aes_128_fixed_key_hash.h | Explore in Territory

/*
 * Copyright 2021 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef DISTRIBUTED_POINT_FUNCTIONS_DPF_INTERNAL_AES_128_FIXED_KEY_HASH_H_
#define DISTRIBUTED_POINT_FUNCTIONS_DPF_INTERNAL_AES_128_FIXED_KEY_HASH_H_

#include "absl/numeric/int128.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/types/span.h"
#include "openssl/cipher.h"

namespace distributed_point_functions {

// Aes128FixedKeyHash is a circular correlation-robust hash function based on
// AES. For key `key`, input `in` and output `out`, the hash function is defined
// as
//
//     out[i] = AES.Encrypt(key, sigma(in[i])) ^ sigma(in[i]),
//
// where sigma(x) = (x.high64 ^ x.low64, x.high64). This is the
// circular correlation-robust MMO construction from
// https://eprint.iacr.org/2019/074.pdf (pp. 18-19). Note that unlike
// cryptographic hash functions such as SHA-256, this hash function is *not*
// compressing and is not designed to provide any security guarantees beyond
// circular correlation-robustness. Use with appropriate caution.
class Aes128FixedKeyHash { … };

}  // namespace distributed_point_functions

#endif  // DISTRIBUTED_POINT_FUNCTIONS_DPF_INTERNAL_AES_128_FIXED_KEY_HASH_H_
chromium/third_party/distributed_point_functions/code/dpf/aes_128_fixed_key_hash.h
