Revision 066d0de359cbfdeac99b8077fd6473f188985e01 authored by Richard Petri on 20 July 2022, 07:57:55 UTC, committed by Richard Petri on 20 July 2022, 07:57:55 UTC
1 parent 26f810d
poly.c
#include <stdint.h>
#include "params.h"
#include "poly.h"
#include "vector.h"
#include "ntt.h"
#include "pointwise_mont.h"
#include "rounding.h"
#include "symmetric.h"
#include <stdio.h>
#include "hal.h"
#ifdef DBENCH
#include "test/cpucycles.h"
extern const uint64_t timing_overhead;
extern uint64_t *tred, *tadd, *tmul, *tround, *tsample, *tpack;
#define DBENCH_START() uint64_t time = cpucycles()
#define DBENCH_STOP(t) t += cpucycles() - time - timing_overhead
#else
#define DBENCH_START()
#define DBENCH_STOP(t)
#endif
/*************************************************
* Name: poly_reduce
*
* Description: Inplace reduction of all coefficients of polynomial to
* representative in [-6283009,6283007].
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void poly_reduce(poly *a) {
asm_reduce32(a->coeffs);
}
/*************************************************
* Name: poly_caddq
*
* Description: For all coefficients of in/out polynomial add Q if
* coefficient is negative.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void poly_caddq(poly *a) {
asm_caddq(a->coeffs);
}
#if 0
/*************************************************
* Name: poly_freeze
*
* Description: Inplace reduction of all coefficients of polynomial to
* standard representatives.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void poly_freeze(poly *a) {
asm_freeze(a->coeffs);
}
#endif
/*************************************************
* 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 poly_add(poly *c, const poly *a, const poly *b) {
unsigned int i;
DBENCH_START();
for(i = 0; i < N; ++i)
c->coeffs[i] = a->coeffs[i] + b->coeffs[i];
DBENCH_STOP(*tadd);
}
/*************************************************
* Name: poly_sub
*
* Description: Subtract polynomials. 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 poly_sub(poly *c, const poly *a, const poly *b) {
unsigned int i;
DBENCH_START();
for(i = 0; i < N; ++i)
c->coeffs[i] = a->coeffs[i] - b->coeffs[i];
DBENCH_STOP(*tadd);
}
/*************************************************
* Name: poly_shiftl
*
* Description: Multiply polynomial by 2^D without modular reduction. Assumes
* input coefficients to be less than 2^{31-D} in absolute value.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void poly_shiftl(poly *a) {
unsigned int i;
DBENCH_START();
for(i = 0; i < N; ++i)
a->coeffs[i] <<= D;
DBENCH_STOP(*tmul);
}
/*************************************************
* Name: poly_ntt
*
* Description: Inplace forward NTT. Coefficients can grow by
* 8*Q in absolute value.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void poly_ntt(poly *a) {
DBENCH_START();
ntt(a->coeffs);
DBENCH_STOP(*tmul);
}
/*************************************************
* Name: poly_invntt_tomont
*
* Description: Inplace inverse NTT and multiplication by 2^{32}.
* Input coefficients need to be less than Q in absolute
* value and output coefficients are again bounded by Q.
*
* Arguments: - poly *a: pointer to input/output polynomial
**************************************************/
void poly_invntt_tomont(poly *a) {
DBENCH_START();
invntt_tomont(a->coeffs);
DBENCH_STOP(*tmul);
}
/*************************************************
* Name: poly_pointwise_montgomery
*
* Description: Pointwise multiplication of polynomials in NTT domain
* representation and multiplication of resulting polynomial
* by 2^{-32}.
*
* Arguments: - poly *c: pointer to output polynomial
* - const poly *a: pointer to first input polynomial
* - const poly *b: pointer to second input polynomial
**************************************************/
void poly_pointwise_montgomery(poly *c, const poly *a, const poly *b) {
DBENCH_START();
asm_pointwise_montgomery(c->coeffs, a->coeffs, b->coeffs);
DBENCH_STOP(*tmul);
}
/*************************************************
* Name: poly_pointwise_acc_montgomery
*
* Description: Pointwise multiplication of polynomials in NTT domain
* representation, multiplication of resulting polynomial
* by 2^{-32} and accumulate.
*
* Arguments: - poly *c: pointer to output (accumulating) polynomial
* - const poly *a: pointer to first input polynomial
* - const poly *b: pointer to second input polynomial
**************************************************/
void poly_pointwise_acc_montgomery(poly *c, const poly *a, const poly *b) {
DBENCH_START();
asm_pointwise_acc_montgomery(c->coeffs, a->coeffs, b->coeffs);
DBENCH_STOP(*tmul);
}
/*************************************************
* 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 c0
* - const poly *a: pointer to input polynomial
**************************************************/
void poly_power2round(poly *a1, poly *a0, const poly *a) {
unsigned int i;
DBENCH_START();
for(i = 0; i < N; ++i)
a1->coeffs[i] = power2round(&a0->coeffs[i], a->coeffs[i]);
DBENCH_STOP(*tround);
}
/*************************************************
* 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 c0
* - const poly *a: pointer to input polynomial
**************************************************/
void poly_decompose(poly *a1, poly *a0, const poly *a) {
unsigned int i;
DBENCH_START();
for(i = 0; i < N; ++i)
a1->coeffs[i] = decompose(&a0->coeffs[i], a->coeffs[i]);
DBENCH_STOP(*tround);
}
/*************************************************
* Name: poly_make_hint
*
* Description: Compute hint polynomial. The coefficients of which indicate
* whether the low bits of the corresponding coefficient of
* the input polynomial overflow into the high bits.
*
* Arguments: - poly *h: pointer to output hint polynomial
* - const poly *a0: pointer to low part of input polynomial
* - const poly *a1: pointer to high part of input polynomial
*
* Returns number of 1 bits.
**************************************************/
unsigned int poly_make_hint(poly *h, const poly *a0, const poly *a1) {
unsigned int i, s = 0;
DBENCH_START();
for(i = 0; i < N; ++i) {
h->coeffs[i] = make_hint(a0->coeffs[i], a1->coeffs[i]);
s += h->coeffs[i];
}
DBENCH_STOP(*tround);
return s;
}
/*************************************************
* Name: poly_use_hint
*
* Description: Use hint polynomial to correct the high bits of a polynomial.
*
* Arguments: - poly *b: pointer to output polynomial with corrected high bits
* - const poly *a: pointer to input polynomial
* - const poly *h: pointer to input hint polynomial
**************************************************/
void poly_use_hint(poly *b, const poly *a, const poly *h) {
unsigned int i;
DBENCH_START();
for(i = 0; i < N; ++i)
b->coeffs[i] = use_hint(a->coeffs[i], h->coeffs[i]);
DBENCH_STOP(*tround);
}
/*************************************************
* Name: poly_chknorm
*
* Description: Check infinity norm of polynomial against given bound.
* Assumes input coefficients were reduced by reduce32().
*
* Arguments: - const poly *a: pointer to polynomial
* - int32_t B: norm bound
*
* Returns 0 if norm is strictly smaller than B <= (Q-1)/8 and 1 otherwise.
**************************************************/
int poly_chknorm(const poly *a, int32_t B) {
unsigned int i;
int32_t t;
DBENCH_START();
if(B > (Q-1)/8)
return 1;
/* 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 */
t = a->coeffs[i] >> 31;
t = a->coeffs[i] - (t & 2*a->coeffs[i]);
if(t >= B) {
DBENCH_STOP(*tsample);
return 1;
}
}
DBENCH_STOP(*tsample);
return 0;
}
/*************************************************
* Name: poly_uniform
*
* Description: Sample polynomial with uniformly random coefficients
* in [0,Q-1] by performing rejection sampling on the
* output stream of SHAKE256(seed|nonce) or AES256CTR(seed,nonce).
*
* Arguments: - poly *a: pointer to output polynomial
* - const uint8_t seed[]: byte array with seed of length SEEDBYTES
* - uint16_t nonce: 2-byte nonce
**************************************************/
#define POLY_UNIFORM_NBLOCKS ((768 + STREAM128_BLOCKBYTES - 1)/STREAM128_BLOCKBYTES)
void poly_uniform(poly *a,
const uint8_t seed[SEEDBYTES],
uint16_t nonce)
{
unsigned int i, ctr, off;
unsigned int buflen = POLY_UNIFORM_NBLOCKS*STREAM128_BLOCKBYTES;
uint8_t buf[POLY_UNIFORM_NBLOCKS*STREAM128_BLOCKBYTES + 2];
stream128_state state;
stream128_init(&state, seed, nonce);
stream128_squeezeblocks(buf, POLY_UNIFORM_NBLOCKS, &state);
ctr = asm_rej_uniform(a->coeffs, N, buf, buflen);
while(ctr < N) {
off = buflen % 3;
for(i = 0; i < off; ++i)
buf[i] = buf[buflen - off + i];
stream128_squeezeblocks(buf + off, 1, &state);
buflen = STREAM128_BLOCKBYTES + off;
ctr += asm_rej_uniform(a->coeffs + ctr, N - ctr, buf, buflen);
}
}
/*************************************************
* Name: rej_eta
*
* Description: Sample uniformly random coefficients in [-ETA, ETA] by
* performing rejection sampling on array of random bytes.
*
* Arguments: - int32_t *a: pointer to output array (allocated)
* - unsigned int len: number of coefficients to be sampled
* - const uint8_t *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(int32_t *a,
unsigned int len,
const uint8_t *buf,
unsigned int buflen)
{
unsigned int ctr, pos;
uint32_t t0, t1;
DBENCH_START();
ctr = pos = 0;
while(ctr < len && pos < buflen) {
t0 = buf[pos] & 0x0F;
t1 = buf[pos++] >> 4;
#if ETA == 2
if(t0 < 15) {
t0 = t0 - (205*t0 >> 10)*5;
a[ctr++] = 2 - t0;
}
if(t1 < 15 && ctr < len) {
t1 = t1 - (205*t1 >> 10)*5;
a[ctr++] = 2 - t1;
}
#elif ETA == 4
if(t0 < 9)
a[ctr++] = 4 - t0;
if(t1 < 9 && ctr < len)
a[ctr++] = 4 - t1;
#endif
}
DBENCH_STOP(*tsample);
return ctr;
}
/*************************************************
* Name: poly_uniform_eta
*
* Description: Sample polynomial with uniformly random coefficients
* in [-ETA,ETA] by performing rejection sampling on the
* output stream from SHAKE256(seed|nonce) or AES256CTR(seed,nonce).
*
* Arguments: - poly *a: pointer to output polynomial
* - const uint8_t seed[]: byte array with seed of length SEEDBYTES
* - uint16_t nonce: 2-byte nonce
**************************************************/
#if ETA == 2
#define POLY_UNIFORM_ETA_NBLOCKS ((136 + STREAM256_BLOCKBYTES - 1)/STREAM256_BLOCKBYTES)
#elif ETA == 4
#define POLY_UNIFORM_ETA_NBLOCKS ((227 + STREAM256_BLOCKBYTES - 1)/STREAM256_BLOCKBYTES)
#endif
void poly_uniform_eta(poly *a,
const uint8_t seed[CRHBYTES],
uint16_t nonce) {
unsigned int ctr;
unsigned int buflen = POLY_UNIFORM_ETA_NBLOCKS * STREAM256_BLOCKBYTES;
uint8_t buf[POLY_UNIFORM_ETA_NBLOCKS * STREAM256_BLOCKBYTES];
stream256_state state;
stream256_init(&state, seed, nonce);
stream256_squeezeblocks(buf, POLY_UNIFORM_ETA_NBLOCKS, &state);
ctr = rej_eta(a->coeffs, N, buf, buflen);
while(ctr < N) {
stream256_squeezeblocks(buf, 1, &state);
ctr += rej_eta(a->coeffs + ctr, N - ctr, buf, STREAM256_BLOCKBYTES);
}
}
/*************************************************
* Name: poly_uniform_gamma1m1
*
* Description: Sample polynomial with uniformly random coefficients
* in [-(GAMMA1 - 1), GAMMA1] by unpacking output stream
* of SHAKE256(seed|nonce) or AES256CTR(seed,nonce).
*
* Arguments: - poly *a: pointer to output polynomial
* - const uint8_t seed[]: byte array with seed of length CRHBYTES
* - uint16_t nonce: 16-bit nonce
**************************************************/
#define POLY_UNIFORM_GAMMA1_NBLOCKS ((POLYZ_PACKEDBYTES + STREAM256_BLOCKBYTES - 1)/STREAM256_BLOCKBYTES)
void poly_uniform_gamma1(poly *a,
const uint8_t seed[CRHBYTES],
uint16_t nonce)
{
uint8_t buf[POLY_UNIFORM_GAMMA1_NBLOCKS*STREAM256_BLOCKBYTES];
stream256_state state;
stream256_init(&state, seed, nonce);
stream256_squeezeblocks(buf, POLY_UNIFORM_GAMMA1_NBLOCKS, &state);
polyz_unpack(a, buf);
}
/*************************************************
* Name: challenge
*
* Description: Implementation of H. Samples polynomial with TAU nonzero
* coefficients in {-1,1} using the output stream of
* SHAKE256(seed).
*
* Arguments: - poly *c: pointer to output polynomial
* - const uint8_t mu[]: byte array containing seed of length SEEDBYTES
**************************************************/
void poly_challenge(poly *c, const uint8_t seed[SEEDBYTES]) {
unsigned int i, b, pos;
uint64_t signs;
uint8_t buf[SHAKE256_RATE];
shake256incctx state;
shake256_inc_init(&state);
shake256_inc_absorb(&state, seed, SEEDBYTES);
shake256_inc_finalize(&state);
shake256_inc_squeezeblocks(buf, 1, &state);
signs = 0;
for(i = 0; i < 8; ++i)
signs |= (uint64_t)buf[i] << 8*i;
pos = 8;
for(i = 0; i < N; ++i)
c->coeffs[i] = 0;
for(i = N-TAU; i < N; ++i) {
do {
if(pos >= SHAKE256_RATE) {
shake256_inc_squeezeblocks(buf, 1, &state);
pos = 0;
}
b = buf[pos++];
} while(b > i);
c->coeffs[i] = c->coeffs[b];
c->coeffs[b] = 1 - 2*(signs & 1);
signs >>= 1;
}
}
/*************************************************
* Name: polyeta_pack
*
* Description: Bit-pack polynomial with coefficients in [-ETA,ETA].
*
* Arguments: - uint8_t *r: pointer to output byte array with at least
* POLYETA_PACKEDBYTES bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void polyeta_pack(uint8_t *r, const poly *a) {
unsigned int i;
uint8_t t[8];
DBENCH_START();
#if ETA == 2
for(i = 0; i < N/8; ++i) {
t[0] = ETA - a->coeffs[8*i+0];
t[1] = ETA - a->coeffs[8*i+1];
t[2] = ETA - a->coeffs[8*i+2];
t[3] = ETA - a->coeffs[8*i+3];
t[4] = ETA - a->coeffs[8*i+4];
t[5] = ETA - a->coeffs[8*i+5];
t[6] = ETA - a->coeffs[8*i+6];
t[7] = ETA - a->coeffs[8*i+7];
r[3*i+0] = (t[0] >> 0) | (t[1] << 3) | (t[2] << 6);
r[3*i+1] = (t[2] >> 2) | (t[3] << 1) | (t[4] << 4) | (t[5] << 7);
r[3*i+2] = (t[5] >> 1) | (t[6] << 2) | (t[7] << 5);
}
#elif ETA == 4
for(i = 0; i < N/2; ++i) {
t[0] = ETA - a->coeffs[2*i+0];
t[1] = ETA - a->coeffs[2*i+1];
r[i] = t[0] | (t[1] << 4);
}
#endif
DBENCH_STOP(*tpack);
}
/*************************************************
* Name: polyt1_pack
*
* Description: Bit-pack polynomial t1 with coefficients fitting in 10 bits.
* Input coefficients are assumed to be standard representatives.
*
* Arguments: - uint8_t *r: pointer to output byte array with at least
* POLYT1_PACKEDBYTES bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void polyt1_pack(uint8_t *r, const poly *a) {
unsigned int i;
DBENCH_START();
for(i = 0; i < N/4; ++i) {
r[5*i+0] = (a->coeffs[4*i+0] >> 0);
r[5*i+1] = (a->coeffs[4*i+0] >> 8) | (a->coeffs[4*i+1] << 2);
r[5*i+2] = (a->coeffs[4*i+1] >> 6) | (a->coeffs[4*i+2] << 4);
r[5*i+3] = (a->coeffs[4*i+2] >> 4) | (a->coeffs[4*i+3] << 6);
r[5*i+4] = (a->coeffs[4*i+3] >> 2);
}
DBENCH_STOP(*tpack);
}
/*************************************************
* Name: polyt1_unpack
*
* Description: Unpack polynomial t1 with 10-bit coefficients.
* Output coefficients are standard representatives.
*
* Arguments: - poly *r: pointer to output polynomial
* - const uint8_t *a: byte array with bit-packed polynomial
**************************************************/
void polyt1_unpack(poly *r, const uint8_t *a) {
unsigned int i;
DBENCH_START();
for(i = 0; i < N/4; ++i) {
r->coeffs[4*i+0] = ((a[5*i+0] >> 0) | ((uint32_t)a[5*i+1] << 8)) & 0x3FF;
r->coeffs[4*i+1] = ((a[5*i+1] >> 2) | ((uint32_t)a[5*i+2] << 6)) & 0x3FF;
r->coeffs[4*i+2] = ((a[5*i+2] >> 4) | ((uint32_t)a[5*i+3] << 4)) & 0x3FF;
r->coeffs[4*i+3] = ((a[5*i+3] >> 6) | ((uint32_t)a[5*i+4] << 2)) & 0x3FF;
}
DBENCH_STOP(*tpack);
}
/*************************************************
* Name: polyt0_pack
*
* Description: Bit-pack polynomial t0 with coefficients in ]-2^{D-1}, 2^{D-1}].
*
* Arguments: - uint8_t *r: pointer to output byte array with at least
* POLYT0_PACKEDBYTES bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void polyt0_pack(uint8_t *r, const poly *a) {
unsigned int i;
uint32_t t[8];
DBENCH_START();
for(i = 0; i < N/8; ++i) {
t[0] = (1 << (D-1)) - a->coeffs[8*i+0];
t[1] = (1 << (D-1)) - a->coeffs[8*i+1];
t[2] = (1 << (D-1)) - a->coeffs[8*i+2];
t[3] = (1 << (D-1)) - a->coeffs[8*i+3];
t[4] = (1 << (D-1)) - a->coeffs[8*i+4];
t[5] = (1 << (D-1)) - a->coeffs[8*i+5];
t[6] = (1 << (D-1)) - a->coeffs[8*i+6];
t[7] = (1 << (D-1)) - a->coeffs[8*i+7];
r[13*i+ 0] = t[0];
r[13*i+ 1] = t[0] >> 8;
r[13*i+ 1] |= t[1] << 5;
r[13*i+ 2] = t[1] >> 3;
r[13*i+ 3] = t[1] >> 11;
r[13*i+ 3] |= t[2] << 2;
r[13*i+ 4] = t[2] >> 6;
r[13*i+ 4] |= t[3] << 7;
r[13*i+ 5] = t[3] >> 1;
r[13*i+ 6] = t[3] >> 9;
r[13*i+ 6] |= t[4] << 4;
r[13*i+ 7] = t[4] >> 4;
r[13*i+ 8] = t[4] >> 12;
r[13*i+ 8] |= t[5] << 1;
r[13*i+ 9] = t[5] >> 7;
r[13*i+ 9] |= t[6] << 6;
r[13*i+10] = t[6] >> 2;
r[13*i+11] = t[6] >> 10;
r[13*i+11] |= t[7] << 3;
r[13*i+12] = t[7] >> 5;
}
DBENCH_STOP(*tpack);
}
/*************************************************
* Name: polyt0_unpack
*
* Description: Unpack polynomial t0 with coefficients in ]-2^{D-1}, 2^{D-1}].
*
* Arguments: - poly *r: pointer to output polynomial
* - const uint8_t *a: byte array with bit-packed polynomial
**************************************************/
void polyt0_unpack(poly *r, const uint8_t *a) {
unsigned int i;
DBENCH_START();
for(i = 0; i < N/8; ++i) {
r->coeffs[8*i+0] = a[13*i+0];
r->coeffs[8*i+0] |= (uint32_t)a[13*i+1] << 8;
r->coeffs[8*i+0] &= 0x1FFF;
r->coeffs[8*i+1] = a[13*i+1] >> 5;
r->coeffs[8*i+1] |= (uint32_t)a[13*i+2] << 3;
r->coeffs[8*i+1] |= (uint32_t)a[13*i+3] << 11;
r->coeffs[8*i+1] &= 0x1FFF;
r->coeffs[8*i+2] = a[13*i+3] >> 2;
r->coeffs[8*i+2] |= (uint32_t)a[13*i+4] << 6;
r->coeffs[8*i+2] &= 0x1FFF;
r->coeffs[8*i+3] = a[13*i+4] >> 7;
r->coeffs[8*i+3] |= (uint32_t)a[13*i+5] << 1;
r->coeffs[8*i+3] |= (uint32_t)a[13*i+6] << 9;
r->coeffs[8*i+3] &= 0x1FFF;
r->coeffs[8*i+4] = a[13*i+6] >> 4;
r->coeffs[8*i+4] |= (uint32_t)a[13*i+7] << 4;
r->coeffs[8*i+4] |= (uint32_t)a[13*i+8] << 12;
r->coeffs[8*i+4] &= 0x1FFF;
r->coeffs[8*i+5] = a[13*i+8] >> 1;
r->coeffs[8*i+5] |= (uint32_t)a[13*i+9] << 7;
r->coeffs[8*i+5] &= 0x1FFF;
r->coeffs[8*i+6] = a[13*i+9] >> 6;
r->coeffs[8*i+6] |= (uint32_t)a[13*i+10] << 2;
r->coeffs[8*i+6] |= (uint32_t)a[13*i+11] << 10;
r->coeffs[8*i+6] &= 0x1FFF;
r->coeffs[8*i+7] = a[13*i+11] >> 3;
r->coeffs[8*i+7] |= (uint32_t)a[13*i+12] << 5;
r->coeffs[8*i+7] &= 0x1FFF;
r->coeffs[8*i+0] = (1 << (D-1)) - r->coeffs[8*i+0];
r->coeffs[8*i+1] = (1 << (D-1)) - r->coeffs[8*i+1];
r->coeffs[8*i+2] = (1 << (D-1)) - r->coeffs[8*i+2];
r->coeffs[8*i+3] = (1 << (D-1)) - r->coeffs[8*i+3];
r->coeffs[8*i+4] = (1 << (D-1)) - r->coeffs[8*i+4];
r->coeffs[8*i+5] = (1 << (D-1)) - r->coeffs[8*i+5];
r->coeffs[8*i+6] = (1 << (D-1)) - r->coeffs[8*i+6];
r->coeffs[8*i+7] = (1 << (D-1)) - r->coeffs[8*i+7];
}
DBENCH_STOP(*tpack);
}
/*************************************************
* Name: polyz_pack
*
* Description: Bit-pack polynomial with coefficients
* in [-(GAMMA1 - 1), GAMMA1].
*
* Arguments: - uint8_t *r: pointer to output byte array with at least
* POLYZ_PACKEDBYTES bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void polyz_pack(uint8_t *r, const poly *a) {
unsigned int i;
uint32_t t[4];
DBENCH_START();
#if GAMMA1 == (1 << 17)
for(i = 0; i < N/4; ++i) {
t[0] = GAMMA1 - a->coeffs[4*i+0];
t[1] = GAMMA1 - a->coeffs[4*i+1];
t[2] = GAMMA1 - a->coeffs[4*i+2];
t[3] = GAMMA1 - a->coeffs[4*i+3];
r[9*i+0] = t[0];
r[9*i+1] = t[0] >> 8;
r[9*i+2] = t[0] >> 16;
r[9*i+2] |= t[1] << 2;
r[9*i+3] = t[1] >> 6;
r[9*i+4] = t[1] >> 14;
r[9*i+4] |= t[2] << 4;
r[9*i+5] = t[2] >> 4;
r[9*i+6] = t[2] >> 12;
r[9*i+6] |= t[3] << 6;
r[9*i+7] = t[3] >> 2;
r[9*i+8] = t[3] >> 10;
}
#elif GAMMA1 == (1 << 19)
for(i = 0; i < N/2; ++i) {
t[0] = GAMMA1 - a->coeffs[2*i+0];
t[1] = GAMMA1 - a->coeffs[2*i+1];
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;
}
#endif
DBENCH_STOP(*tpack);
}
/*************************************************
* Name: polyz_unpack
*
* Description: Unpack polynomial z with coefficients
* in [-(GAMMA1 - 1), GAMMA1].
*
* Arguments: - poly *r: pointer to output polynomial
* - const uint8_t *a: byte array with bit-packed polynomial
**************************************************/
void polyz_unpack(poly *r, const uint8_t *a) {
unsigned int i;
DBENCH_START();
#if GAMMA1 == (1 << 17)
for(i = 0; i < N/4; ++i) {
r->coeffs[4*i+0] = a[9*i+0];
r->coeffs[4*i+0] |= (uint32_t)a[9*i+1] << 8;
r->coeffs[4*i+0] |= (uint32_t)a[9*i+2] << 16;
r->coeffs[4*i+0] &= 0x3FFFF;
r->coeffs[4*i+1] = a[9*i+2] >> 2;
r->coeffs[4*i+1] |= (uint32_t)a[9*i+3] << 6;
r->coeffs[4*i+1] |= (uint32_t)a[9*i+4] << 14;
r->coeffs[4*i+1] &= 0x3FFFF;
r->coeffs[4*i+2] = a[9*i+4] >> 4;
r->coeffs[4*i+2] |= (uint32_t)a[9*i+5] << 4;
r->coeffs[4*i+2] |= (uint32_t)a[9*i+6] << 12;
r->coeffs[4*i+2] &= 0x3FFFF;
r->coeffs[4*i+3] = a[9*i+6] >> 6;
r->coeffs[4*i+3] |= (uint32_t)a[9*i+7] << 2;
r->coeffs[4*i+3] |= (uint32_t)a[9*i+8] << 10;
r->coeffs[4*i+3] &= 0x3FFFF;
r->coeffs[4*i+0] = GAMMA1 - r->coeffs[4*i+0];
r->coeffs[4*i+1] = GAMMA1 - r->coeffs[4*i+1];
r->coeffs[4*i+2] = GAMMA1 - r->coeffs[4*i+2];
r->coeffs[4*i+3] = GAMMA1 - r->coeffs[4*i+3];
}
#elif GAMMA1 == (1 << 19)
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] << 16;
r->coeffs[2*i+0] &= 0xFFFFF;
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] &= 0xFFFFF;
r->coeffs[2*i+0] = GAMMA1 - r->coeffs[2*i+0];
r->coeffs[2*i+1] = GAMMA1 - r->coeffs[2*i+1];
}
#endif
DBENCH_STOP(*tpack);
}
/*************************************************
* Name: polyw1_pack
*
* Description: Bit-pack polynomial w1 with coefficients in [0,15] or [0,43].
* Input coefficients are assumed to be standard representatives.
*
* Arguments: - uint8_t *r: pointer to output byte array with at least
* POLYW1_PACKEDBYTES bytes
* - const poly *a: pointer to input polynomial
**************************************************/
void polyw1_pack(uint8_t *r, const poly *a) {
unsigned int i;
DBENCH_START();
#if GAMMA2 == (Q-1)/88
for(i = 0; i < N/4; ++i) {
r[3*i+0] = a->coeffs[4*i+0];
r[3*i+0] |= a->coeffs[4*i+1] << 6;
r[3*i+1] = a->coeffs[4*i+1] >> 2;
r[3*i+1] |= a->coeffs[4*i+2] << 4;
r[3*i+2] = a->coeffs[4*i+2] >> 4;
r[3*i+2] |= a->coeffs[4*i+3] << 2;
}
#elif GAMMA2 == (Q-1)/32
for(i = 0; i < N/2; ++i)
r[i] = a->coeffs[2*i+0] | (a->coeffs[2*i+1] << 4);
#endif
DBENCH_STOP(*tpack);
}
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