/** libkeccak-tiny
*
* A single-file implementation of SHA-3 and SHAKE.
*
* Implementor: David Leon Gil
* License: CC0, attribution kindly requested. Blame taken too,
* but not liability.
*/
#include "sha3-unrolled.h"
#include <string.h>
#include <byteswap.h>
/******** Endianness conversion helpers ********/
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define le64toh(n) (n)
#else
#define le64toh(n) bswap_64(n)
#endif
static inline uint64_t
loadu64le(const unsigned char *x) {
uint64_t r;
memcpy(&r, x, sizeof(r));
return le64toh(r);
}
static inline void
storeu64le(uint8_t *x, uint64_t u) {
uint64_t val = le64toh(u);
memcpy(x, &val, sizeof(u));
}
/******** The Keccak-f[1600] permutation ********/
/*** Constants. ***/
static const uint8_t rho[24] = \
{ 1, 3, 6, 10, 15, 21,
28, 36, 45, 55, 2, 14,
27, 41, 56, 8, 25, 43,
62, 18, 39, 61, 20, 44};
static const uint8_t pi[24] = \
{10, 7, 11, 17, 18, 3,
5, 16, 8, 21, 24, 4,
15, 23, 19, 13, 12, 2,
20, 14, 22, 9, 6, 1};
static const uint64_t RC[24] = \
{1ULL, 0x8082ULL, 0x800000000000808aULL, 0x8000000080008000ULL,
0x808bULL, 0x80000001ULL, 0x8000000080008081ULL, 0x8000000000008009ULL,
0x8aULL, 0x88ULL, 0x80008009ULL, 0x8000000aULL,
0x8000808bULL, 0x800000000000008bULL, 0x8000000000008089ULL, 0x8000000000008003ULL,
0x8000000000008002ULL, 0x8000000000000080ULL, 0x800aULL, 0x800000008000000aULL,
0x8000000080008081ULL, 0x8000000000008080ULL, 0x80000001ULL, 0x8000000080008008ULL};
/*** Helper macros to unroll the permutation. ***/
#define rol(x, s) (((x) << s) | ((x) >> (64 - s)))
#define REPEAT6(e) e e e e e e
#define REPEAT24(e) REPEAT6(e e e e)
#define REPEAT5(e) e e e e e
#define FOR5(v, s, e) \
v = 0; \
REPEAT5(e; v += s;)
/*** Keccak-f[1600] ***/
static inline void keccakf(void* state) {
uint64_t* a = (uint64_t*)state;
uint64_t b[5] = {0};
uint64_t t = 0;
uint8_t x, y, i = 0;
REPEAT24(
// Theta
FOR5(x, 1,
b[x] = 0;
FOR5(y, 5,
b[x] ^= a[x + y]; ))
FOR5(x, 1,
FOR5(y, 5,
a[y + x] ^= b[(x + 4) % 5] ^ rol(b[(x + 1) % 5], 1); ))
// Rho and pi
t = a[1];
x = 0;
REPEAT24(b[0] = a[pi[x]];
a[pi[x]] = rol(t, rho[x]);
t = b[0];
x++; )
// Chi
FOR5(y,
5,
FOR5(x, 1,
b[x] = a[y + x];)
FOR5(x, 1,
a[y + x] = b[x] ^ ((~b[(x + 1) % 5]) & b[(x + 2) % 5]); ))
// Iota
a[0] ^= RC[i];
i++; )
}
/******** The FIPS202-defined functions. ********/
/*** Some helper macros. ***/
// `xorin` modified to handle Big Endian systems, `buf` being unaligned on
// systems that care about such things. Assumes that len is a multiple of 8,
// which is always true for the rates we use, and the modified finalize.
static inline void
xorin8(uint8_t *dst, const uint8_t *src, size_t len) {
uint64_t* a = (uint64_t*)dst; // Always aligned.
for (size_t i = 0; i < len; i += 8) {
a[i/8] ^= loadu64le(src + i);
}
}
// `setout` likewise modified to handle Big Endian systems. Assumes that len
// is a multiple of 8, which is true for every rate we use.
static inline void
setout8(const uint8_t *src, uint8_t *dst, size_t len) {
const uint64_t *si = (const uint64_t*)src; // Always aligned.
for (size_t i = 0; i < len; i+= 8) {
storeu64le(dst+i, si[i/8]);
}
}
#define P keccakf
#define Plen KECCAK_MAX_RATE
#define KECCAK_DELIM_DIGEST 0x06
#define KECCAK_DELIM_XOF 0x1f
// Fold P*F over the full blocks of an input.
#define foldP(I, L, F) \
while (L >= s->rate) { \
F(s->a, I, s->rate); \
P(s->a); \
I += s->rate; \
L -= s->rate; \
}
static inline void
keccak_absorb_blocks(keccak_state *s, const uint8_t *buf, size_t nr_blocks)
{
size_t blen = nr_blocks * s->rate;
foldP(buf, blen, xorin8);
}
static int
keccak_update(keccak_state *s, const uint8_t *buf, size_t len)
{
if (s->finalized)
return -1;
if ((buf == NULL) && len != 0)
return -1;
size_t remaining = len;
while (remaining > 0) {
if (s->offset == 0) {
const size_t blocks = remaining / s->rate;
size_t direct_bytes = blocks * s->rate;
if (direct_bytes > 0) {
keccak_absorb_blocks(s, buf, blocks);
remaining -= direct_bytes;
buf += direct_bytes;
}
}
const size_t buf_avail = s->rate - s->offset;
const size_t buf_bytes = (buf_avail > remaining) ? remaining : buf_avail;
if (buf_bytes > 0) {
memcpy(&s->block[s->offset], buf, buf_bytes);
s->offset += buf_bytes;
remaining -= buf_bytes;
buf += buf_bytes;
}
if (s->offset == s->rate) {
keccak_absorb_blocks(s, s->block, 1);
s->offset = 0;
}
}
return 0;
}
static void
keccak_finalize(keccak_state *s)
{
// Xor in the DS and pad frame.
s->block[s->offset++] = s->delim; // DS.
for (size_t i = s->offset; i < s->rate; i++) {
s->block[i] = 0;
}
s->block[s->rate - 1] |= 0x80; // Pad frame.
// Xor in the last block.
xorin8(s->a, s->block, s->rate);
memset(s->block, 0, sizeof(s->block));
s->finalized = 1;
s->offset = s->rate;
}
static inline void
keccak_squeeze_blocks(keccak_state *s, uint8_t *out, size_t nr_blocks)
{
for (size_t n = 0; n < nr_blocks; n++) {
keccakf(s->a);
setout8(s->a, out, s->rate);
out += s->rate;
}
}
static int
keccak_squeeze(keccak_state *s, uint8_t *out, size_t outlen)
{
if (!s->finalized)
return -1;
size_t remaining = outlen;
while (remaining > 0) {
if (s->offset == s->rate) {
const size_t blocks = remaining / s->rate;
const size_t direct_bytes = blocks * s->rate;
if (blocks > 0) {
keccak_squeeze_blocks(s, out, blocks);
out += direct_bytes;
remaining -= direct_bytes;
}
if (remaining > 0) {
keccak_squeeze_blocks(s, s->block, 1);
s->offset = 0;
}
}
const size_t buf_bytes = s->rate - s->offset;
const size_t indirect_bytes = (buf_bytes > remaining) ? remaining : buf_bytes;
if (indirect_bytes > 0) {
memcpy(out, &s->block[s->offset], indirect_bytes);
out += indirect_bytes;
s->offset += indirect_bytes;
remaining -= indirect_bytes;
}
}
return 0;
}
int
keccak_digest_init(keccak_state *s, size_t bits)
{
if (s == NULL)
return -1;
if (bits != 224 && bits != 256 && bits != 384 && bits != 512)
return -1;
keccak_cleanse(s);
s->rate = KECCAK_RATE(bits);
s->delim = KECCAK_DELIM_DIGEST;
return 0;
}
int
keccak_digest_update(keccak_state *s, const uint8_t *buf, size_t len)
{
if (s == NULL)
return -1;
if (s->delim != KECCAK_DELIM_DIGEST)
return -1;
return keccak_update(s, buf, len);
}
int
keccak_digest_sum(const keccak_state *s, uint8_t *out, size_t outlen)
{
if (s == NULL)
return -1;
if (s->delim != KECCAK_DELIM_DIGEST)
return -1;
if (out == NULL || outlen > 4 * (KECCAK_MAX_RATE - s->rate) / 8)
return -1;
// Work in a copy so that incremental/rolling hashes are easy.
keccak_state s_tmp;
keccak_clone(&s_tmp, s);
keccak_finalize(&s_tmp);
int ret = keccak_squeeze(&s_tmp, out, outlen);
keccak_cleanse(&s_tmp);
return ret;
}
int
keccak_xof_init(keccak_state *s, size_t bits)
{
if (s == NULL)
return -1;
if (bits != 128 && bits != 256)
return -1;
keccak_cleanse(s);
s->rate = KECCAK_RATE(bits);
s->delim = KECCAK_DELIM_XOF;
return 0;
}
int
keccak_xof_absorb(keccak_state *s, const uint8_t *buf, size_t len)
{
if (s == NULL)
return -1;
if (s->delim != KECCAK_DELIM_XOF)
return -1;
return keccak_update(s, buf, len);
}
int
keccak_xof_squeeze(keccak_state *s, uint8_t *out, size_t outlen)
{
if (s == NULL)
return -1;
if (s->delim != KECCAK_DELIM_XOF)
return -1;
if (!s->finalized)
keccak_finalize(s);
return keccak_squeeze(s, out, outlen);
}
void
keccak_clone(keccak_state *out, const keccak_state *in)
{
memcpy(out, in, sizeof(keccak_state));
}
void
keccak_cleanse(keccak_state *s)
{
memset(s, 0, sizeof(keccak_state));
}
/** The sponge-based hash construction. **/
static inline int hash(uint8_t* out, size_t outlen,
const uint8_t* in, size_t inlen,
size_t bits, uint8_t delim) {
if ((out == NULL) || ((in == NULL) && inlen != 0)) {
return -1;
}
int ret = 0;
keccak_state s;
keccak_cleanse(&s);
switch (delim) {
case KECCAK_DELIM_DIGEST:
ret |= keccak_digest_init(&s, bits);
ret |= keccak_digest_update(&s, in, inlen);
// Use the internal API instead of sum to avoid the memcpy.
keccak_finalize(&s);
ret |= keccak_squeeze(&s, out, outlen);
break;
case KECCAK_DELIM_XOF:
ret |= keccak_xof_init(&s, bits);
ret |= keccak_xof_absorb(&s, in, inlen);
ret |= keccak_xof_squeeze(&s, out, outlen);
break;
default:
return -1;
}
keccak_cleanse(&s);
return ret;
}
/*** Helper macros to define SHA3 and SHAKE instances. ***/
#define defshake(bits) \
int shake##bits(uint8_t* out, size_t outlen, \
const uint8_t* in, size_t inlen) { \
return hash(out, outlen, in, inlen, bits, KECCAK_DELIM_XOF); \
}
#define defsha3(bits) \
int sha3_##bits(uint8_t* out, size_t outlen, \
const uint8_t* in, size_t inlen) { \
if (outlen > (bits/8)) { \
return -1; \
} \
return hash(out, outlen, in, inlen, bits, KECCAK_DELIM_DIGEST); \
}
/*** FIPS202 SHAKE VOFs ***/
defshake(128)
defshake(256)
/*** FIPS202 SHA3 FOFs ***/
defsha3(224)
defsha3(256)
defsha3(384)
defsha3(512)