153 行
3.7 KiB
C
153 行
3.7 KiB
C
/*
|
|
wots.c version 20160722
|
|
Andreas Hülsing
|
|
Joost Rijneveld
|
|
Public domain.
|
|
*/
|
|
|
|
#include "math.h"
|
|
#include "stdio.h"
|
|
#include "stdint.h"
|
|
#include "xmss_commons.h"
|
|
//#include "params.h"
|
|
//#include "prg.h"
|
|
#include "hash.h"
|
|
#include "wots.h"
|
|
#include "hash_address.h"
|
|
#include "params.h"
|
|
|
|
/**
|
|
* Helper method for pseudorandom key generation
|
|
* Expands an n-byte array into a len*n byte array
|
|
* this is done using PRF
|
|
*/
|
|
static void expand_seed(unsigned char *outseeds, const unsigned char *inseed)
|
|
{
|
|
uint32_t i = 0;
|
|
unsigned char ctr[32];
|
|
for(i = 0; i < XMSS_WOTS_LEN; i++){
|
|
to_byte(ctr, i, 32);
|
|
prf(outseeds + i*XMSS_N, ctr, inseed, XMSS_N);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Computes the chaining function.
|
|
* out and in have to be n-byte arrays
|
|
*
|
|
* interpretes in as start-th value of the chain
|
|
* addr has to contain the address of the chain
|
|
*/
|
|
static void gen_chain(unsigned char *out, const unsigned char *in, unsigned int start, unsigned int steps, const unsigned char *pub_seed, uint32_t addr[8])
|
|
{
|
|
uint32_t i, j;
|
|
for (j = 0; j < XMSS_N; j++)
|
|
out[j] = in[j];
|
|
|
|
for (i = start; i < (start+steps) && i < XMSS_WOTS_W; i++) {
|
|
setHashADRS(addr, i);
|
|
hash_f(out, out, pub_seed, addr, XMSS_N);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* base_w algorithm as described in draft.
|
|
*
|
|
*
|
|
*/
|
|
static void base_w(int *output, const int out_len, const unsigned char *input)
|
|
{
|
|
int in = 0;
|
|
int out = 0;
|
|
uint32_t total = 0;
|
|
int bits = 0;
|
|
int consumed = 0;
|
|
|
|
for (consumed = 0; consumed < out_len; consumed++) {
|
|
if (bits == 0) {
|
|
total = input[in];
|
|
in++;
|
|
bits += 8;
|
|
}
|
|
bits -= XMSS_WOTS_LOG_W;
|
|
output[out] = (total >> bits) & (XMSS_WOTS_W - 1);
|
|
out++;
|
|
}
|
|
}
|
|
|
|
void wots_pkgen(unsigned char *pk, const unsigned char *sk, const unsigned char *pub_seed, uint32_t addr[8])
|
|
{
|
|
uint32_t i;
|
|
expand_seed(pk, sk);
|
|
for (i=0; i < XMSS_WOTS_LEN; i++) {
|
|
setChainADRS(addr, i);
|
|
gen_chain(pk+i*XMSS_N, pk+i*XMSS_N, 0, XMSS_WOTS_W-1, pub_seed, addr);
|
|
}
|
|
}
|
|
|
|
|
|
void wots_sign(unsigned char *sig, const unsigned char *msg, const unsigned char *sk, const unsigned char *pub_seed, uint32_t addr[8])
|
|
{
|
|
int basew[XMSS_WOTS_LEN];
|
|
int csum = 0;
|
|
uint32_t i = 0;
|
|
|
|
base_w(basew, XMSS_WOTS_LEN1, msg);
|
|
|
|
for (i=0; i < XMSS_WOTS_LEN1; i++) {
|
|
csum += XMSS_WOTS_W - 1 - basew[i];
|
|
}
|
|
|
|
csum = csum << (8 - ((XMSS_WOTS_LEN2 * XMSS_WOTS_LOG_W) % 8));
|
|
|
|
int len_2_bytes = ((XMSS_WOTS_LEN2 * XMSS_WOTS_LOG_W) + 7) / 8;
|
|
|
|
unsigned char csum_bytes[len_2_bytes];
|
|
to_byte(csum_bytes, csum, len_2_bytes);
|
|
|
|
int csum_basew[len_2_bytes / XMSS_WOTS_LOG_W];
|
|
base_w(csum_basew, XMSS_WOTS_LEN2, csum_bytes);
|
|
|
|
for (i = 0; i < XMSS_WOTS_LEN2; i++) {
|
|
basew[XMSS_WOTS_LEN1 + i] = csum_basew[i];
|
|
}
|
|
|
|
expand_seed(sig, sk);
|
|
|
|
for (i = 0; i < XMSS_WOTS_LEN; i++) {
|
|
setChainADRS(addr, i);
|
|
gen_chain(sig+i*XMSS_N, sig+i*XMSS_N, 0, basew[i], pub_seed, addr);
|
|
}
|
|
}
|
|
|
|
void wots_pkFromSig(unsigned char *pk, const unsigned char *sig, const unsigned char *msg, const unsigned char *pub_seed, uint32_t addr[8])
|
|
{
|
|
int basew[XMSS_WOTS_LEN];
|
|
int csum = 0;
|
|
uint32_t i = 0;
|
|
|
|
base_w(basew, XMSS_WOTS_LEN1, msg);
|
|
|
|
for (i=0; i < XMSS_WOTS_LEN1; i++) {
|
|
csum += XMSS_WOTS_W - 1 - basew[i];
|
|
}
|
|
|
|
csum = csum << (8 - ((XMSS_WOTS_LEN2 * XMSS_WOTS_LOG_W) % 8));
|
|
|
|
int len_2_bytes = ((XMSS_WOTS_LEN2 * XMSS_WOTS_LOG_W) + 7) / 8;
|
|
|
|
unsigned char csum_bytes[len_2_bytes];
|
|
to_byte(csum_bytes, csum, len_2_bytes);
|
|
|
|
int csum_basew[len_2_bytes / XMSS_WOTS_LOG_W];
|
|
base_w(csum_basew, XMSS_WOTS_LEN2, csum_bytes);
|
|
|
|
for (i = 0; i < XMSS_WOTS_LEN2; i++) {
|
|
basew[XMSS_WOTS_LEN1 + i] = csum_basew[i];
|
|
}
|
|
for (i=0; i < XMSS_WOTS_LEN; i++) {
|
|
setChainADRS(addr, i);
|
|
gen_chain(pk+i*XMSS_N, sig+i*XMSS_N, basew[i], XMSS_WOTS_W-1-basew[i], pub_seed, addr);
|
|
}
|
|
}
|