Made one more cast explicit

This commit is contained in:
Peter Schwabe 2019-02-14 16:18:17 +01:00
parent 393c7a3cde
commit bab1d185cd

View File

@ -84,25 +84,25 @@ int PQCLEAN_KYBER768_crypto_kem_dec(unsigned char *ss, const unsigned char *ct,
unsigned char cmp[KYBER_CIPHERTEXTBYTES];
unsigned char buf[2 * KYBER_SYMBYTES];
unsigned char
kr[2 * KYBER_SYMBYTES]; /* Will contain key, coins, qrom-hash */
kr[2 * KYBER_SYMBYTES]; /* Will contain key, coins, qrom-hash */
const unsigned char *pk = sk + KYBER_INDCPA_SECRETKEYBYTES;
PQCLEAN_KYBER768_indcpa_dec(buf, ct, sk);
for (i = 0; i < KYBER_SYMBYTES; i++) { /* Multitarget countermeasure for coins + contributory KEM */
buf[KYBER_SYMBYTES + i] = sk[KYBER_SECRETKEYBYTES - 2 * KYBER_SYMBYTES + i]; /* Save hash by storing H(pk) in sk */
for (i = 0; i < KYBER_SYMBYTES; i++) { /* Multitarget countermeasure for coins + contributory KEM */
buf[KYBER_SYMBYTES + i] = sk[KYBER_SECRETKEYBYTES - 2 * KYBER_SYMBYTES + i]; /* Save hash by storing H(pk) in sk */
}
sha3_512(kr, buf, 2 * KYBER_SYMBYTES);
PQCLEAN_KYBER768_indcpa_enc(cmp, buf, pk, kr + KYBER_SYMBYTES); /* coins are in kr+KYBER_SYMBYTES */
PQCLEAN_KYBER768_indcpa_enc(cmp, buf, pk, kr + KYBER_SYMBYTES); /* coins are in kr+KYBER_SYMBYTES */
fail = PQCLEAN_KYBER768_verify(ct, cmp, KYBER_CIPHERTEXTBYTES);
sha3_256(kr + KYBER_SYMBYTES, ct, KYBER_CIPHERTEXTBYTES); /* overwrite coins in kr with H(c) */
sha3_256(kr + KYBER_SYMBYTES, ct, KYBER_CIPHERTEXTBYTES); /* overwrite coins in kr with H(c) */
PQCLEAN_KYBER768_cmov(kr, sk + KYBER_SECRETKEYBYTES - KYBER_SYMBYTES, KYBER_SYMBYTES, fail); /* Overwrite pre-k with z on re-encryption failure */
PQCLEAN_KYBER768_cmov(kr, sk + KYBER_SECRETKEYBYTES - KYBER_SYMBYTES, KYBER_SYMBYTES, (unsigned char)fail); /* Overwrite pre-k with z on re-encryption failure */
sha3_256(ss, kr, 2 * KYBER_SYMBYTES); /* hash concatenation of pre-k and H(c) to k */
sha3_256(ss, kr, 2 * KYBER_SYMBYTES); /* hash concatenation of pre-k and H(c) to k */
return 0;
}