pqcrypto/crypto_sign/dilithium-iii/clean/polyvec.c

#include "polyvec.h"
#include "params.h"
#include "poly.h"
#include <stdint.h>

/**************************************************************/
/************ Vectors of polynomials of length L **************/
/**************************************************************/

/*************************************************
 * Name:        polyvecl_freeze
 *
 * Description: Reduce coefficients of polynomials in vector of length L
 *              to standard representatives.
 *
 * Arguments:   - polyvecl *v: pointer to input/output vector
 **************************************************/
void polyvecl_freeze(polyvecl *v) {
  unsigned int i;

  for (i = 0; i < L; ++i)
    poly_freeze(v->vec + i);
}

/*************************************************
 * Name:        polyvecl_add
 *
 * Description: Add vectors of polynomials of length L.
 *              No modular reduction is performed.
 *
 * Arguments:   - polyvecl *w: pointer to output vector
 *              - const polyvecl *u: pointer to first summand
 *              - const polyvecl *v: pointer to second summand
 **************************************************/
void polyvecl_add(polyvecl *w, const polyvecl *u, const polyvecl *v) {
  unsigned int i;

  for (i = 0; i < L; ++i)
    poly_add(w->vec + i, u->vec + i, v->vec + i);
}

/*************************************************
 * Name:        polyvecl_ntt
 *
 * Description: Forward NTT of all polynomials in vector of length L. Output
 *              coefficients can be up to 16*Q larger than input coefficients.
 *
 * Arguments:   - polyvecl *v: pointer to input/output vector
 **************************************************/
void polyvecl_ntt(polyvecl *v) {
  unsigned int i;

  for (i = 0; i < L; ++i)
    poly_ntt(v->vec + i);
}

/*************************************************
 * Name:        polyvecl_pointwise_acc_invmontgomery
 *
 * Description: Pointwise multiply vectors of polynomials of length L, multiply
 *              resulting vector by 2^{-32} and add (accumulate) polynomials
 *              in it. Input/output vectors are in NTT domain representation.
 *              Input coefficients are assumed to be less than 22*Q. Output
 *              coeffcient are less than 2*L*Q.
 *
 * Arguments:   - poly *w: output polynomial
 *              - const polyvecl *u: pointer to first input vector
 *              - const polyvecl *v: pointer to second input vector
 **************************************************/
void polyvecl_pointwise_acc_invmontgomery(poly *w, const polyvecl *u,
                                          const polyvecl *v) {
  unsigned int i;
  poly t;

  poly_pointwise_invmontgomery(w, u->vec + 0, v->vec + 0);

  for (i = 1; i < L; ++i) {
    poly_pointwise_invmontgomery(&t, u->vec + i, v->vec + i);
    poly_add(w, w, &t);
  }
}

/*************************************************
 * Name:        polyvecl_chknorm
 *
 * Description: Check infinity norm of polynomials in vector of length L.
 *              Assumes input coefficients to be standard representatives.
 *
 * Arguments:   - const polyvecl *v: pointer to vector
 *              - uint32_t B: norm bound
 *
 * Returns 0 if norm of all polynomials is strictly smaller than B and 1
 * otherwise.
 **************************************************/
int polyvecl_chknorm(const polyvecl *v, uint32_t bound) {
  unsigned int i;
  int ret = 0;

  for (i = 0; i < L; ++i)
    ret |= poly_chknorm(v->vec + i, bound);

  return ret;
}

/**************************************************************/
/************ Vectors of polynomials of length K **************/
/**************************************************************/

/*************************************************
 * Name:        polyveck_reduce
 *
 * Description: Reduce coefficients of polynomials in vector of length K
 *              to representatives in [0,2*Q[.
 *
 * Arguments:   - polyveck *v: pointer to input/output vector
 **************************************************/
void polyveck_reduce(polyveck *v) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_reduce(v->vec + i);
}

/*************************************************
 * Name:        polyveck_csubq
 *
 * Description: For all coefficients of polynomials in vector of length K
 *              subtract Q if coefficient is bigger than Q.
 *
 * Arguments:   - polyveck *v: pointer to input/output vector
 **************************************************/
void polyveck_csubq(polyveck *v) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_csubq(v->vec + i);
}

/*************************************************
 * Name:        polyveck_freeze
 *
 * Description: Reduce coefficients of polynomials in vector of length K
 *              to standard representatives.
 *
 * Arguments:   - polyveck *v: pointer to input/output vector
 **************************************************/
void polyveck_freeze(polyveck *v) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_freeze(v->vec + i);
}

/*************************************************
 * Name:        polyveck_add
 *
 * Description: Add vectors of polynomials of length K.
 *              No modular reduction is performed.
 *
 * Arguments:   - polyveck *w: pointer to output vector
 *              - const polyveck *u: pointer to first summand
 *              - const polyveck *v: pointer to second summand
 **************************************************/
void polyveck_add(polyveck *w, const polyveck *u, const polyveck *v) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_add(w->vec + i, u->vec + i, v->vec + i);
}

/*************************************************
 * Name:        polyveck_sub
 *
 * Description: Subtract vectors of polynomials of length K.
 *              Assumes coefficients of polynomials in second input vector
 *              to be less than 2*Q. No modular reduction is performed.
 *
 * Arguments:   - polyveck *w: pointer to output vector
 *              - const polyveck *u: pointer to first input vector
 *              - const polyveck *v: pointer to second input vector to be
 *                                   subtracted from first input vector
 **************************************************/
void polyveck_sub(polyveck *w, const polyveck *u, const polyveck *v) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_sub(w->vec + i, u->vec + i, v->vec + i);
}

/*************************************************
 * Name:        polyveck_shiftl
 *
 * Description: Multiply vector of polynomials of Length K by 2^k without
 *modular reduction. Assumes input coefficients to be less than 2^{32-k}.
 *
 * Arguments:   - polyveck *v: pointer to input/output vector
 *              - unsigned int k: exponent
 **************************************************/
void polyveck_shiftl(polyveck *v, unsigned int k) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_shiftl(v->vec + i, k);
}

/*************************************************
 * Name:        polyveck_ntt
 *
 * Description: Forward NTT of all polynomials in vector of length K. Output
 *              coefficients can be up to 16*Q larger than input coefficients.
 *
 * Arguments:   - polyveck *v: pointer to input/output vector
 **************************************************/
void polyveck_ntt(polyveck *v) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_ntt(v->vec + i);
}

/*************************************************
 * Name:        polyveck_invntt_montgomery
 *
 * Description: Inverse NTT and multiplication by 2^{32} of polynomials
 *              in vector of length K. Input coefficients need to be less
 *              than 2*Q.
 *
 * Arguments:   - polyveck *v: pointer to input/output vector
 **************************************************/
void polyveck_invntt_montgomery(polyveck *v) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_invntt_montgomery(v->vec + i);
}

/*************************************************
 * Name:        polyveck_chknorm
 *
 * Description: Check infinity norm of polynomials in vector of length K.
 *              Assumes input coefficients to be standard representatives.
 *
 * Arguments:   - const polyveck *v: pointer to vector
 *              - uint32_t B: norm bound
 *
 * Returns 0 if norm of all polynomials are strictly smaller than B and 1
 * otherwise.
 **************************************************/
int polyveck_chknorm(const polyveck *v, uint32_t bound) {
  unsigned int i;
  int ret = 0;

  for (i = 0; i < K; ++i)
    ret |= poly_chknorm(v->vec + i, bound);

  return ret;
}

/*************************************************
 * Name:        polyveck_power2round
 *
 * Description: For all coefficients a of polynomials in vector of length K,
 *              compute a0, a1 such that a mod Q = a1*2^D + a0
 *              with -2^{D-1} < a0 <= 2^{D-1}. Assumes coefficients to be
 *              standard representatives.
 *
 * Arguments:   - polyveck *v1: pointer to output vector of polynomials with
 *                              coefficients a1
 *              - polyveck *v0: pointer to output vector of polynomials with
 *                              coefficients Q + a0
 *              - const polyveck *v: pointer to input vector
 **************************************************/
void polyveck_power2round(polyveck *v1, polyveck *v0, const polyveck *v) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_power2round(v1->vec + i, v0->vec + i, v->vec + i);
}

/*************************************************
 * Name:        polyveck_decompose
 *
 * Description: For all coefficients a of polynomials in vector of length K,
 *              compute high and low bits a0, a1 such a mod Q = a1*ALPHA + a0
 *              with -ALPHA/2 < a0 <= ALPHA/2 except a1 = (Q-1)/ALPHA where we
 *              set a1 = 0 and -ALPHA/2 <= a0 = a mod Q - Q < 0.
 *              Assumes coefficients to be standard representatives.
 *
 * Arguments:   - polyveck *v1: pointer to output vector of polynomials with
 *                              coefficients a1
 *              - polyveck *v0: pointer to output vector of polynomials with
 *                              coefficients Q + a0
 *              - const polyveck *v: pointer to input vector
 **************************************************/
void polyveck_decompose(polyveck *v1, polyveck *v0, const polyveck *v) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_decompose(v1->vec + i, v0->vec + i, v->vec + i);
}

/*************************************************
 * Name:        polyveck_make_hint
 *
 * Description: Compute hint vector.
 *
 * Arguments:   - polyveck *h: pointer to output vector
 *              - const polyveck *u: pointer to first input vector
 *              - const polyveck *u: pointer to second input vector
 *
 * Returns number of 1 bits.
 **************************************************/
unsigned int polyveck_make_hint(polyveck *h, const polyveck *u,
                                const polyveck *v) {
  unsigned int i, s = 0;

  for (i = 0; i < K; ++i)
    s += poly_make_hint(h->vec + i, u->vec + i, v->vec + i);

  return s;
}

/*************************************************
 * Name:        polyveck_use_hint
 *
 * Description: Use hint vector to correct the high bits of input vector.
 *
 * Arguments:   - polyveck *w: pointer to output vector of polynomials with
 *                             corrected high bits
 *              - const polyveck *u: pointer to input vector
 *              - const polyveck *h: pointer to input hint vector
 **************************************************/
void polyveck_use_hint(polyveck *w, const polyveck *u, const polyveck *h) {
  unsigned int i;

  for (i = 0; i < K; ++i)
    poly_use_hint(w->vec + i, u->vec + i, h->vec + i);
}