382 lines
10 KiB
C
382 lines
10 KiB
C
|
/*
|
||
|
|
* Wrapper for implementing the PQClean API.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <stddef.h>
|
||
|
|
#include <string.h>
|
||
|
|
|
||
|
|
#include "api.h"
|
||
|
|
#include "inner.h"
|
||
|
|
|
||
|
|
#define NONCELEN 40
|
||
|
|
|
||
|
|
#include "randombytes.h"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Encoding formats (nnnn = log of degree, 9 for Falcon-512, 10 for Falcon-1024)
|
||
|
|
*
|
||
|
|
* private key:
|
||
|
|
* header byte: 0101nnnn
|
||
|
|
* private f (6 or 5 bits by element, depending on degree)
|
||
|
|
* private g (6 or 5 bits by element, depending on degree)
|
||
|
|
* private F (8 bits by element)
|
||
|
|
*
|
||
|
|
* public key:
|
||
|
|
* header byte: 0000nnnn
|
||
|
|
* public h (14 bits by element)
|
||
|
|
*
|
||
|
|
* signature:
|
||
|
|
* header byte: 0011nnnn
|
||
|
|
* nonce 40 bytes
|
||
|
|
* value (12 bits by element)
|
||
|
|
*
|
||
|
|
* message + signature:
|
||
|
|
* signature length (2 bytes, big-endian)
|
||
|
|
* nonce 40 bytes
|
||
|
|
* message
|
||
|
|
* header byte: 0010nnnn
|
||
|
|
* value (12 bits by element)
|
||
|
|
* (signature length is 1+len(value), not counting the nonce)
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* see api.h */
|
||
|
|
int
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_crypto_sign_keypair(
|
||
|
|
uint8_t *pk, uint8_t *sk) {
|
||
|
|
union {
|
||
|
|
uint8_t b[FALCON_KEYGEN_TEMP_10];
|
||
|
|
uint64_t dummy_u64;
|
||
|
|
fpr dummy_fpr;
|
||
|
|
} tmp;
|
||
|
|
int8_t f[1024], g[1024], F[1024];
|
||
|
|
uint16_t h[1024];
|
||
|
|
unsigned char seed[48];
|
||
|
|
shake256_context rng;
|
||
|
|
size_t u, v;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Generate key pair.
|
||
|
|
*/
|
||
|
|
randombytes(seed, sizeof seed);
|
||
|
|
shake256_init(&rng);
|
||
|
|
shake256_inject(&rng, seed, sizeof seed);
|
||
|
|
shake256_flip(&rng);
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_keygen(&rng, f, g, F, NULL, h, 10, tmp.b);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Encode private key.
|
||
|
|
*/
|
||
|
|
sk[0] = 0x50 + 10;
|
||
|
|
u = 1;
|
||
|
|
v = PQCLEAN_FALCON1024_CLEAN_trim_i8_encode(
|
||
|
|
sk + u, PQCLEAN_FALCON1024_CLEAN_CRYPTO_SECRETKEYBYTES - u,
|
||
|
|
f, 10, PQCLEAN_FALCON1024_CLEAN_max_fg_bits[10]);
|
||
|
|
if (v == 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
u += v;
|
||
|
|
v = PQCLEAN_FALCON1024_CLEAN_trim_i8_encode(
|
||
|
|
sk + u, PQCLEAN_FALCON1024_CLEAN_CRYPTO_SECRETKEYBYTES - u,
|
||
|
|
g, 10, PQCLEAN_FALCON1024_CLEAN_max_fg_bits[10]);
|
||
|
|
if (v == 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
u += v;
|
||
|
|
v = PQCLEAN_FALCON1024_CLEAN_trim_i8_encode(
|
||
|
|
sk + u, PQCLEAN_FALCON1024_CLEAN_CRYPTO_SECRETKEYBYTES - u,
|
||
|
|
F, 10, PQCLEAN_FALCON1024_CLEAN_max_FG_bits[10]);
|
||
|
|
if (v == 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
u += v;
|
||
|
|
if (u != PQCLEAN_FALCON1024_CLEAN_CRYPTO_SECRETKEYBYTES) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Encode public key.
|
||
|
|
*/
|
||
|
|
pk[0] = 0x00 + 10;
|
||
|
|
v = PQCLEAN_FALCON1024_CLEAN_modq_encode(
|
||
|
|
pk + 1, PQCLEAN_FALCON1024_CLEAN_CRYPTO_PUBLICKEYBYTES - 1,
|
||
|
|
h, 10);
|
||
|
|
if (v != PQCLEAN_FALCON1024_CLEAN_CRYPTO_PUBLICKEYBYTES - 1) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Compute the signature. nonce[] receives the nonce and must have length
|
||
|
|
* NONCELEN bytes. sigbuf[] receives the signature value (without nonce
|
||
|
|
* or header byte), with *sigbuflen providing the maximum value length and
|
||
|
|
* receiving the actual value length.
|
||
|
|
*
|
||
|
|
* If a signature could be computed but not encoded because it would
|
||
|
|
* exceed the output buffer size, then a new signature is computed. If
|
||
|
|
* the provided buffer size is too low, this could loop indefinitely, so
|
||
|
|
* the caller must provide a size that can accommodate signatures with a
|
||
|
|
* large enough probability.
|
||
|
|
*
|
||
|
|
* Return value: 0 on success, -1 on error.
|
||
|
|
*/
|
||
|
|
static int
|
||
|
|
do_sign(uint8_t *nonce, uint8_t *sigbuf, size_t *sigbuflen,
|
||
|
|
const uint8_t *m, size_t mlen, const uint8_t *sk) {
|
||
|
|
union {
|
||
|
|
uint8_t b[72 * 1024];
|
||
|
|
uint64_t dummy_u64;
|
||
|
|
fpr dummy_fpr;
|
||
|
|
} tmp;
|
||
|
|
int8_t f[1024], g[1024], F[1024], G[1024];
|
||
|
|
union {
|
||
|
|
int16_t sig[1024];
|
||
|
|
uint16_t hm[1024];
|
||
|
|
} r;
|
||
|
|
unsigned char seed[48];
|
||
|
|
shake256_context sc;
|
||
|
|
size_t u, v;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Decode the private key.
|
||
|
|
*/
|
||
|
|
if (sk[0] != 0x50 + 10) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
u = 1;
|
||
|
|
v = PQCLEAN_FALCON1024_CLEAN_trim_i8_decode(
|
||
|
|
f, 10, PQCLEAN_FALCON1024_CLEAN_max_fg_bits[10],
|
||
|
|
sk + u, PQCLEAN_FALCON1024_CLEAN_CRYPTO_SECRETKEYBYTES - u);
|
||
|
|
if (v == 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
u += v;
|
||
|
|
v = PQCLEAN_FALCON1024_CLEAN_trim_i8_decode(
|
||
|
|
g, 10, PQCLEAN_FALCON1024_CLEAN_max_fg_bits[10],
|
||
|
|
sk + u, PQCLEAN_FALCON1024_CLEAN_CRYPTO_SECRETKEYBYTES - u);
|
||
|
|
if (v == 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
u += v;
|
||
|
|
v = PQCLEAN_FALCON1024_CLEAN_trim_i8_decode(
|
||
|
|
F, 10, PQCLEAN_FALCON1024_CLEAN_max_FG_bits[10],
|
||
|
|
sk + u, PQCLEAN_FALCON1024_CLEAN_CRYPTO_SECRETKEYBYTES - u);
|
||
|
|
if (v == 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
u += v;
|
||
|
|
if (u != PQCLEAN_FALCON1024_CLEAN_CRYPTO_SECRETKEYBYTES) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
if (!PQCLEAN_FALCON1024_CLEAN_complete_private(G, f, g, F, 10, tmp.b)) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Create a random nonce (40 bytes).
|
||
|
|
*/
|
||
|
|
randombytes(nonce, NONCELEN);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Hash message nonce + message into a vector.
|
||
|
|
*/
|
||
|
|
shake256_init(&sc);
|
||
|
|
shake256_inject(&sc, nonce, NONCELEN);
|
||
|
|
shake256_inject(&sc, m, mlen);
|
||
|
|
shake256_flip(&sc);
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_hash_to_point(&sc, r.hm, 10, tmp.b);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Initialize a RNG.
|
||
|
|
*/
|
||
|
|
randombytes(seed, sizeof seed);
|
||
|
|
shake256_init(&sc);
|
||
|
|
shake256_inject(&sc, seed, sizeof seed);
|
||
|
|
shake256_flip(&sc);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Compute and return the signature. This loops until a signature
|
||
|
|
* value is found that fits in the provided buffer.
|
||
|
|
*/
|
||
|
|
for (;;) {
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_sign_dyn(r.sig, &sc, f, g, F, G, r.hm, 10, tmp.b);
|
||
|
|
v = PQCLEAN_FALCON1024_CLEAN_comp_encode(sigbuf, *sigbuflen, r.sig, 10);
|
||
|
|
if (v != 0) {
|
||
|
|
*sigbuflen = v;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Verify a sigature. The nonce has size NONCELEN bytes. sigbuf[]
|
||
|
|
* (of size sigbuflen) contains the signature value, not including the
|
||
|
|
* header byte or nonce. Return value is 0 on success, -1 on error.
|
||
|
|
*/
|
||
|
|
static int
|
||
|
|
do_verify(
|
||
|
|
const uint8_t *nonce, const uint8_t *sigbuf, size_t sigbuflen,
|
||
|
|
const uint8_t *m, size_t mlen, const uint8_t *pk) {
|
||
|
|
union {
|
||
|
|
uint8_t b[2 * 1024];
|
||
|
|
uint64_t dummy_u64;
|
||
|
|
fpr dummy_fpr;
|
||
|
|
} tmp;
|
||
|
|
uint16_t h[1024], hm[1024];
|
||
|
|
int16_t sig[1024];
|
||
|
|
shake256_context sc;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Decode public key.
|
||
|
|
*/
|
||
|
|
if (pk[0] != 0x00 + 10) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
if (PQCLEAN_FALCON1024_CLEAN_modq_decode(h, 10,
|
||
|
|
pk + 1, PQCLEAN_FALCON1024_CLEAN_CRYPTO_PUBLICKEYBYTES - 1)
|
||
|
|
!= PQCLEAN_FALCON1024_CLEAN_CRYPTO_PUBLICKEYBYTES - 1) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_to_ntt_monty(h, 10);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Decode signature.
|
||
|
|
*/
|
||
|
|
if (sigbuflen == 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
if (PQCLEAN_FALCON1024_CLEAN_comp_decode(sig, 10, sigbuf, sigbuflen) != sigbuflen) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Hash nonce + message into a vector.
|
||
|
|
*/
|
||
|
|
shake256_init(&sc);
|
||
|
|
shake256_inject(&sc, nonce, NONCELEN);
|
||
|
|
shake256_inject(&sc, m, mlen);
|
||
|
|
shake256_flip(&sc);
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_hash_to_point(&sc, hm, 10, tmp.b);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Verify signature.
|
||
|
|
*/
|
||
|
|
if (!PQCLEAN_FALCON1024_CLEAN_verify_raw(hm, sig, h, 10, tmp.b)) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* see api.h */
|
||
|
|
int
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_crypto_sign_signature(
|
||
|
|
uint8_t *sig, size_t *siglen,
|
||
|
|
const uint8_t *m, size_t mlen, const uint8_t *sk) {
|
||
|
|
/*
|
||
|
|
* The PQCLEAN_FALCON1024_CLEAN_CRYPTO_BYTES constant is used for
|
||
|
|
* the signed message object (as produced by crypto_sign())
|
||
|
|
* and includes a two-byte length value, so we take care here
|
||
|
|
* to only generate signatures that are two bytes shorter than
|
||
|
|
* the maximum. This is done to ensure that crypto_sign()
|
||
|
|
* and crypto_sign_signature() produce the exact same signature
|
||
|
|
* value, if used on the same message, with the same private key,
|
||
|
|
* and using the same output from randombytes() (this is for
|
||
|
|
* reproducibility of tests).
|
||
|
|
*/
|
||
|
|
size_t vlen;
|
||
|
|
|
||
|
|
vlen = PQCLEAN_FALCON1024_CLEAN_CRYPTO_BYTES - NONCELEN - 3;
|
||
|
|
if (do_sign(sig + 1, sig + 1 + NONCELEN, &vlen, m, mlen, sk) < 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
sig[0] = 0x30 + 10;
|
||
|
|
*siglen = 1 + NONCELEN + vlen;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* see api.h */
|
||
|
|
int
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_crypto_sign_verify(
|
||
|
|
const uint8_t *sig, size_t siglen,
|
||
|
|
const uint8_t *m, size_t mlen, const uint8_t *pk) {
|
||
|
|
if (siglen < 1 + NONCELEN) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
if (sig[0] != 0x30 + 10) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
return do_verify(sig + 1,
|
||
|
|
sig + 1 + NONCELEN, siglen - 1 - NONCELEN, m, mlen, pk);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* see api.h */
|
||
|
|
int
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_crypto_sign(
|
||
|
|
uint8_t *sm, size_t *smlen,
|
||
|
|
const uint8_t *m, size_t mlen, const uint8_t *sk) {
|
||
|
|
uint8_t *pm, *sigbuf;
|
||
|
|
size_t sigbuflen;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Move the message to its final location; this is a memmove() so
|
||
|
|
* it handles overlaps properly.
|
||
|
|
*/
|
||
|
|
memmove(sm + 2 + NONCELEN, m, mlen);
|
||
|
|
pm = sm + 2 + NONCELEN;
|
||
|
|
sigbuf = pm + 1 + mlen;
|
||
|
|
sigbuflen = PQCLEAN_FALCON1024_CLEAN_CRYPTO_BYTES - NONCELEN - 3;
|
||
|
|
if (do_sign(sm + 2, sigbuf, &sigbuflen, pm, mlen, sk) < 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
pm[mlen] = 0x20 + 10;
|
||
|
|
sigbuflen ++;
|
||
|
|
sm[0] = (uint8_t)(sigbuflen >> 8);
|
||
|
|
sm[1] = (uint8_t)sigbuflen;
|
||
|
|
*smlen = mlen + 2 + NONCELEN + sigbuflen;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* see api.h */
|
||
|
|
int
|
||
|
|
PQCLEAN_FALCON1024_CLEAN_crypto_sign_open(
|
||
|
|
uint8_t *m, size_t *mlen,
|
||
|
|
const uint8_t *sm, size_t smlen, const uint8_t *pk) {
|
||
|
|
const uint8_t *sigbuf;
|
||
|
|
size_t pmlen, sigbuflen;
|
||
|
|
|
||
|
|
if (smlen < 3 + NONCELEN) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
sigbuflen = ((size_t)sm[0] << 8) | (size_t)sm[1];
|
||
|
|
if (sigbuflen < 2 || sigbuflen > (smlen - NONCELEN - 2)) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
sigbuflen --;
|
||
|
|
pmlen = smlen - NONCELEN - 3 - sigbuflen;
|
||
|
|
if (sm[2 + NONCELEN + pmlen] != 0x20 + 10) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
sigbuf = sm + 2 + NONCELEN + pmlen + 1;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The 2-byte length header and the one-byte signature header
|
||
|
|
* have been verified. Nonce is at sm+2, followed by the message
|
||
|
|
* itself. Message length is in pmlen. sigbuf/sigbuflen point to
|
||
|
|
* the signature value (excluding the header byte).
|
||
|
|
*/
|
||
|
|
if (do_verify(sm + 2, sigbuf, sigbuflen,
|
||
|
|
sm + 2 + NONCELEN, pmlen, pk) < 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Signature is correct, we just have to copy/move the message
|
||
|
|
* to its final destination. The memmove() properly handles
|
||
|
|
* overlaps.
|
||
|
|
*/
|
||
|
|
memmove(m, sm + 2 + NONCELEN, pmlen);
|
||
|
|
*mlen = pmlen;
|
||
|
|
return 0;
|
||
|
|
}
|