int chacha_test(void)
{
#ifndef LTC_TEST
return CRYPT_NOP;
#else
unsigned long len;
unsigned char out[1000];
/* https://tools.ietf.org/html/rfc7539#section-2.4.2 */
unsigned char k[] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f };
unsigned char n[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x4a, 0x00, 0x00, 0x00, 0x00 };
unsigned char ct[] = { 0x6E, 0x2E, 0x35, 0x9A, 0x25, 0x68, 0xF9, 0x80, 0x41, 0xBA, 0x07, 0x28, 0xDD, 0x0D, 0x69, 0x81,
0xE9, 0x7E, 0x7A, 0xEC, 0x1D, 0x43, 0x60, 0xC2, 0x0A, 0x27, 0xAF, 0xCC, 0xFD, 0x9F, 0xAE, 0x0B,
0xF9, 0x1B, 0x65, 0xC5, 0x52, 0x47, 0x33, 0xAB, 0x8F, 0x59, 0x3D, 0xAB, 0xCD, 0x62, 0xB3, 0x57,
0x16, 0x39, 0xD6, 0x24, 0xE6, 0x51, 0x52, 0xAB, 0x8F, 0x53, 0x0C, 0x35, 0x9F, 0x08, 0x61, 0xD8,
0x07, 0xCA, 0x0D, 0xBF, 0x50, 0x0D, 0x6A, 0x61, 0x56, 0xA3, 0x8E, 0x08, 0x8A, 0x22, 0xB6, 0x5E,
0x52, 0xBC, 0x51, 0x4D, 0x16, 0xCC, 0xF8, 0x06, 0x81, 0x8C, 0xE9, 0x1A, 0xB7, 0x79, 0x37, 0x36,
0x5A, 0xF9, 0x0B, 0xBF, 0x74, 0xA3, 0x5B, 0xE6, 0xB4, 0x0B, 0x8E, 0xED, 0xF2, 0x78, 0x5E, 0x42,
0x87, 0x4D };
char pt[] = "Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, sunscreen would be it.";
chacha_state st;
int err;
len = strlen(pt);
/* crypt piece by piece - using chacha_ivctr32() */
if ((err = chacha_setup(&st, k, sizeof(k), 20)) != CRYPT_OK) return err;
if ((err = chacha_ivctr32(&st, n, sizeof(n), 1)) != CRYPT_OK) return err;
if ((err = chacha_crypt(&st, (unsigned char*)pt, 35, out )) != CRYPT_OK) return err;
if ((err = chacha_crypt(&st, (unsigned char*)pt + 35, 35, out + 35)) != CRYPT_OK) return err;
if ((err = chacha_crypt(&st, (unsigned char*)pt + 70, 5, out + 70)) != CRYPT_OK) return err;
if ((err = chacha_crypt(&st, (unsigned char*)pt + 75, 5, out + 75)) != CRYPT_OK) return err;
if ((err = chacha_crypt(&st, (unsigned char*)pt + 80, len - 80, out + 80)) != CRYPT_OK) return err;
if (compare_testvector(out, len, ct, sizeof(ct), "CHACHA-TV1", 1)) return CRYPT_FAIL_TESTVECTOR;
/* crypt in one go - using chacha_ivctr32() */
if ((err = chacha_setup(&st, k, sizeof(k), 20)) != CRYPT_OK) return err;
if ((err = chacha_ivctr32(&st, n, sizeof(n), 1)) != CRYPT_OK) return err;
if ((err = chacha_crypt(&st, (unsigned char*)pt, len, out)) != CRYPT_OK) return err;
if (compare_testvector(out, len, ct, sizeof(ct), "CHACHA-TV2", 1)) return CRYPT_FAIL_TESTVECTOR;
/* crypt in one go - using chacha_ivctr64() */
if ((err = chacha_setup(&st, k, sizeof(k), 20)) != CRYPT_OK) return err;
if ((err = chacha_ivctr64(&st, n + 4, sizeof(n) - 4, 1)) != CRYPT_OK) return err;
if ((err = chacha_crypt(&st, (unsigned char*)pt, len, out)) != CRYPT_OK) return err;
if (compare_testvector(out, len, ct, sizeof(ct), "CHACHA-TV3", 1)) return CRYPT_FAIL_TESTVECTOR;
/* crypt in a single call using 32-bit counter with a value of 1 */
if ((err = chacha_memory(k, sizeof(k), 20,
n, sizeof(n), 1, (unsigned char*)pt, len, out)) != CRYPT_OK) return err;
if (compare_testvector(out, len, ct, sizeof(ct), "CHACHA-TV4", 1)) return CRYPT_FAIL_TESTVECTOR;
/* crypt in a single call using 64-bit counter with a value of 1 */
if ((err = chacha_memory(k, sizeof(k), 20,
n + 4, sizeof(n) - 4, 1, (unsigned char*)pt, len, out)) != CRYPT_OK) return err;
if (compare_testvector(out, len, ct, sizeof(ct), "CHACHA-TV5", 1)) return CRYPT_FAIL_TESTVECTOR;
return CRYPT_OK;
#endif
}
/**
Add entropy to the PRNG state
@param in The data to add
@param inlen Length of the data to add
@param prng PRNG state to update
@return CRYPT_OK if successful
*/
int chacha20_prng_add_entropy(const unsigned char *in, unsigned long inlen, prng_state *prng)
{
unsigned char buf[40];
unsigned long i;
int err;
LTC_ARGCHK(prng != NULL);
LTC_ARGCHK(in != NULL);
LTC_ARGCHK(inlen > 0);
LTC_MUTEX_LOCK(&prng->lock);
if (prng->ready) {
/* chacha20_prng_ready() was already called, do "rekey" operation */
if ((err = chacha_keystream(&prng->chacha.s, buf, sizeof(buf))) != CRYPT_OK) goto LBL_UNLOCK;
for(i = 0; i < inlen; i++) buf[i % sizeof(buf)] ^= in[i];
/* key 32 bytes, 20 rounds */
if ((err = chacha_setup(&prng->chacha.s, buf, 32, 20)) != CRYPT_OK) goto LBL_UNLOCK;
/* iv 8 bytes */
if ((err = chacha_ivctr64(&prng->chacha.s, buf + 32, 8, 0)) != CRYPT_OK) goto LBL_UNLOCK;
/* clear KEY + IV */
zeromem(buf, sizeof(buf));
}
else {
/* chacha20_prng_ready() was not called yet, add entropy to ent buffer */
while (inlen--) prng->chacha.ent[prng->chacha.idx++ % sizeof(prng->chacha.ent)] ^= *in++;
}
err = CRYPT_OK;
LBL_UNLOCK:
LTC_MUTEX_UNLOCK(&prng->lock);
return err;
}
/**
Make the PRNG ready to read from
@param prng The PRNG to make active
@return CRYPT_OK if successful
*/
int chacha20_prng_ready(prng_state *prng)
{
int err;
LTC_ARGCHK(prng != NULL);
LTC_MUTEX_LOCK(&prng->lock);
if (prng->ready) { err = CRYPT_OK; goto LBL_UNLOCK; }
/* key 32 bytes, 20 rounds */
if ((err = chacha_setup(&prng->chacha.s, prng->chacha.ent, 32, 20)) != CRYPT_OK) goto LBL_UNLOCK;
/* iv 8 bytes */
if ((err = chacha_ivctr64(&prng->chacha.s, prng->chacha.ent + 32, 8, 0)) != CRYPT_OK) goto LBL_UNLOCK;
XMEMSET(&prng->chacha.ent, 0, sizeof(prng->chacha.ent));
prng->chacha.idx = 0;
prng->ready = 1;
LBL_UNLOCK:
LTC_MUTEX_UNLOCK(&prng->lock);
return err;
}
