com.google.crypto.tink.DeterministicAead Maven / Gradle / Ivy
// Copyright 2017 Google Inc.
//
// 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.
//
////////////////////////////////////////////////////////////////////////////////
package com.google.crypto.tink;
import java.security.GeneralSecurityException;
/**
* Interface for Deterministic Authenticated Encryption with Associated Data (Deterministic AEAD).
*
* For why this interface is desirable and some of its use cases, see for example RFC 5297 section 1.3.
*
*
Warning
*
* Unlike {@link Aead}, implementations of this interface are not semantically secure, because
* encrypting the same plaintex always yields the same ciphertext.
*
*
Security guarantees
*
* Implementations of this interface provide 128-bit security level against multi-user attacks
* with up to 2^32 keys. That means if an adversary obtains 2^32 ciphertexts of the same message
* encrypted under 2^32 keys, they need to do 2^128 computations to obtain a single key.
*
*
Encryption with associated data ensures authenticity (who the sender is) and integrity (the
* data has not been tampered with) of that data, but not its secrecy. (see RFC 5116)
*
* @since 1.1.0
*/
public interface DeterministicAead {
/**
* Deterministically encrypts {@code plaintext} with {@code associatedData} as associated
* authenticated data.
*
*
Warning
*
*
Encrypting the same {@code plaintext} multiple times protects the integrity of that
* plaintext, but confidentiality is compromised to the extent that an attacker can determine that
* the same plaintext was encrypted.
*
*
The resulting ciphertext allows for checking authenticity and integrity of associated data
* ({@code associatedData}), but does not guarantee its secrecy.
*
* @return resulting ciphertext
*/
byte[] encryptDeterministically(final byte[] plaintext, final byte[] associatedData)
throws GeneralSecurityException;
/**
* Deterministically decrypts {@code ciphertext} with {@code associatedData} as associated
* authenticated data.
*
*
The decryption verifies the authenticity and integrity of the associated data, but there are
* no guarantees wrt. secrecy of that data.
*
* @return resulting plaintext
*/
byte[] decryptDeterministically(final byte[] ciphertext, final byte[] associatedData)
throws GeneralSecurityException;
}