| /* |
| * Copyright (C) 2019 The Android Open Source Project |
| * |
| * 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.android.server.backup.encryption.tasks; |
| |
| import static java.util.Collections.unmodifiableList; |
| |
| import android.annotation.Nullable; |
| |
| import com.android.server.backup.encryption.chunk.ChunkHash; |
| import com.android.server.backup.encryption.chunking.EncryptedChunk; |
| |
| import java.io.IOException; |
| import java.security.GeneralSecurityException; |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.Set; |
| |
| import javax.crypto.SecretKey; |
| |
| /** Task which reads data from some source, splits it into chunks and encrypts new chunks. */ |
| public interface BackupEncrypter { |
| /** The algorithm which we use to compute the digest of the backup file plaintext. */ |
| String MESSAGE_DIGEST_ALGORITHM = "SHA-256"; |
| |
| /** |
| * Splits the backup input into encrypted chunks and encrypts new chunks. |
| * |
| * @param secretKey Key used to encrypt backup. |
| * @param fingerprintMixerSalt Fingerprint mixer salt used for content-defined chunking during a |
| * full backup. Should be {@code null} for a key-value backup. |
| * @param existingChunks Set of the SHA-256 Macs of chunks the server already has. |
| * @return a result containing an array of new encrypted chunks to upload, and an ordered |
| * listing of the chunks in the backup file. |
| * @throws IOException if a problem occurs reading from the backup data. |
| * @throws GeneralSecurityException if there is a problem encrypting the data. |
| */ |
| Result backup( |
| SecretKey secretKey, |
| @Nullable byte[] fingerprintMixerSalt, |
| Set<ChunkHash> existingChunks) |
| throws IOException, GeneralSecurityException; |
| |
| /** |
| * The result of an incremental backup. Contains new encrypted chunks to upload, and an ordered |
| * list of the chunks in the backup file. |
| */ |
| class Result { |
| private final List<ChunkHash> mAllChunks; |
| private final List<EncryptedChunk> mNewChunks; |
| private final byte[] mDigest; |
| |
| public Result(List<ChunkHash> allChunks, List<EncryptedChunk> newChunks, byte[] digest) { |
| mAllChunks = unmodifiableList(new ArrayList<>(allChunks)); |
| mDigest = digest; |
| mNewChunks = unmodifiableList(new ArrayList<>(newChunks)); |
| } |
| |
| /** |
| * Returns an unmodifiable list of the hashes of all the chunks in the backup, in the order |
| * they appear in the plaintext. |
| */ |
| public List<ChunkHash> getAllChunks() { |
| return mAllChunks; |
| } |
| |
| /** Returns an unmodifiable list of the new chunks in the backup. */ |
| public List<EncryptedChunk> getNewChunks() { |
| return mNewChunks; |
| } |
| |
| /** Returns the message digest of the backup. */ |
| public byte[] getDigest() { |
| return mDigest; |
| } |
| } |
| } |