| /* |
| * Copyright (C) 2016 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.google.android.exoplayer2.upstream.crypto; |
| |
| import static com.google.common.truth.Truth.assertThat; |
| |
| import androidx.test.ext.junit.runners.AndroidJUnit4; |
| import com.google.android.exoplayer2.testutil.TestUtil; |
| import com.google.android.exoplayer2.util.Util; |
| import java.util.Random; |
| import javax.crypto.Cipher; |
| import org.junit.After; |
| import org.junit.Before; |
| import org.junit.Test; |
| import org.junit.runner.RunWith; |
| |
| /** Unit tests for {@link AesFlushingCipher}. */ |
| @RunWith(AndroidJUnit4.class) |
| public class AesFlushingCipherTest { |
| |
| private static final int DATA_LENGTH = 65536; |
| private static final byte[] KEY = Util.getUtf8Bytes("testKey:12345678"); |
| private static final long NONCE = 0; |
| private static final long START_OFFSET = 11; |
| private static final long RANDOM_SEED = 0x12345678; |
| |
| private AesFlushingCipher encryptCipher; |
| private AesFlushingCipher decryptCipher; |
| |
| @Before |
| public void setUp() { |
| encryptCipher = new AesFlushingCipher(Cipher.ENCRYPT_MODE, KEY, NONCE, START_OFFSET); |
| decryptCipher = new AesFlushingCipher(Cipher.DECRYPT_MODE, KEY, NONCE, START_OFFSET); |
| } |
| |
| @After |
| public void tearDown() { |
| encryptCipher = null; |
| decryptCipher = null; |
| } |
| |
| private static long getMaxUnchangedBytesAllowedPostEncryption(long length) { |
| // Assuming that not more than 10% of the resultant bytes should be identical. |
| // The value of 10% is arbitrary, ciphers standards do not name a value. |
| return length / 10; |
| } |
| |
| // Count the number of bytes that do not match. |
| private static int getDifferingByteCount(byte[] data1, byte[] data2, int startOffset) { |
| int count = 0; |
| for (int i = startOffset; i < data1.length; i++) { |
| if (data1[i] != data2[i]) { |
| count++; |
| } |
| } |
| return count; |
| } |
| |
| // Count the number of bytes that do not match. |
| private static int getDifferingByteCount(byte[] data1, byte[] data2) { |
| return getDifferingByteCount(data1, data2, 0); |
| } |
| |
| // Test a single encrypt and decrypt call. |
| @Test |
| public void single() { |
| byte[] reference = TestUtil.buildTestData(DATA_LENGTH); |
| byte[] data = reference.clone(); |
| |
| encryptCipher.updateInPlace(data, 0, data.length); |
| int unchangedByteCount = data.length - getDifferingByteCount(reference, data); |
| assertThat(unchangedByteCount <= getMaxUnchangedBytesAllowedPostEncryption(data.length)) |
| .isTrue(); |
| |
| decryptCipher.updateInPlace(data, 0, data.length); |
| int differingByteCount = getDifferingByteCount(reference, data); |
| assertThat(differingByteCount).isEqualTo(0); |
| } |
| |
| // Test several encrypt and decrypt calls, each aligned on a 16 byte block size. |
| @Test |
| public void aligned() { |
| byte[] reference = TestUtil.buildTestData(DATA_LENGTH); |
| byte[] data = reference.clone(); |
| Random random = new Random(RANDOM_SEED); |
| |
| int offset = 0; |
| while (offset < data.length) { |
| int bytes = (1 + random.nextInt(50)) * 16; |
| bytes = Math.min(bytes, data.length - offset); |
| assertThat(bytes % 16).isEqualTo(0); |
| encryptCipher.updateInPlace(data, offset, bytes); |
| offset += bytes; |
| } |
| |
| int unchangedByteCount = data.length - getDifferingByteCount(reference, data); |
| assertThat(unchangedByteCount <= getMaxUnchangedBytesAllowedPostEncryption(data.length)) |
| .isTrue(); |
| |
| offset = 0; |
| while (offset < data.length) { |
| int bytes = (1 + random.nextInt(50)) * 16; |
| bytes = Math.min(bytes, data.length - offset); |
| assertThat(bytes % 16).isEqualTo(0); |
| decryptCipher.updateInPlace(data, offset, bytes); |
| offset += bytes; |
| } |
| |
| int differingByteCount = getDifferingByteCount(reference, data); |
| assertThat(differingByteCount).isEqualTo(0); |
| } |
| |
| // Test several encrypt and decrypt calls, not aligned on block boundary. |
| @Test |
| public void unAligned() { |
| byte[] reference = TestUtil.buildTestData(DATA_LENGTH); |
| byte[] data = reference.clone(); |
| Random random = new Random(RANDOM_SEED); |
| |
| // Encrypt |
| int offset = 0; |
| while (offset < data.length) { |
| int bytes = 1 + random.nextInt(4095); |
| bytes = Math.min(bytes, data.length - offset); |
| encryptCipher.updateInPlace(data, offset, bytes); |
| offset += bytes; |
| } |
| |
| int unchangedByteCount = data.length - getDifferingByteCount(reference, data); |
| assertThat(unchangedByteCount <= getMaxUnchangedBytesAllowedPostEncryption(data.length)) |
| .isTrue(); |
| |
| offset = 0; |
| while (offset < data.length) { |
| int bytes = 1 + random.nextInt(4095); |
| bytes = Math.min(bytes, data.length - offset); |
| decryptCipher.updateInPlace(data, offset, bytes); |
| offset += bytes; |
| } |
| |
| int differingByteCount = getDifferingByteCount(reference, data); |
| assertThat(differingByteCount).isEqualTo(0); |
| } |
| |
| // Test decryption starting from the middle of an encrypted block. |
| @Test |
| public void midJoin() { |
| byte[] reference = TestUtil.buildTestData(DATA_LENGTH); |
| byte[] data = reference.clone(); |
| Random random = new Random(RANDOM_SEED); |
| |
| // Encrypt |
| int offset = 0; |
| while (offset < data.length) { |
| int bytes = 1 + random.nextInt(4095); |
| bytes = Math.min(bytes, data.length - offset); |
| encryptCipher.updateInPlace(data, offset, bytes); |
| offset += bytes; |
| } |
| |
| // Verify |
| int unchangedByteCount = data.length - getDifferingByteCount(reference, data); |
| assertThat(unchangedByteCount <= getMaxUnchangedBytesAllowedPostEncryption(data.length)) |
| .isTrue(); |
| |
| // Setup decryption from random location |
| offset = random.nextInt(4096); |
| decryptCipher = new AesFlushingCipher(Cipher.DECRYPT_MODE, KEY, NONCE, offset + START_OFFSET); |
| int remainingLength = data.length - offset; |
| int originalOffset = offset; |
| |
| // Decrypt |
| while (remainingLength > 0) { |
| int bytes = 1 + random.nextInt(4095); |
| bytes = Math.min(bytes, remainingLength); |
| decryptCipher.updateInPlace(data, offset, bytes); |
| offset += bytes; |
| remainingLength -= bytes; |
| } |
| |
| // Verify |
| int differingByteCount = getDifferingByteCount(reference, data, originalOffset); |
| assertThat(differingByteCount).isEqualTo(0); |
| } |
| |
| } |