-rw-r--r-- 6390 libmceliece-20240513/crypto_kem/8192128f/vec/pk_gen.c raw
/*
This file is for public-key generation
*/
// 20240508 djb: switch to crypto_sort_int64
// 20221231 djb: remove unused min definition
// 20221231 djb: more 0 initialization to clarify data flow; tnx thom wiggers
// 20221230 djb: add linker lines
// linker define pk_gen
// linker use fft vec_inv vec_mul
#include "pk_gen.h"
#include "controlbits.h"
#include "crypto_sort_int64.h"
#include "params.h"
#include "benes.h"
#include "util.h"
#include "fft.h"
#include "vec.h"
#include "crypto_declassify.h"
#include "crypto_uint64.h"
static crypto_uint64 uint64_is_equal_declassify(uint64_t t,uint64_t u)
{
crypto_uint64 mask = crypto_uint64_equal_mask(t,u);
crypto_declassify(&mask,sizeof mask);
return mask;
}
static crypto_uint64 uint64_is_zero_declassify(uint64_t t)
{
crypto_uint64 mask = crypto_uint64_zero_mask(t);
crypto_declassify(&mask,sizeof mask);
return mask;
}
#include <stdint.h>
static void de_bitslicing(uint64_t * out, const vec in[][GFBITS])
{
int i, j, r;
for (i = 0; i < (1 << GFBITS); i++)
out[i] = 0 ;
for (i = 0; i < 128; i++)
for (j = GFBITS-1; j >= 0; j--)
for (r = 0; r < 64; r++)
{
out[i*64 + r] <<= 1;
out[i*64 + r] |= (in[i][j] >> r) & 1;
}
}
static void to_bitslicing_2x(vec out0[][GFBITS], vec out1[][GFBITS], const uint64_t * in)
{
int i, j, r;
for (i = 0; i < 128; i++)
{
for (j = 0;j < GFBITS;++j) out0[i][j] = out1[i][j] = 0;
for (j = GFBITS-1; j >= 0; j--)
for (r = 63; r >= 0; r--)
{
out1[i][j] <<= 1;
out1[i][j] |= (in[i*64 + r] >> (j + GFBITS)) & 1;
}
for (j = GFBITS-1; j >= 0; j--)
for (r = 63; r >= 0; r--)
{
out0[i][GFBITS-1-j] <<= 1;
out0[i][GFBITS-1-j] |= (in[i*64 + r] >> j) & 1;
}
}
}
/* return number of trailing zeros of in */
static inline int ctz(uint64_t in)
{
int i, b, m = 0, r = 0;
for (i = 0; i < 64; i++)
{
b = (in >> i) & 1;
m |= b;
r += (m^1) & (b^1);
}
return r;
}
static inline uint64_t same_mask(uint16_t x, uint16_t y)
{
uint64_t mask;
mask = x ^ y;
mask -= 1;
mask >>= 63;
mask = -mask;
return mask;
}
static int mov_columns(uint64_t mat[][ 128 ], int16_t * pi, uint64_t * pivots)
{
int i, j, k, s, block_idx, row;
uint64_t buf[64], ctz_list[32], t, d, mask, one = 1;
row = PK_NROWS - 32;
block_idx = row/64;
// extract the 32x64 matrix
for (i = 0; i < 32; i++)
buf[i] = (mat[ row + i ][ block_idx + 0 ] >> 32) |
(mat[ row + i ][ block_idx + 1 ] << 32);
// compute the column indices of pivots by Gaussian elimination.
// the indices are stored in ctz_list
*pivots = 0;
for (i = 0; i < 32; i++)
{
t = buf[i];
for (j = i+1; j < 32; j++)
t |= buf[j];
if (uint64_is_zero_declassify(t)) return -1; // return if buf is not full rank
ctz_list[i] = s = ctz(t);
*pivots |= one << s;
for (j = i+1; j < 32; j++) { mask = (buf[i] >> s) & 1; mask -= 1; buf[i] ^= buf[j] & mask; }
for (j = 0; j < i; j++) { mask = (buf[j] >> s) & 1; mask = -mask; buf[j] ^= buf[i] & mask; }
for (j = i+1; j < 32; j++) { mask = (buf[j] >> s) & 1; mask = -mask; buf[j] ^= buf[i] & mask; }
}
// updating permutation
for (j = 0; j < 32; j++)
for (k = j+1; k < 64; k++)
{
d = pi[ row + j ] ^ pi[ row + k ];
d &= same_mask(k, ctz_list[j]);
pi[ row + j ] ^= d;
pi[ row + k ] ^= d;
}
// moving columns of mat according to the column indices of pivots
for (i = 0; i < PK_NROWS; i++)
{
t = (mat[ i ][ block_idx + 0 ] >> 32) |
(mat[ i ][ block_idx + 1 ] << 32);
for (j = 0; j < 32; j++)
{
d = t >> j;
d ^= t >> ctz_list[j];
d &= 1;
t ^= d << ctz_list[j];
t ^= d << j;
}
mat[ i ][ block_idx + 0 ] = (mat[ i ][ block_idx + 0 ] << 32 >> 32) | (t << 32);
mat[ i ][ block_idx + 1 ] = (mat[ i ][ block_idx + 1 ] >> 32 << 32) | (t >> 32);
}
return 0;
}
int pk_gen(unsigned char * pk, const unsigned char * irr, uint32_t * perm, int16_t * pi, uint64_t * pivots)
{
const int nblocks_H = (SYS_N + 63) / 64;
const int nblocks_I = (PK_NROWS + 63) / 64;
int i, j, k;
int row, c;
uint64_t mat[ PK_NROWS ][ 128 ];
uint64_t mask;
vec irr_int[2][ GFBITS ];
vec consts[ 128 ][ GFBITS ];
vec eval[ 128 ][ GFBITS ];
vec prod[ 128 ][ GFBITS ];
vec tmp[ GFBITS ];
uint64_t list[1 << GFBITS];
// compute the inverses
irr_load(irr_int, irr);
fft(eval, irr_int);
vec_copy(prod[0], eval[0]);
for (i = 1; i < 128; i++)
vec_mul(prod[i], prod[i-1], eval[i]);
vec_inv(tmp, prod[127]);
for (i = 126; i >= 0; i--)
{
vec_mul(prod[i+1], prod[i], tmp);
vec_mul(tmp, tmp, eval[i+1]);
}
vec_copy(prod[0], tmp);
// fill matrix
de_bitslicing(list, prod);
for (i = 0; i < (1 << GFBITS); i++)
{
list[i] <<= GFBITS;
list[i] |= i;
list[i] |= ((uint64_t) perm[i]) << 31;
}
crypto_sort_int64(list, 1 << GFBITS);
for (i = 1; i < (1 << GFBITS); i++)
if (uint64_is_equal_declassify(list[i-1] >> 31,list[i] >> 31))
return -1;
to_bitslicing_2x(consts, prod, list);
for (i = 0; i < (1 << GFBITS); i++)
pi[i] = list[i] & GFMASK;
for (j = 0; j < nblocks_H; j++)
for (k = 0; k < GFBITS; k++)
mat[ k ][ j ] = prod[ j ][ k ];
for (i = 1; i < SYS_T; i++)
for (j = 0; j < nblocks_H; j++)
{
vec_mul(prod[j], prod[j], consts[j]);
for (k = 0; k < GFBITS; k++)
mat[ i*GFBITS + k ][ j ] = prod[ j ][ k ];
}
// gaussian elimination
for (i = 0; i < PK_NROWS / 64; i++)
for (j = 0; j < 64; j++)
{
row = i*64 + j;
if (row == PK_NROWS - 32)
{
if (mov_columns(mat, pi, pivots))
return -1;
}
for (k = row + 1; k < PK_NROWS; k++)
{
mask = mat[ row ][ i ] >> j;
mask &= 1;
mask -= 1;
for (c = 0; c < 128; c++)
mat[ row ][ c ] ^= mat[ k ][ c ] & mask;
}
if ( uint64_is_zero_declassify((mat[ row ][ i ] >> j) & 1) ) // return if not systematic
{
return -1;
}
for (k = 0; k < row; k++)
{
mask = mat[ k ][ i ] >> j;
mask &= 1;
mask = -mask;
for (c = 0; c < 128; c++)
mat[ k ][ c ] ^= mat[ row ][ c ] & mask;
}
for (k = row+1; k < PK_NROWS; k++)
{
mask = mat[ k ][ i ] >> j;
mask &= 1;
mask = -mask;
for (c = 0; c < 128; c++)
mat[ k ][ c ] ^= mat[ row ][ c ] & mask;
}
}
for (i = 0; i < PK_NROWS; i++)
for (j = nblocks_I; j < 128; j++)
{
store8(pk, mat[i][j]);
pk += 8;
}
//
return 0;
}