1 // Copyright 2017 Google Inc. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 //////////////////////////////////////////////////////////////////////////////// 16 17 package com.google.crypto.tink; 18 19 import java.security.GeneralSecurityException; 20 21 /** 22 * Interface for Authenticated Encryption with Associated Data (AEAD). 23 * 24 * <h3>Security guarantees</h3> 25 * 26 * <p>Implementations of this interface are secure against adaptive chosen ciphertext attacks. 27 * Encryption with associated data ensures authenticity (who the sender is) and integrity (the data 28 * has not been tampered with) of that data, but not its secrecy. (see <a 29 * href="https://tools.ietf.org/html/rfc5116">RFC 5116</a> for more info) 30 * 31 * @since 1.0.0 32 */ 33 public interface Aead { 34 /** 35 * Encrypts {@code plaintext} with {@code associatedData} as associated authenticated data. 36 * The resulting ciphertext allows for checking authenticity and integrity of associated data 37 * ({@code associatedData}), but does not guarantee its secrecy. 38 * 39 * @param plaintext the plaintext to be encrypted. It must be non-null, but can also 40 * be an empty (zero-length) byte array 41 * @param associatedData associated data to be authenticated, but not encrypted. Associated data 42 * is optional, so this parameter can be null. In this case the null value 43 * is equivalent to an empty (zero-length) byte array. 44 * For successful decryption the same associatedData must be provided 45 * along with the ciphertext. 46 * @return resulting ciphertext 47 */ encrypt(final byte[] plaintext, final byte[] associatedData)48 byte[] encrypt(final byte[] plaintext, final byte[] associatedData) 49 throws GeneralSecurityException; 50 51 /** 52 * Decrypts {@code ciphertext} with {@code associatedData} as associated authenticated data. The 53 * decryption verifies the authenticity and integrity of the associated data, but there are no 54 * guarantees wrt. secrecy of that data. 55 * 56 * @param ciphertext the plaintext to be decrypted. It must be non-null. 57 * @param associatedData associated data to be authenticated. For successful decryption it must be 58 * the same as associatedData used during encryption. Can be null, which is equivalent to an 59 * empty (zero-length) byte array. 60 * @return resulting plaintext 61 * @throws GeneralSecurityException if decryption fails. Decryption must fail if {@code 62 * ciphertext} is not correctly authenticated for the given {@code associatedData}. 63 */ decrypt(final byte[] ciphertext, final byte[] associatedData)64 byte[] decrypt(final byte[] ciphertext, final byte[] associatedData) 65 throws GeneralSecurityException; 66 } 67