Function applyHmacKeyDerivationFunc

flow/StreamCipher.cpp:116–124

}

void applyHmacKeyDerivationFunc(StreamCipherKey* cipherKey, HmacSha256StreamCipher* hmacGenerator, Arena& arena) {
	uint8_t buf[cipherKey->size() + sizeof(uint64_t)];
	memcpy(&buf[0], cipherKey->data(), cipherKey->size());
	uint64_t seed = deterministicRandom()->randomUInt64();
	memcpy(&buf[0] + cipherKey->size(), &seed, sizeof(uint64_t));
	StringRef digest = hmacGenerator->digest(&buf[0], cipherKey->size() + sizeof(uint64_t), arena);
	std::copy(digest.begin(), digest.end(), &buf[0]);
	cipherKey->initializeKey(&buf[0], cipherKey->size());
}

EncryptionStreamCipher::EncryptionStreamCipher(const StreamCipherKey* key, const StreamCipher::IV& iv)
  : cipher(StreamCipher(key->size())) {