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pqcrypto/crypto_sign/dilithium-iii/clean/poly.c
Joost Rijneveld 879574b695
Include name of implementation in namespace
2019-02-27 09:18:38 +01:00

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#include "poly.h"
#include "fips202.h"
#include "ntt.h"
#include "params.h"
#include "reduce.h"
#include "rounding.h"
#include <stdint.h>
/*************************************************
* Name: poly_reduce
*
* Description: Reduce all coefficients of input polynomial to representative
* in [0,2*Q[.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_reduce(poly *a) {
unsigned int i;
for (i = 0; i < N; ++i) {
a->coeffs[i] = PQCLEAN_DILITHIUMIII_CLEAN_reduce32(a->coeffs[i]);
}
}
/*************************************************
* Name: poly_csubq
*
* Description: For all coefficients of input polynomial subtract Q if
* coefficient is bigger than Q.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_csubq(poly *a) {
unsigned int i;
for (i = 0; i < N; ++i) {
a->coeffs[i] = PQCLEAN_DILITHIUMIII_CLEAN_csubq(a->coeffs[i]);
}
}
/*************************************************
* Name: poly_freeze
*
* Description: Reduce all coefficients of the polynomial to standard
* representatives.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_freeze(poly *a) {
unsigned int i;
for (i = 0; i < N; ++i) {
a->coeffs[i] = PQCLEAN_DILITHIUMIII_CLEAN_freeze(a->coeffs[i]);
}
}
/*************************************************
* Name: poly_add
*
* Description: Add polynomials. No modular reduction is performed.
*
* Arguments: - poly *c: pointer to output polynomial
* - const poly *a: pointer to first summand
* - const poly *b: pointer to second summand
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_add(poly *c, const poly *a, const poly *b) {
unsigned int i;
for (i = 0; i < N; ++i) {
c->coeffs[i] = a->coeffs[i] + b->coeffs[i];
}
}
/*************************************************
* Name: poly_sub
*
* Description: Subtract polynomials. Assumes coefficients of second input
* polynomial to be less than 2*Q. No modular reduction is
* performed.
*
* Arguments: - poly *c: pointer to output polynomial
* - const poly *a: pointer to first input polynomial
* - const poly *b: pointer to second input polynomial to be
* subtraced from first input polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_sub(poly *c, const poly *a, const poly *b) {
unsigned int i;
for (i = 0; i < N; ++i) {
c->coeffs[i] = a->coeffs[i] + 2 * Q - b->coeffs[i];
}
}
/*************************************************
* Name: poly_neg
*
* Description: Negate polynomial. Assumes input coefficients to be standard
* representatives.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_neg(poly *a) {
unsigned int i;
for (i = 0; i < N; ++i) {
a->coeffs[i] = Q - a->coeffs[i];
}
}
/*************************************************
* Name: poly_shiftl
*
* Description: Multiply polynomial by 2^k without modular reduction. Assumes
* input coefficients to be less than 2^{32-k}.
*
* Arguments: - poly *a: pointer to input/output polynomial
* - unsigned int k: exponent
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_shiftl(poly *a, unsigned int k) {
unsigned int i;
for (i = 0; i < N; ++i) {
a->coeffs[i] <<= k;
}
}
/*************************************************
* Name: poly_ntt
*
* Description: Forward NTT. Output coefficients can be up to 16*Q larger than
* input coefficients.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_ntt(poly *a) {
PQCLEAN_DILITHIUMIII_CLEAN_ntt(a->coeffs);
}
/*************************************************
* Name: poly_invntt_montgomery
*
* Description: Inverse NTT and multiplication with 2^{32}. Input coefficients
* need to be less than 2*Q. Output coefficients are less than 2*Q.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_invntt_montgomery(poly *a) {
PQCLEAN_DILITHIUMIII_CLEAN_invntt_frominvmont(a->coeffs);
}
/*************************************************
* Name: poly_pointwise_invmontgomery
*
* Description: Pointwise multiplication of polynomials in NTT domain
* representation and multiplication of resulting polynomial
* with 2^{-32}. Output coefficients are less than 2*Q if input
* coefficient are less than 22*Q.
*
* Arguments: - poly *c: pointer to output polynomial
* - const poly *a: pointer to first input polynomial
* - const poly *b: pointer to second input polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_pointwise_invmontgomery(poly *c, const poly *a,
const poly *b) {
unsigned int i;
for (i = 0; i < N; ++i) {
c->coeffs[i] = PQCLEAN_DILITHIUMIII_CLEAN_montgomery_reduce(
(uint64_t)a->coeffs[i] * b->coeffs[i]);
}
}
/*************************************************
* Name: poly_power2round
*
* Description: For all coefficients c of the input polynomial,
* compute c0, c1 such that c mod Q = c1*2^D + c0
* with -2^{D-1} < c0 <= 2^{D-1}. Assumes coefficients to be
* standard representatives.
*
* Arguments: - poly *a1: pointer to output polynomial with coefficients c1
* - poly *a0: pointer to output polynomial with coefficients Q +
*a0
* - const poly *v: pointer to input polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_power2round(poly *a1, poly *a0, const poly *a) {
unsigned int i;
for (i = 0; i < N; ++i) {
a1->coeffs[i] =
PQCLEAN_DILITHIUMIII_CLEAN_power2round(a->coeffs[i], a0->coeffs + i);
}
}
/*************************************************
* Name: poly_decompose
*
* Description: For all coefficients c of the input polynomial,
* compute high and low bits c0, c1 such c mod Q = c1*ALPHA + c0
* with -ALPHA/2 < c0 <= ALPHA/2 except c1 = (Q-1)/ALPHA where we
* set c1 = 0 and -ALPHA/2 <= c0 = c mod Q - Q < 0.
* Assumes coefficients to be standard representatives.
*
* Arguments: - poly *a1: pointer to output polynomial with coefficients c1
* - poly *a0: pointer to output polynomial with coefficients Q +
*a0
* - const poly *c: pointer to input polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_decompose(poly *a1, poly *a0, const poly *a) {
unsigned int i;
for (i = 0; i < N; ++i) {
a1->coeffs[i] =
PQCLEAN_DILITHIUMIII_CLEAN_decompose(a->coeffs[i], a0->coeffs + i);
}
}
/*************************************************
* Name: poly_make_hint
*
* Description: Compute hint polynomial. The coefficients of which indicate
* whether the high bits of the corresponding coefficients
* of the first input polynomial and of the sum of the input
* polynomials differ.
*
* Arguments: - poly *h: pointer to output hint polynomial
* - const poly *a: pointer to first input polynomial
* - const poly *b: pointer to second input polynomial
*
* Returns number of 1 bits.
**************************************************/
unsigned int PQCLEAN_DILITHIUMIII_CLEAN_poly_make_hint(poly *h, const poly *a,
const poly *b) {
unsigned int i, s = 0;
for (i = 0; i < N; ++i) {
h->coeffs[i] =
PQCLEAN_DILITHIUMIII_CLEAN_make_hint(a->coeffs[i], b->coeffs[i]);
s += h->coeffs[i];
}
return s;
}
/*************************************************
* Name: poly_use_hint
*
* Description: Use hint polynomial to correct the high bits of a polynomial.
*
* Arguments: - poly *a: pointer to output polynomial with corrected high bits
* - const poly *b: pointer to input polynomial
* - const poly *h: pointer to input hint polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_use_hint(poly *a, const poly *b, const poly *h) {
unsigned int i;
for (i = 0; i < N; ++i) {
a->coeffs[i] =
PQCLEAN_DILITHIUMIII_CLEAN_use_hint(b->coeffs[i], h->coeffs[i]);
}
}
/*************************************************
* Name: poly_chknorm
*
* Description: Check infinity norm of polynomial against given bound.
* Assumes input coefficients to be standard representatives.
*
* Arguments: - const poly *a: pointer to polynomial
* - uint32_t B: norm bound
*
* Returns 0 if norm is strictly smaller than B and 1 otherwise.
**************************************************/
int PQCLEAN_DILITHIUMIII_CLEAN_poly_chknorm(const poly *a, uint32_t B) {
unsigned int i;
int32_t t;
/* It is ok to leak which coefficient violates the bound since
the probability for each coefficient is independent of secret
data but we must not leak the sign of the centralized representative. */
for (i = 0; i < N; ++i) {
/* Absolute value of centralized representative */
t = (Q - 1) / 2 - a->coeffs[i];
t ^= (t >> 31);
t = (Q - 1) / 2 - t;
if ((uint32_t)t >= B) {
return 1;
}
}
return 0;
}
/*************************************************
* Name: poly_uniform
*
* Description: Sample uniformly random polynomial using stream of random bytes.
* Assumes that enough random bytes are given (e.g.
* 5*SHAKE128_RATE bytes).
*
* Arguments: - poly *a: pointer to output polynomial
* - const unsigned char *buf: array of random bytes
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_uniform(poly *a, const unsigned char *buf) {
unsigned int ctr, pos;
uint32_t t;
ctr = pos = 0;
while (ctr < N) {
t = buf[pos++];
t |= (uint32_t)buf[pos++] << 8;
t |= (uint32_t)buf[pos++] << 16;
t &= 0x7FFFFF;
if (t < Q) {
a->coeffs[ctr++] = t;
}
}
}
/*************************************************
* Name: rej_eta
*
* Description: Sample uniformly random coefficients in [-ETA, ETA] by
* performing rejection sampling using array of random bytes.
*
* Arguments: - uint32_t *a: pointer to output array (allocated)
* - unsigned int len: number of coefficients to be sampled
* - const unsigned char *buf: array of random bytes
* - unsigned int buflen: length of array of random bytes
*
* Returns number of sampled coefficients. Can be smaller than len if not enough
* random bytes were given.
**************************************************/
static unsigned int rej_eta(uint32_t *a, unsigned int len,
const unsigned char *buf, unsigned int buflen) {
#if ETA > 7
#error "rej_eta() assumes ETA <= 7"
#endif
unsigned int ctr, pos;
unsigned char t0, t1;
ctr = pos = 0;
while (ctr < len && pos < buflen) {
#if ETA <= 3
t0 = buf[pos] & 0x07;
t1 = buf[pos++] >> 5;
#else
t0 = buf[pos] & 0x0F;
t1 = buf[pos++] >> 4;
#endif
if (t0 <= 2 * ETA) {
a[ctr++] = Q + ETA - t0;
}
if (t1 <= 2 * ETA && ctr < len) {
a[ctr++] = Q + ETA - t1;
}
}
return ctr;
}
/*************************************************
* Name: poly_uniform_eta
*
* Description: Sample polynomial with uniformly random coefficients
* in [-ETA,ETA] by performing rejection sampling using the
* output stream from SHAKE256(seed|nonce).
*
* Arguments: - poly *a: pointer to output polynomial
* - const unsigned char seed[]: byte array with seed of length
* SEEDBYTES
* - unsigned char nonce: nonce byte
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_uniform_eta(poly *a,
const unsigned char seed[SEEDBYTES],
unsigned char nonce) {
unsigned int i, ctr;
unsigned char inbuf[SEEDBYTES + 1];
/* Probability that we need more than 2 blocks: < 2^{-84}
Probability that we need more than 3 blocks: < 2^{-352} */
unsigned char outbuf[2 * SHAKE256_RATE];
uint64_t state[25];
for (i = 0; i < SEEDBYTES; ++i) {
inbuf[i] = seed[i];
}
inbuf[SEEDBYTES] = nonce;
shake256_absorb(state, inbuf, SEEDBYTES + 1);
shake256_squeezeblocks(outbuf, 2, state);
ctr = rej_eta(a->coeffs, N, outbuf, 2 * SHAKE256_RATE);
if (ctr < N) {
shake256_squeezeblocks(outbuf, 1, state);
rej_eta(a->coeffs + ctr, N - ctr, outbuf, SHAKE256_RATE);
}
}
/*************************************************
* Name: rej_gamma1m1
*
* Description: Sample uniformly random coefficients
* in [-(GAMMA1 - 1), GAMMA1 - 1] by performing rejection sampling
* using array of random bytes.
*
* Arguments: - uint32_t *a: pointer to output array (allocated)
* - unsigned int len: number of coefficients to be sampled
* - const unsigned char *buf: array of random bytes
* - unsigned int buflen: length of array of random bytes
*
* Returns number of sampled coefficients. Can be smaller than len if not enough
* random bytes were given.
**************************************************/
static unsigned int rej_gamma1m1(uint32_t *a, unsigned int len,
const unsigned char *buf,
unsigned int buflen) {
#if GAMMA1 > (1 << 19)
#error "rej_gamma1m1() assumes GAMMA1 - 1 fits in 19 bits"
#endif
unsigned int ctr, pos;
uint32_t t0, t1;
ctr = pos = 0;
while (ctr < len && pos + 5 <= buflen) {
t0 = buf[pos];
t0 |= (uint32_t)buf[pos + 1] << 8;
t0 |= (uint32_t)buf[pos + 2] << 16;
t0 &= 0xFFFFF;
t1 = buf[pos + 2] >> 4;
t1 |= (uint32_t)buf[pos + 3] << 4;
t1 |= (uint32_t)buf[pos + 4] << 12;
pos += 5;
if (t0 <= 2 * GAMMA1 - 2) {
a[ctr++] = Q + GAMMA1 - 1 - t0;
}
if (t1 <= 2 * GAMMA1 - 2 && ctr < len) {
a[ctr++] = Q + GAMMA1 - 1 - t1;
}
}
return ctr;
}
/*************************************************
* Name: poly_uniform_gamma1m1
*
* Description: Sample polynomial with uniformly random coefficients
* in [-(GAMMA1 - 1), GAMMA1 - 1] by performing rejection
* sampling on output stream of SHAKE256(seed|nonce).
*
* Arguments: - poly *a: pointer to output polynomial
* - const unsigned char seed[]: byte array with seed of length
* SEEDBYTES + CRHBYTES
* - uint16_t nonce: 16-bit nonce
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_poly_uniform_gamma1m1(
poly *a, const unsigned char seed[SEEDBYTES + CRHBYTES], uint16_t nonce) {
unsigned int i, ctr;
unsigned char inbuf[SEEDBYTES + CRHBYTES + 2];
/* Probability that we need more than 5 blocks: < 2^{-81}
Probability that we need more than 6 blocks: < 2^{-467} */
unsigned char outbuf[5 * SHAKE256_RATE];
uint64_t state[25];
for (i = 0; i < SEEDBYTES + CRHBYTES; ++i) {
inbuf[i] = seed[i];
}
inbuf[SEEDBYTES + CRHBYTES] = nonce & 0xFF;
inbuf[SEEDBYTES + CRHBYTES + 1] = nonce >> 8;
shake256_absorb(state, inbuf, SEEDBYTES + CRHBYTES + 2);
shake256_squeezeblocks(outbuf, 5, state);
ctr = rej_gamma1m1(a->coeffs, N, outbuf, 5 * SHAKE256_RATE);
if (ctr < N) {
/* There are no bytes left in outbuf
since 5*SHAKE256_RATE is divisible by 5 */
shake256_squeezeblocks(outbuf, 1, state);
rej_gamma1m1(a->coeffs + ctr, N - ctr, outbuf, SHAKE256_RATE);
}
}
/*************************************************
* Name: polyeta_pack
*
* Description: Bit-pack polynomial with coefficients in [-ETA,ETA].
* Input coefficients are assumed to lie in [Q-ETA,Q+ETA].
*
* Arguments: - unsigned char *r: pointer to output byte array with at least
* POLETA_SIZE_PACKED bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_polyeta_pack(unsigned char *r, const poly *a) {
#if ETA > 7
#error "polyeta_pack() assumes ETA <= 7"
#endif
unsigned int i;
unsigned char t[8];
#if ETA <= 3
for (i = 0; i < N / 8; ++i) {
t[0] = Q + ETA - a->coeffs[8 * i + 0];
t[1] = Q + ETA - a->coeffs[8 * i + 1];
t[2] = Q + ETA - a->coeffs[8 * i + 2];
t[3] = Q + ETA - a->coeffs[8 * i + 3];
t[4] = Q + ETA - a->coeffs[8 * i + 4];
t[5] = Q + ETA - a->coeffs[8 * i + 5];
t[6] = Q + ETA - a->coeffs[8 * i + 6];
t[7] = Q + ETA - a->coeffs[8 * i + 7];
r[3 * i + 0] = t[0];
r[3 * i + 0] |= t[1] << 3;
r[3 * i + 0] |= t[2] << 6;
r[3 * i + 1] = t[2] >> 2;
r[3 * i + 1] |= t[3] << 1;
r[3 * i + 1] |= t[4] << 4;
r[3 * i + 1] |= t[5] << 7;
r[3 * i + 2] = t[5] >> 1;
r[3 * i + 2] |= t[6] << 2;
r[3 * i + 2] |= t[7] << 5;
}
#else
for (i = 0; i < N / 2; ++i) {
t[0] = Q + ETA - a->coeffs[2 * i + 0];
t[1] = Q + ETA - a->coeffs[2 * i + 1];
r[i] = t[0] | (t[1] << 4);
}
#endif
}
/*************************************************
* Name: polyeta_unpack
*
* Description: Unpack polynomial with coefficients in [-ETA,ETA].
* Output coefficients lie in [Q-ETA,Q+ETA].
*
* Arguments: - poly *r: pointer to output polynomial
* - const unsigned char *a: byte array with bit-packed polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_polyeta_unpack(poly *r, const unsigned char *a) {
unsigned int i;
#if ETA <= 3
for (i = 0; i < N / 8; ++i) {
r->coeffs[8 * i + 0] = a[3 * i + 0] & 0x07;
r->coeffs[8 * i + 1] = (a[3 * i + 0] >> 3) & 0x07;
r->coeffs[8 * i + 2] =
(a[3 * i + 0] >> 6) | ((a[3 * i + 1] & 0x01) << 2);
r->coeffs[8 * i + 3] = (a[3 * i + 1] >> 1) & 0x07;
r->coeffs[8 * i + 4] = (a[3 * i + 1] >> 4) & 0x07;
r->coeffs[8 * i + 5] =
(a[3 * i + 1] >> 7) | ((a[3 * i + 2] & 0x03) << 1);
r->coeffs[8 * i + 6] = (a[3 * i + 2] >> 2) & 0x07;
r->coeffs[8 * i + 7] = (a[3 * i + 2] >> 5);
r->coeffs[8 * i + 0] = Q + ETA - r->coeffs[8 * i + 0];
r->coeffs[8 * i + 1] = Q + ETA - r->coeffs[8 * i + 1];
r->coeffs[8 * i + 2] = Q + ETA - r->coeffs[8 * i + 2];
r->coeffs[8 * i + 3] = Q + ETA - r->coeffs[8 * i + 3];
r->coeffs[8 * i + 4] = Q + ETA - r->coeffs[8 * i + 4];
r->coeffs[8 * i + 5] = Q + ETA - r->coeffs[8 * i + 5];
r->coeffs[8 * i + 6] = Q + ETA - r->coeffs[8 * i + 6];
r->coeffs[8 * i + 7] = Q + ETA - r->coeffs[8 * i + 7];
}
#else
for (i = 0; i < N / 2; ++i) {
r->coeffs[2 * i + 0] = a[i] & 0x0F;
r->coeffs[2 * i + 1] = a[i] >> 4;
r->coeffs[2 * i + 0] = Q + ETA - r->coeffs[2 * i + 0];
r->coeffs[2 * i + 1] = Q + ETA - r->coeffs[2 * i + 1];
}
#endif
}
/*************************************************
* Name: polyt1_pack
*
* Description: Bit-pack polynomial t1 with coefficients fitting in 9 bits.
* Input coefficients are assumed to be standard representatives.
*
* Arguments: - unsigned char *r: pointer to output byte array with at least
* POLT1_SIZE_PACKED bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_polyt1_pack(unsigned char *r, const poly *a) {
#if D != 14
#error "polyt1_pack() assumes D == 14"
#endif
unsigned int i;
for (i = 0; i < N / 8; ++i) {
r[9 * i + 0] = a->coeffs[8 * i + 0] & 0xFF;
r[9 * i + 1] = (a->coeffs[8 * i + 0] >> 8) | ((a->coeffs[8 * i + 1] & 0x7F) << 1);
r[9 * i + 2] = (a->coeffs[8 * i + 1] >> 7) | ((a->coeffs[8 * i + 2] & 0x3F) << 2);
r[9 * i + 3] = (a->coeffs[8 * i + 2] >> 6) | ((a->coeffs[8 * i + 3] & 0x1F) << 3);
r[9 * i + 4] = (a->coeffs[8 * i + 3] >> 5) | ((a->coeffs[8 * i + 4] & 0x0F) << 4);
r[9 * i + 5] = (a->coeffs[8 * i + 4] >> 4) | ((a->coeffs[8 * i + 5] & 0x07) << 5);
r[9 * i + 6] = (a->coeffs[8 * i + 5] >> 3) | ((a->coeffs[8 * i + 6] & 0x03) << 6);
r[9 * i + 7] = (a->coeffs[8 * i + 6] >> 2) | ((a->coeffs[8 * i + 7] & 0x01) << 7);
r[9 * i + 8] = a->coeffs[8 * i + 7] >> 1;
}
}
/*************************************************
* Name: polyt1_unpack
*
* Description: Unpack polynomial t1 with 9-bit coefficients.
* Output coefficients are standard representatives.
*
* Arguments: - poly *r: pointer to output polynomial
* - const unsigned char *a: byte array with bit-packed polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_polyt1_unpack(poly *r, const unsigned char *a) {
unsigned int i;
for (i = 0; i < N / 8; ++i) {
r->coeffs[8 * i + 0] = a[9 * i + 0] | ((uint32_t)(a[9 * i + 1] & 0x01) << 8);
r->coeffs[8 * i + 1] = (a[9 * i + 1] >> 1) | ((uint32_t)(a[9 * i + 2] & 0x03) << 7);
r->coeffs[8 * i + 2] = (a[9 * i + 2] >> 2) | ((uint32_t)(a[9 * i + 3] & 0x07) << 6);
r->coeffs[8 * i + 3] = (a[9 * i + 3] >> 3) | ((uint32_t)(a[9 * i + 4] & 0x0F) << 5);
r->coeffs[8 * i + 4] = (a[9 * i + 4] >> 4) | ((uint32_t)(a[9 * i + 5] & 0x1F) << 4);
r->coeffs[8 * i + 5] = (a[9 * i + 5] >> 5) | ((uint32_t)(a[9 * i + 6] & 0x3F) << 3);
r->coeffs[8 * i + 6] = (a[9 * i + 6] >> 6) | ((uint32_t)(a[9 * i + 7] & 0x7F) << 2);
r->coeffs[8 * i + 7] = (a[9 * i + 7] >> 7) | ((uint32_t)(a[9 * i + 8] & 0xFF) << 1);
}
}
/*************************************************
* Name: polyt0_pack
*
* Description: Bit-pack polynomial t0 with coefficients in ]-2^{D-1}, 2^{D-1}].
* Input coefficients are assumed to lie in ]Q-2^{D-1}, Q+2^{D-1}].
*
* Arguments: - unsigned char *r: pointer to output byte array with at least
* POLT0_SIZE_PACKED bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_polyt0_pack(unsigned char *r, const poly *a) {
unsigned int i;
uint32_t t[4];
for (i = 0; i < N / 4; ++i) {
t[0] = Q + (1 << (D - 1)) - a->coeffs[4 * i + 0];
t[1] = Q + (1 << (D - 1)) - a->coeffs[4 * i + 1];
t[2] = Q + (1 << (D - 1)) - a->coeffs[4 * i + 2];
t[3] = Q + (1 << (D - 1)) - a->coeffs[4 * i + 3];
r[7 * i + 0] = t[0];
r[7 * i + 1] = t[0] >> 8;
r[7 * i + 1] |= t[1] << 6;
r[7 * i + 2] = t[1] >> 2;
r[7 * i + 3] = t[1] >> 10;
r[7 * i + 3] |= t[2] << 4;
r[7 * i + 4] = t[2] >> 4;
r[7 * i + 5] = t[2] >> 12;
r[7 * i + 5] |= t[3] << 2;
r[7 * i + 6] = t[3] >> 6;
}
}
/*************************************************
* Name: polyt0_unpack
*
* Description: Unpack polynomial t0 with coefficients in ]-2^{D-1}, 2^{D-1}].
* Output coefficients lie in ]Q-2^{D-1},Q+2^{D-1}].
*
* Arguments: - poly *r: pointer to output polynomial
* - const unsigned char *a: byte array with bit-packed polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_polyt0_unpack(poly *r, const unsigned char *a) {
unsigned int i;
for (i = 0; i < N / 4; ++i) {
r->coeffs[4 * i + 0] = a[7 * i + 0];
r->coeffs[4 * i + 0] |= (uint32_t)(a[7 * i + 1] & 0x3F) << 8;
r->coeffs[4 * i + 1] = a[7 * i + 1] >> 6;
r->coeffs[4 * i + 1] |= (uint32_t)a[7 * i + 2] << 2;
r->coeffs[4 * i + 1] |= (uint32_t)(a[7 * i + 3] & 0x0F) << 10;
r->coeffs[4 * i + 2] = a[7 * i + 3] >> 4;
r->coeffs[4 * i + 2] |= (uint32_t)a[7 * i + 4] << 4;
r->coeffs[4 * i + 2] |= (uint32_t)(a[7 * i + 5] & 0x03) << 12;
r->coeffs[4 * i + 3] = a[7 * i + 5] >> 2;
r->coeffs[4 * i + 3] |= (uint32_t)a[7 * i + 6] << 6;
r->coeffs[4 * i + 0] = Q + (1 << (D - 1)) - r->coeffs[4 * i + 0];
r->coeffs[4 * i + 1] = Q + (1 << (D - 1)) - r->coeffs[4 * i + 1];
r->coeffs[4 * i + 2] = Q + (1 << (D - 1)) - r->coeffs[4 * i + 2];
r->coeffs[4 * i + 3] = Q + (1 << (D - 1)) - r->coeffs[4 * i + 3];
}
}
/*************************************************
* Name: polyz_pack
*
* Description: Bit-pack polynomial z with coefficients
* in [-(GAMMA1 - 1), GAMMA1 - 1].
* Input coefficients are assumed to be standard representatives.
*
* Arguments: - unsigned char *r: pointer to output byte array with at least
* POLZ_SIZE_PACKED bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_polyz_pack(unsigned char *r, const poly *a) {
#if GAMMA1 > (1 << 19)
#error "polyz_pack() assumes GAMMA1 <= 2^{19}"
#endif
unsigned int i;
uint32_t t[2];
for (i = 0; i < N / 2; ++i) {
/* Map to {0,...,2*GAMMA1 - 2} */
t[0] = GAMMA1 - 1 - a->coeffs[2 * i + 0];
t[0] += ((int32_t)t[0] >> 31) & Q;
t[1] = GAMMA1 - 1 - a->coeffs[2 * i + 1];
t[1] += ((int32_t)t[1] >> 31) & Q;
r[5 * i + 0] = t[0];
r[5 * i + 1] = t[0] >> 8;
r[5 * i + 2] = t[0] >> 16;
r[5 * i + 2] |= t[1] << 4;
r[5 * i + 3] = t[1] >> 4;
r[5 * i + 4] = t[1] >> 12;
}
}
/*************************************************
* Name: polyz_unpack
*
* Description: Unpack polynomial z with coefficients
* in [-(GAMMA1 - 1), GAMMA1 - 1].
* Output coefficients are standard representatives.
*
* Arguments: - poly *r: pointer to output polynomial
* - const unsigned char *a: byte array with bit-packed polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_polyz_unpack(poly *r, const unsigned char *a) {
unsigned int i;
for (i = 0; i < N / 2; ++i) {
r->coeffs[2 * i + 0] = a[5 * i + 0];
r->coeffs[2 * i + 0] |= (uint32_t)a[5 * i + 1] << 8;
r->coeffs[2 * i + 0] |= (uint32_t)(a[5 * i + 2] & 0x0F) << 16;
r->coeffs[2 * i + 1] = a[5 * i + 2] >> 4;
r->coeffs[2 * i + 1] |= (uint32_t)a[5 * i + 3] << 4;
r->coeffs[2 * i + 1] |= (uint32_t)a[5 * i + 4] << 12;
r->coeffs[2 * i + 0] = GAMMA1 - 1 - r->coeffs[2 * i + 0];
r->coeffs[2 * i + 0] += ((int32_t)r->coeffs[2 * i + 0] >> 31) & Q;
r->coeffs[2 * i + 1] = GAMMA1 - 1 - r->coeffs[2 * i + 1];
r->coeffs[2 * i + 1] += ((int32_t)r->coeffs[2 * i + 1] >> 31) & Q;
}
}
/*************************************************
* Name: polyw1_pack
*
* Description: Bit-pack polynomial w1 with coefficients in [0, 15].
* Input coefficients are assumed to be standard representatives.
*
* Arguments: - unsigned char *r: pointer to output byte array with at least
* POLW1_SIZE_PACKED bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void PQCLEAN_DILITHIUMIII_CLEAN_polyw1_pack(unsigned char *r, const poly *a) {
unsigned int i;
for (i = 0; i < N / 2; ++i) {
r[i] = a->coeffs[2 * i + 0] | (a->coeffs[2 * i + 1] << 4);
}
}
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