vector of polynomials pk
* and the public seed used to generate the matrix A.
*
* Arguments: uint8_t *r: pointer to the output serialized public key
* const poly *pk: pointer to the input public-key polynomial
* const uint8_t *seed: pointer to the input public seed
**************************************************/
static void pack_pk(uint8_t *r, polyvec *pk, const uint8_t *seed) {
PQCLEAN_KYBER1024_AVX2_polyvec_tobytes(r, pk);
for (size_t i = 0; i < KYBER_SYMBYTES; i++) {
r[i + KYBER_POLYVECBYTES] = seed[i];
}
}
/*************************************************
* Name: unpack_pk
*
* Description: De-serialize and decompress public key from a byte array;
* approximate inverse of pack_pk
*
* Arguments: - polyvec *pk: pointer to output public-key vector of polynomials
* - 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, const uint8_t *packedpk) {
PQCLEAN_KYBER1024_AVX2_polyvec_frombytes(pk, packedpk);
for (size_t i = 0; i < KYBER_SYMBYTES; i++) {
seed[i] = packedpk[i + KYBER_POLYVECBYTES];
}
}
/*************************************************
* Name: pack_sk
*
* Description: Serialize the secret key
*
* Arguments: - uint8_t *r: pointer to output serialized secret key
* - const polyvec *sk: pointer to input vector of polynomials (secret key)
**************************************************/
static void pack_sk(uint8_t *r, polyvec *sk) {
PQCLEAN_KYBER1024_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) {
PQCLEAN_KYBER1024_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
*
* Arguments: uint8_t *r: pointer to the output serialized ciphertext
* const poly *pk: pointer to the input vector of polynomials b
* const uint8_t *seed: pointer to the input polynomial v
**************************************************/
static void pack_ciphertext(uint8_t *r, polyvec *b, poly *v) {
PQCLEAN_KYBER1024_AVX2_polyvec_compress(r, b);
PQCLEAN_KYBER1024_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) {
PQCLEAN_KYBER1024_AVX2_polyvec_decompress(b, c);
PQCLEAN_KYBER1024_AVX2_poly_decompress(v, c + KYBER_POLYVECCOMPRESSEDBYTES);
}
static size_t rej_uniform_ref(int16_t *r, size_t len, const uint8_t *buf, size_t buflen) {
unsigned int ctr, pos;
uint16_t val;
ctr = pos = 0;
while (ctr < len && pos + 2 <= buflen) {
val = (uint16_t)(buf[pos] | ((uint16_t)buf[pos + 1] << 8));
pos += 2;
if (val < 19 * KYBER_Q) {
val -= ((uint32_t)val * 20159 >> 26) * KYBER_Q; // Barrett reduction
r[ctr++] = (int16_t)val;
}
}
return ctr;
}
#define gen_a(A,B) gen_matrix(A,B,0)
#define gen_at(A,B) gen_matrix(A,B,1)
/*************************************************
* Name: 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
**************************************************/
#define GEN_MATRIX_MAXNBLOCKS ((530+XOF_BLOCKBYTES)/XOF_BLOCKBYTES) /* 530 is expected number of required bytes */
static void gen_matrix(polyvec *a, const uint8_t *seed, int transposed) {
uint16_t i;
size_t ctr0, ctr1, ctr2, ctr3, bufbytes;
union {
uint8_t x[4][XOF_BLOCKBYTES * GEN_MATRIX_MAXNBLOCKS];
__m256i _dummy;
} buf;
keccak4x_state state;
for (i = 0; i < 4; i++) {
if (transposed) {
PQCLEAN_KYBER1024_AVX2_kyber_shake128x4_absorb(
&state, seed, i + 0, i + 256, i + 512, i + 768);
} else {
PQCLEAN_KYBER1024_AVX2_kyber_shake128x4_absorb(
&state, seed, 256 * i + 0, 256 * i + 1, 256 * i + 2, 256 * i + 3);
}
PQCLEAN_KYBER1024_AVX2_shake128x4_squeezeblocks(
buf.x[0], buf.x[1], buf.x[2], buf.x[3], GEN_MATRIX_MAXNBLOCKS, &state);
bufbytes = GEN_MATRIX_MAXNBLOCKS * XOF_BLOCKBYTES;
ctr0 = PQCLEAN_KYBER1024_AVX2_rej_uniform(a[i].vec[0].coeffs, KYBER_N, buf.x[0], bufbytes);
ctr1 = PQCLEAN_KYBER1024_AVX2_rej_uniform(a[i].vec[1].coeffs, KYBER_N, buf.x[1], bufbytes);
ctr2 = PQCLEAN_KYBER1024_AVX2_rej_uniform(a[i].vec[2].coeffs, KYBER_N, buf.x[2], bufbytes);
ctr3 = PQCLEAN_KYBER1024_AVX2_rej_uniform(a[i].vec[3].coeffs, KYBER_N, buf.x[3], bufbytes);
while (ctr0 < KYBER_N || ctr1 < KYBER_N || ctr2 < KYBER_N || ctr3 < KYBER_N) {
PQCLEAN_KYBER1024_AVX2_shake128x4_squeezeblocks(buf.x[0], buf.x[1], buf.x[2], buf.x[3], 1, &state);
bufbytes = XOF_BLOCKBYTES;
ctr0 += rej_uniform_ref(a[i].vec[0].coeffs + ctr0, KYBER_N - ctr0, buf.x[0], bufbytes);
ctr1 += rej_uniform_ref(a[i].vec[1].coeffs + ctr1, KYBER_N - ctr1, buf.x[1], bufbytes);
ctr2 += rej_uniform_ref(a[i].vec[2].coeffs + ctr2, KYBER_N - ctr2, buf.x[2], bufbytes);
ctr3 += rej_uniform_ref(a[i].vec[3].coeffs + ctr3, KYBER_N - ctr3, buf.x[3], bufbytes);
}
PQCLEAN_KYBER1024_AVX2_poly_nttunpack(&a[i].vec[0]);
PQCLEAN_KYBER1024_AVX2_poly_nttunpack(&a[i].vec[1]);
PQCLEAN_KYBER1024_AVX2_poly_nttunpack(&a[i].vec[2]);
PQCLEAN_KYBER1024_AVX2_poly_nttunpack(&a[i].vec[3]);
}
}
/*************************************************
* Name: 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_KYBER1024_AVX2_indcpa_keypair(uint8_t *pk, uint8_t *sk) {
polyvec a[KYBER_K], skpv, e, pkpv;
uint8_t buf[2 * KYBER_SYMBYTES];
const uint8_t *publicseed = buf;
const uint8_t *noiseseed = buf + KYBER_SYMBYTES;
uint8_t nonce = 0;
randombytes(buf, KYBER_SYMBYTES);
hash_g(buf, buf, KYBER_SYMBYTES);
gen_a(a, publicseed);
PQCLEAN_KYBER1024_AVX2_poly_getnoise4x(skpv.vec + 0, skpv.vec + 1, skpv.vec + 2, skpv.vec + 3, noiseseed, nonce + 0, nonce + 1, nonce + 2, nonce + 3);
PQCLEAN_KYBER1024_AVX2_poly_getnoise4x(e.vec + 0, e.vec + 1, e.vec + 2, e.vec + 3, noiseseed, nonce + 4, nonce + 5, nonce + 6, nonce + 7);
PQCLEAN_KYBER1024_AVX2_polyvec_ntt(&skpv);
PQCLEAN_KYBER1024_AVX2_polyvec_ntt(&e);
// matrix-vector multiplication
for (size_t i = 0; i < KYBER_K; i++) {
PQCLEAN_KYBER1024_AVX2_polyvec_pointwise_acc(pkpv.vec + i, a + i, &skpv);
PQCLEAN_KYBER1024_AVX2_poly_frommont(pkpv.vec + i);
}
PQCLEAN_KYBER1024_AVX2_polyvec_add(&pkpv, &pkpv, &e);
PQCLEAN_KYBER1024_AVX2_polyvec_reduce(&pkpv);
pack_sk(sk, &skpv);
pack_pk(pk, &pkpv, publicseed);
}
/*************************************************
* Name: 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 bytes)
* - const uint8_t *coin: pointer to input random coins used as seed (of length KYBER_SYMBYTES bytes)
* to deterministically generate all randomness
**************************************************/
void PQCLEAN_KYBER1024_AVX2_indcpa_enc(uint8_t *c,
const uint8_t *m,
const uint8_t *pk,
const uint8_t *coins) {
polyvec at[KYBER_K], pkpv, sp, ep, bp;
poly k, v, epp;
uint8_t seed[KYBER_SYMBYTES];
uint8_t nonce = 0;
unpack_pk(&pkpv, seed, pk);
PQCLEAN_KYBER1024_AVX2_poly_frommsg(&k, m);
gen_at(at, seed);
PQCLEAN_KYBER1024_AVX2_poly_getnoise4x(sp.vec + 0, sp.vec + 1, sp.vec + 2, sp.vec + 3, coins, nonce + 0, nonce + 1, nonce + 2, nonce + 3);
PQCLEAN_KYBER1024_AVX2_poly_getnoise4x(ep.vec + 0, ep.vec + 1, ep.vec + 2, ep.vec + 3, coins, nonce + 4, nonce + 5, nonce + 6, nonce + 7);
PQCLEAN_KYBER1024_AVX2_poly_getnoise(&epp, coins, nonce + 8);
PQCLEAN_KYBER1024_AVX2_polyvec_ntt(&sp);
// matrix-vector multiplication
for (size_t i = 0; i < KYBER_K; i++) {
PQCLEAN_KYBER1024_AVX2_polyvec_pointwise_acc(bp.vec + i, at + i, &sp);
}
PQCLEAN_KYBER1024_AVX2_polyvec_pointwise_acc(&v, &pkpv, &sp);
PQCLEAN_KYBER1024_AVX2_polyvec_invntt(&bp);
PQCLEAN_KYBER1024_AVX2_poly_invntt(&v);
PQCLEAN_KYBER1024_AVX2_polyvec_add(&bp, &bp, &ep);
PQCLEAN_KYBER1024_AVX2_poly_add(&v, &v, &epp);
PQCLEAN_KYBER1024_AVX2_poly_add(&v, &v, &k);
PQCLEAN_KYBER1024_AVX2_polyvec_reduce(&bp);
PQCLEAN_KYBER1024_AVX2_poly_reduce(&v);
pack_ciphertext(c, &bp, &v);
}
/*************************************************
* Name: 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_KYBER1024_AVX2_indcpa_dec(uint8_t *m,
const uint8_t *c,
const uint8_t *sk) {
polyvec bp, skpv;
poly v, mp;
unpack_ciphertext(&bp, &v, c);
unpack_sk(&skpv, sk);
PQCLEAN_KYBER1024_AVX2_polyvec_ntt(&bp);
PQCLEAN_KYBER1024_AVX2_polyvec_pointwise_acc(&mp, &skpv, &bp);
PQCLEAN_KYBER1024_AVX2_poly_invntt(&mp);
PQCLEAN_KYBER1024_AVX2_poly_sub(&mp, &v, &mp);
PQCLEAN_KYBER1024_AVX2_poly_reduce(&mp);
PQCLEAN_KYBER1024_AVX2_poly_tomsg(m, &mp);
}