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#include <stdint.h>
#include "params.h"
#include "poly.h"
#include "polyvec.h"
/*************************************************
* Name: polyvec_compress
*
* Description: Compress and serialize vector of polynomials
*
* Arguments: - uint8_t *r: pointer to output byte array
* (needs space for KYBER_POLYVECCOMPRESSEDBYTES)
* - const polyvec *a: pointer to input vector of polynomials
**************************************************/
void polyvec_compress(uint8_t r[KYBER_POLYVECCOMPRESSEDBYTES], const polyvec *a)
{
unsigned int i,j,k;
#if (KYBER_POLYVECCOMPRESSEDBYTES == (KYBER_K * 352))
uint16_t t[8];
for(i=0;i<KYBER_K;i++) {
for(j=0;j<KYBER_N/8;j++) {
for(k=0;k<8;k++) {
t[k] = a->vec[i].coeffs[8*j+k];
t[k] += ((int16_t)t[k] >> 15) & KYBER_Q;
t[k] = ((((uint32_t)t[k] << 11) + KYBER_Q/2)/KYBER_Q) & 0x7ff;
}
r[ 0] = (t[0] >> 0);
r[ 1] = (t[0] >> 8) | (t[1] << 3);
r[ 2] = (t[1] >> 5) | (t[2] << 6);
r[ 3] = (t[2] >> 2);
r[ 4] = (t[2] >> 10) | (t[3] << 1);
r[ 5] = (t[3] >> 7) | (t[4] << 4);
r[ 6] = (t[4] >> 4) | (t[5] << 7);
r[ 7] = (t[5] >> 1);
r[ 8] = (t[5] >> 9) | (t[6] << 2);
r[ 9] = (t[6] >> 6) | (t[7] << 5);
r[10] = (t[7] >> 3);
r += 11;
}
}
#elif (KYBER_POLYVECCOMPRESSEDBYTES == (KYBER_K * 320))
uint16_t t[4];
for(i=0;i<KYBER_K;i++) {
for(j=0;j<KYBER_N/4;j++) {
for(k=0;k<4;k++) {
t[k] = a->vec[i].coeffs[4*j+k];
t[k] += ((int16_t)t[k] >> 15) & KYBER_Q;
t[k] = ((((uint32_t)t[k] << 10) + KYBER_Q/2)/ KYBER_Q) & 0x3ff;
}
r[0] = (t[0] >> 0);
r[1] = (t[0] >> 8) | (t[1] << 2);
r[2] = (t[1] >> 6) | (t[2] << 4);
r[3] = (t[2] >> 4) | (t[3] << 6);
r[4] = (t[3] >> 2);
r += 5;
}
}
#else
#error "KYBER_POLYVECCOMPRESSEDBYTES needs to be in {320*KYBER_K, 352*KYBER_K}"
#endif
}
/*************************************************
* Name: polyvec_decompress
*
* Description: De-serialize and decompress vector of polynomials;
* approximate inverse of polyvec_compress
*
* Arguments: - polyvec *r: pointer to output vector of polynomials
* - const uint8_t *a: pointer to input byte array
* (of length KYBER_POLYVECCOMPRESSEDBYTES)
**************************************************/
void polyvec_decompress(polyvec *r, const uint8_t a[KYBER_POLYVECCOMPRESSEDBYTES])
{
unsigned int i,j,k;
#if (KYBER_POLYVECCOMPRESSEDBYTES == (KYBER_K * 352))
uint16_t t[8];
for(i=0;i<KYBER_K;i++) {
for(j=0;j<KYBER_N/8;j++) {
t[0] = (a[0] >> 0) | ((uint16_t)a[ 1] << 8);
t[1] = (a[1] >> 3) | ((uint16_t)a[ 2] << 5);
t[2] = (a[2] >> 6) | ((uint16_t)a[ 3] << 2) | ((uint16_t)a[4] << 10);
t[3] = (a[4] >> 1) | ((uint16_t)a[ 5] << 7);
t[4] = (a[5] >> 4) | ((uint16_t)a[ 6] << 4);
t[5] = (a[6] >> 7) | ((uint16_t)a[ 7] << 1) | ((uint16_t)a[8] << 9);
t[6] = (a[8] >> 2) | ((uint16_t)a[ 9] << 6);
t[7] = (a[9] >> 5) | ((uint16_t)a[10] << 3);
a += 11;
for(k=0;k<8;k++)
r->vec[i].coeffs[8*j+k] = ((uint32_t)(t[k] & 0x7FF)*KYBER_Q + 1024) >> 11;
}
}
#elif (KYBER_POLYVECCOMPRESSEDBYTES == (KYBER_K * 320))
uint16_t t[4];
for(i=0;i<KYBER_K;i++) {
for(j=0;j<KYBER_N/4;j++) {
t[0] = (a[0] >> 0) | ((uint16_t)a[1] << 8);
t[1] = (a[1] >> 2) | ((uint16_t)a[2] << 6);
t[2] = (a[2] >> 4) | ((uint16_t)a[3] << 4);
t[3] = (a[3] >> 6) | ((uint16_t)a[4] << 2);
a += 5;
for(k=0;k<4;k++)
r->vec[i].coeffs[4*j+k] = ((uint32_t)(t[k] & 0x3FF)*KYBER_Q + 512) >> 10;
}
}
#else
#error "KYBER_POLYVECCOMPRESSEDBYTES needs to be in {320*KYBER_K, 352*KYBER_K}"
#endif
}
/*************************************************
* Name: polyvec_tobytes
*
* Description: Serialize vector of polynomials
*
* Arguments: - uint8_t *r: pointer to output byte array
* (needs space for KYBER_POLYVECBYTES)
* - const polyvec *a: pointer to input vector of polynomials
**************************************************/
void polyvec_tobytes(uint8_t r[KYBER_POLYVECBYTES], const polyvec *a)
{
unsigned int i;
for(i=0;i<KYBER_K;i++)
poly_tobytes(r+i*KYBER_POLYBYTES, &a->vec[i]);
}
/*************************************************
* Name: polyvec_frombytes
*
* Description: De-serialize vector of polynomials;
* inverse of polyvec_tobytes
*
* Arguments: - uint8_t *r: pointer to output byte array
* - const polyvec *a: pointer to input vector of polynomials
* (of length KYBER_POLYVECBYTES)
**************************************************/
void polyvec_frombytes(polyvec *r, const uint8_t a[KYBER_POLYVECBYTES])
{
unsigned int i;
for(i=0;i<KYBER_K;i++)
poly_frombytes(&r->vec[i], a+i*KYBER_POLYBYTES);
}
/*************************************************
* Name: polyvec_ntt
*
* Description: Apply forward NTT to all elements of a vector of polynomials
*
* Arguments: - polyvec *r: pointer to in/output vector of polynomials
**************************************************/
void polyvec_ntt(polyvec *r)
{
unsigned int i;
for(i=0;i<KYBER_K;i++)
poly_ntt(&r->vec[i]);
}
/*************************************************
* Name: polyvec_invntt_tomont
*
* Description: Apply inverse NTT to all elements of a vector of polynomials
* and multiply by Montgomery factor 2^16
*
* Arguments: - polyvec *r: pointer to in/output vector of polynomials
**************************************************/
void polyvec_invntt_tomont(polyvec *r)
{
unsigned int i;
for(i=0;i<KYBER_K;i++)
poly_invntt_tomont(&r->vec[i]);
}
/*************************************************
* Name: polyvec_basemul_acc_montgomery
*
* Description: Multiply elements of a and b in NTT domain, accumulate into r,
* and multiply by 2^-16.
*
* Arguments: - poly *r: pointer to output polynomial
* - const polyvec *a: pointer to first input vector of polynomials
* - const polyvec *b: pointer to second input vector of polynomials
**************************************************/
void polyvec_basemul_acc_montgomery(poly *r, const polyvec *a, const polyvec *b)
{
unsigned int i;
poly t;
poly_basemul_montgomery(r, &a->vec[0], &b->vec[0]);
for(i=1;i<KYBER_K;i++) {
poly_basemul_montgomery(&t, &a->vec[i], &b->vec[i]);
poly_add(r, r, &t);
}
poly_reduce(r);
}
/*************************************************
* Name: polyvec_reduce
*
* Description: Applies Barrett reduction to each coefficient
* of each element of a vector of polynomials;
* for details of the Barrett reduction see comments in reduce.c
*
* Arguments: - polyvec *r: pointer to input/output polynomial
**************************************************/
void polyvec_reduce(polyvec *r)
{
unsigned int i;
for(i=0;i<KYBER_K;i++)
poly_reduce(&r->vec[i]);
}
/*************************************************
* Name: polyvec_add
*
* Description: Add vectors of polynomials
*
* Arguments: - polyvec *r: pointer to output vector of polynomials
* - const polyvec *a: pointer to first input vector of polynomials
* - const polyvec *b: pointer to second input vector of polynomials
**************************************************/
void polyvec_add(polyvec *r, const polyvec *a, const polyvec *b)
{
unsigned int i;
for(i=0;i<KYBER_K;i++)
poly_add(&r->vec[i], &a->vec[i], &b->vec[i]);
}
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