xmss-KAT-generator/hash.c
2016-02-10 15:57:16 +01:00

161 rader
3.3 KiB
C

/*
hash.c version 20151120
Andreas Hülsing
Public domain.
*/
#include "prg.h"
#include <stddef.h>
#include "stdio.h"
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <openssl/evp.h>
#define SET_KEY_BIT(a,b) (a[15] = (a[15] & 253) | (b << 1))
#define SET_BLOCK_BIT(a,b) (a[15] = (a[15] & 254) | b)
#define WOTS_SELECT_KEY(a) (a[15] = (a[15] & 254) | 1)
#define WOTS_SELECT_BLOCK(a) (a[15] = (a[15] & 254) | 0)
/**
* Implements PRF_m
*/
int prf_m(unsigned char *out, const unsigned char *in, size_t inlen, const unsigned char *key, int keylen)
{
unsigned int length;
if (keylen == 32){
HMAC(EVP_sha256(), key, keylen, in, inlen, out, &length);
if(length != 32)
{
fprintf(stderr, "HMAC outputs %d bytes... That should not happen...",length);
}
return 0;
}
else
{
if(keylen == 64)
{
HMAC(EVP_sha512(), key, keylen, in, inlen, out, &length);
if(length != 64)
{
fprintf(stderr, "HMAC outputs %d bytes... That should not happen...",length);
}
return 0;
}
}
return 1;
}
/*
* Implemts H_m
*/
int hash_m(unsigned char *out,const unsigned char *in,unsigned long long inlen,const unsigned char *key, const int keylen, const int m)
{
if(keylen != m){
fprintf(stderr, "H_m takes m-bit keys, we got m=%d but a keylength of %d.\n",m,keylen);
return 1;
}
unsigned long long i;
unsigned char buf[inlen +keylen+m];
for(i=0;i<m;i++)
{
buf[i] = 0x00;
}
for(i=0;i <keylen;i++)
{
buf[m+i] = key[i];
}
for(i=0;i <inlen;i++)
{
buf[m+keylen+i] = in[i];
}
if(m == 32)
{
SHA256(buf,inlen +keylen+m,out);
return 0;
}
else
{
if(m == 64)
{
SHA512(buf,inlen +keylen+m,out);
return 0;
}
}
return 1;
}
/**
* We assume the left half is in in[0]...in[n-1]
*/
int hash_2n_n(unsigned char *out,const unsigned char *in, const unsigned char *pub_seed, unsigned char addr[16], const int n)
{
unsigned char buf[4*n];
unsigned char key[n];
unsigned char bitmask[2*n];
int i;
SET_KEY_BIT(addr,1);
SET_BLOCK_BIT(addr,0);
prg_with_counter(key, pub_seed, n, addr);
SET_KEY_BIT(addr,0);
// Use MSB order
prg_with_counter(bitmask, pub_seed, n, addr);
SET_BLOCK_BIT(addr,1);
prg_with_counter(bitmask+n, pub_seed, n, addr);
for(i=0;i<n;i++)
{
buf[i] = 0x00;
buf[n+i] = key[i];
buf[2*n+i] = in[i] ^ bitmask[i];
buf[3*n+i] = in[n+i] ^ bitmask[n+i];
}
if(n==32){
SHA256(buf,4*n,out);
return 0;
} else {
if(n==64){
SHA512(buf,4*n,out);
return 0;
} else {
fprintf(stderr, "Hash.c:hash_2n_n: Code only supports n=32 or n=64");
return -1;
}
}
}
int hash_n_n(unsigned char *out,const unsigned char *in, const unsigned char *pub_seed, unsigned char addr[16], const int n)
{
unsigned char buf[3*n];
unsigned char key[n];
unsigned char bitmask[n];
int i;
WOTS_SELECT_KEY(addr);
prg_with_counter(key, pub_seed, n, addr);
WOTS_SELECT_BLOCK(addr);
prg_with_counter(bitmask, pub_seed, n, addr);
for(i=0;i<n;i++)
{
buf[i] = 0x00;
buf[n+i] = key[i];
buf[2*n+i] = in[i] ^ bitmask[i];
}
if(n==32){
SHA256(buf,3*n,out);
return 0;
} else {
if(n==64){
SHA512(buf,3*n,out);
return 0;
} else {
fprintf(stderr, "Hash.c:hash_n_n: Code only supports n=32 or n=64");
return -1;
}
}
}