mirror of
https://github.com/henrydcase/pqc.git
synced 2024-12-04 21:34:01 +00:00
236 lines
8.1 KiB
C
236 lines
8.1 KiB
C
|
/********************************************************************************************
|
||
|
|
* FrodoKEM: Learning with Errors Key Encapsulation
|
||
|
|
*
|
||
|
|
* Abstract: additional functions for FrodoKEM
|
||
|
|
*********************************************************************************************/
|
||
|
|
|
||
|
|
#include <stdint.h>
|
||
|
|
#include <string.h>
|
||
|
|
|
||
|
|
#include "api.h"
|
||
|
|
#include "common.h"
|
||
|
|
#include "params.h"
|
||
|
|
|
||
|
|
#define min(x, y) (((x) < (y)) ? (x) : (y))
|
||
|
|
|
||
|
|
uint16_t PQCLEAN_FRODOKEM976AES_OPT_LE_TO_UINT16(uint16_t n) {
|
||
|
|
return (((uint8_t *) &n)[0] | (((uint8_t *) &n)[1] << 8));
|
||
|
|
}
|
||
|
|
|
||
|
|
uint16_t PQCLEAN_FRODOKEM976AES_OPT_UINT16_TO_LE(uint16_t n) {
|
||
|
|
uint16_t y;
|
||
|
|
uint8_t *z = (uint8_t *) &y;
|
||
|
|
z[0] = n & 0xFF;
|
||
|
|
z[1] = (n & 0xFF00) >> 8;
|
||
|
|
return y;
|
||
|
|
}
|
||
|
|
|
||
|
|
void PQCLEAN_FRODOKEM976AES_OPT_mul_bs(uint16_t *out, const uint16_t *b, const uint16_t *s) {
|
||
|
|
// Multiply by s on the right
|
||
|
|
// Inputs: b (N_BAR x N), s (N x N_BAR)
|
||
|
|
// Output: out = b*s (N_BAR x N_BAR)
|
||
|
|
int i, j, k;
|
||
|
|
|
||
|
|
for (i = 0; i < PARAMS_NBAR; i++) {
|
||
|
|
for (j = 0; j < PARAMS_NBAR; j++) {
|
||
|
|
out[i * PARAMS_NBAR + j] = 0;
|
||
|
|
for (k = 0; k < PARAMS_N; k++) {
|
||
|
|
out[i * PARAMS_NBAR + j] += b[i * PARAMS_N + k] * s[j * PARAMS_N + k];
|
||
|
|
}
|
||
|
|
out[i * PARAMS_NBAR + j] = (uint32_t)(out[i * PARAMS_NBAR + j]) & ((1 << PARAMS_LOGQ) - 1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void PQCLEAN_FRODOKEM976AES_OPT_mul_add_sb_plus_e(uint16_t *out, const uint16_t *b, const uint16_t *s, const uint16_t *e) {
|
||
|
|
// Multiply by s on the left
|
||
|
|
// Inputs: b (N x N_BAR), s (N_BAR x N), e (N_BAR x N_BAR)
|
||
|
|
// Output: out = s*b + e (N_BAR x N_BAR)
|
||
|
|
int i, j, k;
|
||
|
|
|
||
|
|
for (k = 0; k < PARAMS_NBAR; k++) {
|
||
|
|
for (i = 0; i < PARAMS_NBAR; i++) {
|
||
|
|
out[k * PARAMS_NBAR + i] = e[k * PARAMS_NBAR + i];
|
||
|
|
for (j = 0; j < PARAMS_N; j++) {
|
||
|
|
out[k * PARAMS_NBAR + i] += s[k * PARAMS_N + j] * b[j * PARAMS_NBAR + i];
|
||
|
|
}
|
||
|
|
out[k * PARAMS_NBAR + i] = (uint32_t)(out[k * PARAMS_NBAR + i]) & ((1 << PARAMS_LOGQ) - 1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void PQCLEAN_FRODOKEM976AES_OPT_add(uint16_t *out, const uint16_t *a, const uint16_t *b) {
|
||
|
|
// Add a and b
|
||
|
|
// Inputs: a, b (N_BAR x N_BAR)
|
||
|
|
// Output: c = a + b
|
||
|
|
|
||
|
|
for (size_t i = 0; i < (PARAMS_NBAR * PARAMS_NBAR); i++) {
|
||
|
|
out[i] = (a[i] + b[i]) & ((1 << PARAMS_LOGQ) - 1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void PQCLEAN_FRODOKEM976AES_OPT_sub(uint16_t *out, const uint16_t *a, const uint16_t *b) {
|
||
|
|
// Subtract a and b
|
||
|
|
// Inputs: a, b (N_BAR x N_BAR)
|
||
|
|
// Output: c = a - b
|
||
|
|
|
||
|
|
for (size_t i = 0; i < (PARAMS_NBAR * PARAMS_NBAR); i++) {
|
||
|
|
out[i] = (a[i] - b[i]) & ((1 << PARAMS_LOGQ) - 1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void PQCLEAN_FRODOKEM976AES_OPT_key_encode(uint16_t *out, const uint16_t *in) {
|
||
|
|
// Encoding
|
||
|
|
unsigned int i, j, npieces_word = 8;
|
||
|
|
unsigned int nwords = (PARAMS_NBAR * PARAMS_NBAR) / 8;
|
||
|
|
uint64_t temp, mask = ((uint64_t)1 << PARAMS_EXTRACTED_BITS) - 1;
|
||
|
|
uint16_t *pos = out;
|
||
|
|
|
||
|
|
for (i = 0; i < nwords; i++) {
|
||
|
|
temp = 0;
|
||
|
|
for (j = 0; j < PARAMS_EXTRACTED_BITS; j++) {
|
||
|
|
temp |= ((uint64_t)((uint8_t *)in)[i * PARAMS_EXTRACTED_BITS + j]) << (8 * j);
|
||
|
|
}
|
||
|
|
for (j = 0; j < npieces_word; j++) {
|
||
|
|
*pos = (uint16_t)((temp & mask) << (PARAMS_LOGQ - PARAMS_EXTRACTED_BITS));
|
||
|
|
temp >>= PARAMS_EXTRACTED_BITS;
|
||
|
|
pos++;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void PQCLEAN_FRODOKEM976AES_OPT_key_decode(uint16_t *out, const uint16_t *in) {
|
||
|
|
// Decoding
|
||
|
|
unsigned int i, j, index = 0, npieces_word = 8;
|
||
|
|
unsigned int nwords = (PARAMS_NBAR * PARAMS_NBAR) / 8;
|
||
|
|
uint16_t temp, maskex = ((uint16_t)1 << PARAMS_EXTRACTED_BITS) - 1, maskq = ((uint16_t)1 << PARAMS_LOGQ) - 1;
|
||
|
|
uint8_t *pos = (uint8_t *)out;
|
||
|
|
uint64_t templong;
|
||
|
|
|
||
|
|
for (i = 0; i < nwords; i++) {
|
||
|
|
templong = 0;
|
||
|
|
for (j = 0; j < npieces_word; j++) { // temp = floor(in*2^{-11}+0.5)
|
||
|
|
temp = ((in[index] & maskq) + (1 << (PARAMS_LOGQ - PARAMS_EXTRACTED_BITS - 1))) >> (PARAMS_LOGQ - PARAMS_EXTRACTED_BITS);
|
||
|
|
templong |= ((uint64_t)(temp & maskex)) << (PARAMS_EXTRACTED_BITS * j);
|
||
|
|
index++;
|
||
|
|
}
|
||
|
|
for (j = 0; j < PARAMS_EXTRACTED_BITS; j++) {
|
||
|
|
pos[i * PARAMS_EXTRACTED_BITS + j] = (templong >> (8 * j)) & 0xFF;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void PQCLEAN_FRODOKEM976AES_OPT_pack(uint8_t *out, size_t outlen, const uint16_t *in, size_t inlen, uint8_t lsb) {
|
||
|
|
// Pack the input uint16 vector into a char output vector, copying lsb bits from each input element.
|
||
|
|
// If inlen * lsb / 8 > outlen, only outlen * 8 bits are copied.
|
||
|
|
memset(out, 0, outlen);
|
||
|
|
|
||
|
|
size_t i = 0; // whole bytes already filled in
|
||
|
|
size_t j = 0; // whole uint16_t already copied
|
||
|
|
uint16_t w = 0; // the leftover, not yet copied
|
||
|
|
uint8_t bits = 0; // the number of lsb in w
|
||
|
|
|
||
|
|
while (i < outlen && (j < inlen || ((j == inlen) && (bits > 0)))) {
|
||
|
|
/*
|
||
|
|
in: | | |********|********|
|
||
|
|
^
|
||
|
|
j
|
||
|
|
w : | ****|
|
||
|
|
^
|
||
|
|
bits
|
||
|
|
out:|**|**|**|**|**|**|**|**|* |
|
||
|
|
^^
|
||
|
|
ib
|
||
|
|
*/
|
||
|
|
uint8_t b = 0; // bits in out[i] already filled in
|
||
|
|
while (b < 8) {
|
||
|
|
int nbits = min(8 - b, bits);
|
||
|
|
uint16_t mask = (1 << nbits) - 1;
|
||
|
|
uint8_t t = (uint8_t) ((w >> (bits - nbits)) & mask); // the bits to copy from w to out
|
||
|
|
out[i] = out[i] + (t << (8 - b - nbits));
|
||
|
|
b += (uint8_t) nbits;
|
||
|
|
bits -= (uint8_t) nbits;
|
||
|
|
w &= ~(mask << bits); // not strictly necessary; mostly for debugging
|
||
|
|
|
||
|
|
if (bits == 0) {
|
||
|
|
if (j < inlen) {
|
||
|
|
w = in[j];
|
||
|
|
bits = lsb;
|
||
|
|
j++;
|
||
|
|
} else {
|
||
|
|
break; // the input vector is exhausted
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (b == 8) { // out[i] is filled in
|
||
|
|
i++;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void PQCLEAN_FRODOKEM976AES_OPT_unpack(uint16_t *out, size_t outlen, const uint8_t *in, size_t inlen, uint8_t lsb) {
|
||
|
|
// Unpack the input char vector into a uint16_t output vector, copying lsb bits
|
||
|
|
// for each output element from input. outlen must be at least ceil(inlen * 8 / lsb).
|
||
|
|
memset(out, 0, outlen * sizeof(uint16_t));
|
||
|
|
|
||
|
|
size_t i = 0; // whole uint16_t already filled in
|
||
|
|
size_t j = 0; // whole bytes already copied
|
||
|
|
uint8_t w = 0; // the leftover, not yet copied
|
||
|
|
uint8_t bits = 0; // the number of lsb bits of w
|
||
|
|
|
||
|
|
while (i < outlen && (j < inlen || ((j == inlen) && (bits > 0)))) {
|
||
|
|
/*
|
||
|
|
in: | | | | | | |**|**|...
|
||
|
|
^
|
||
|
|
j
|
||
|
|
w : | *|
|
||
|
|
^
|
||
|
|
bits
|
||
|
|
out:| *****| *****| *** | |...
|
||
|
|
^ ^
|
||
|
|
i b
|
||
|
|
*/
|
||
|
|
uint8_t b = 0; // bits in out[i] already filled in
|
||
|
|
while (b < lsb) {
|
||
|
|
int nbits = min(lsb - b, bits);
|
||
|
|
uint16_t mask = (1 << nbits) - 1;
|
||
|
|
uint8_t t = (w >> (bits - nbits)) & mask; // the bits to copy from w to out
|
||
|
|
out[i] = out[i] + (t << (lsb - b - nbits));
|
||
|
|
b += (uint8_t) nbits;
|
||
|
|
bits -= (uint8_t) nbits;
|
||
|
|
w &= ~(mask << bits); // not strictly necessary; mostly for debugging
|
||
|
|
|
||
|
|
if (bits == 0) {
|
||
|
|
if (j < inlen) {
|
||
|
|
w = in[j];
|
||
|
|
bits = 8;
|
||
|
|
j++;
|
||
|
|
} else {
|
||
|
|
break; // the input vector is exhausted
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (b == lsb) { // out[i] is filled in
|
||
|
|
i++;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void PQCLEAN_FRODOKEM976AES_OPT_clear_bytes(uint8_t *mem, size_t n) {
|
||
|
|
// Clear 8-bit bytes from memory. "n" indicates the number of bytes to be zeroed.
|
||
|
|
// This function uses the volatile type qualifier to inform the compiler not to optimize out the memory clearing.
|
||
|
|
volatile uint8_t *v = mem;
|
||
|
|
|
||
|
|
for (size_t i = 0; i < n; i++) {
|
||
|
|
v[i] = 0;
|
||
|
|
}
|
||
|
|
}
|