static int hmac_dbrg_instantiate_algorithm(struct ccdrbg_state *drbg, unsigned long entropyLength, const void *entropy, unsigned long nonceLength, const void *nonce, unsigned long psLength, const void *ps) { // TODO: The NIST code passes nonce (i.e. HMAC key) to generate, but cc interface isn't set up that way struct ccdrbg_nisthmac_state *state=(struct ccdrbg_nisthmac_state *)drbg; // 1. seed_material = entropy_input || nonce || personalization_string. // 2. Set Key to outlen bits of zeros. cc_zero(state->keysize, state->key); // 3. Set V to outlen/8 bytes of 0x01. CC_MEMSET(state->v, 0x01, state->vsize); // 4. (Key, V) = HMAC_DRBG_Update (seed_material, Key, V). hmac_dbrg_update(drbg, entropyLength, entropy, nonceLength, nonce, psLength, ps); // 5. reseed_counter = 1. state->reseed_counter = 1; return 0; }
/* The HMAC_<DIG> transform looks like: <DIG> (K XOR opad || <DIG> (K XOR ipad || text)) Where K is a n byte key ipad is the byte 0x36 repeated 64 times. opad is the byte 0x5c repeated 64 times. text is the data being protected. */ void cchmac_init(const struct ccdigest_info *di, cchmac_ctx_t hc, unsigned long key_len, const void *key_data) { const unsigned char *key = key_data; /* Set cchmac_data(di, hc) to key ^ opad. */ unsigned long byte = 0; if (key_len <= di->block_size) { for (;byte < key_len; ++byte) { cchmac_data(di, hc)[byte] = key[byte] ^ 0x5c; } } else { /* Key is longer than di->block size, reset it to key=digest(key) */ ccdigest_init(di, cchmac_digest_ctx(di, hc)); ccdigest_update(di, cchmac_digest_ctx(di, hc), key_len, key); ccdigest_final(di, cchmac_digest_ctx(di, hc), cchmac_data(di, hc)); key_len = di->output_size; for (;byte < key_len; ++byte) { cchmac_data(di, hc)[byte] ^= 0x5c; } } /* Fill remainder of cchmac_data(di, hc) with opad. */ if (key_len < di->block_size) { CC_MEMSET(cchmac_data(di, hc) + key_len, 0x5c, di->block_size - key_len); } /* Set cchmac_ostate32(di, hc) to the state of the first round of the outer digest. */ ccdigest_copy_state(di, cchmac_ostate32(di, hc), di->initial_state); di->compress(cchmac_ostate(di, hc), 1, cchmac_data(di, hc)); /* Set cchmac_data(di, hc) to key ^ ipad. */ for (byte = 0; byte < di->block_size; ++byte) { cchmac_data(di, hc)[byte] ^= (0x5c ^ 0x36); } ccdigest_copy_state(di, cchmac_istate32(di, hc), di->initial_state); di->compress(cchmac_istate(di, hc), 1, cchmac_data(di, hc)); cchmac_num(di, hc) = 0; cchmac_nbits(di, hc) = di->block_size * 8; }