| // 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.subtle; |
| |
| import static org.junit.Assert.assertArrayEquals; |
| import static org.junit.Assert.assertEquals; |
| import static org.junit.Assert.fail; |
| |
| import com.google.crypto.tink.testing.TestUtil; |
| import com.google.crypto.tink.testing.WycheproofTestUtil; |
| import java.security.GeneralSecurityException; |
| import java.util.Arrays; |
| import javax.crypto.AEADBadTagException; |
| import javax.crypto.Cipher; |
| import org.json.JSONArray; |
| import org.json.JSONObject; |
| import org.junit.Before; |
| import org.junit.Test; |
| import org.junit.runner.RunWith; |
| import org.junit.runners.JUnit4; |
| |
| /** |
| * Unit tests for AesEax. |
| * |
| * <p>TODO: Add more tests: |
| * |
| * <ul> |
| * <li>- maybe add NIST style verification. |
| * <li>- tests with long ciphertexts (e.g. BC had a bug with messages of size 8k or longer) |
| * <li>- check that IVs are distinct. |
| * <li>- use Github Wycheproof test vectors once they're published (b/66825199). |
| * </ul> |
| */ |
| @RunWith(JUnit4.class) |
| public class AesEaxJceTest { |
| private static final int KEY_SIZE = 16; |
| private static final int IV_SIZE = 16; |
| private Integer[] keySizeInBytes; |
| private Integer[] ivSizeInBytes; |
| |
| @Before |
| public void setUp() throws Exception { |
| if (Cipher.getMaxAllowedKeyLength("AES") < 256) { |
| System.out.println( |
| "Unlimited Strength Jurisdiction Policy Files are required" |
| + " but not installed. Skip tests with keys larger than 128 bits."); |
| keySizeInBytes = new Integer[] {16}; |
| } else { |
| keySizeInBytes = new Integer[] {16, 32}; |
| } |
| ivSizeInBytes = new Integer[] {12, 16}; |
| } |
| |
| @Test |
| public void testWycheproofVectors() throws Exception { |
| JSONObject json = |
| WycheproofTestUtil.readJson("../wycheproof/testvectors/aes_eax_test.json"); |
| int errors = 0; |
| int cntSkippedTests = 0; |
| JSONArray testGroups = json.getJSONArray("testGroups"); |
| for (int i = 0; i < testGroups.length(); i++) { |
| JSONObject group = testGroups.getJSONObject(i); |
| int keySize = group.getInt("keySize"); |
| int ivSize = group.getInt("ivSize"); |
| JSONArray tests = group.getJSONArray("tests"); |
| if (!Arrays.asList(keySizeInBytes).contains(keySize / 8) |
| || !Arrays.asList(ivSizeInBytes).contains(ivSize / 8)) { |
| cntSkippedTests += tests.length(); |
| continue; |
| } |
| for (int j = 0; j < tests.length(); j++) { |
| JSONObject testcase = tests.getJSONObject(j); |
| String tcId = |
| String.format( |
| "testcase %d (%s)", testcase.getInt("tcId"), testcase.getString("comment")); |
| byte[] iv = Hex.decode(testcase.getString("iv")); |
| byte[] key = Hex.decode(testcase.getString("key")); |
| byte[] msg = Hex.decode(testcase.getString("msg")); |
| byte[] aad = Hex.decode(testcase.getString("aad")); |
| byte[] ct = Hex.decode(testcase.getString("ct")); |
| byte[] tag = Hex.decode(testcase.getString("tag")); |
| byte[] ciphertext = Bytes.concat(iv, ct, tag); |
| String result = testcase.getString("result"); |
| try { |
| AesEaxJce eax = new AesEaxJce(key, iv.length); |
| byte[] decrypted = eax.decrypt(ciphertext, aad); |
| boolean eq = TestUtil.arrayEquals(decrypted, msg); |
| if (result.equals("invalid")) { |
| System.out.printf( |
| "FAIL %s: accepting invalid ciphertext, cleartext: %s, decrypted: %s%n", |
| tcId, Hex.encode(msg), Hex.encode(decrypted)); |
| errors++; |
| } else { |
| if (!eq) { |
| System.out.printf( |
| "FAIL %s: incorrect decryption, result: %s, expected: %s%n", |
| tcId, Hex.encode(decrypted), Hex.encode(msg)); |
| errors++; |
| } |
| } |
| } catch (GeneralSecurityException ex) { |
| if (result.equals("valid")) { |
| System.out.printf("FAIL %s: cannot decrypt, exception %s%n", tcId, ex); |
| errors++; |
| } |
| } |
| } |
| } |
| System.out.printf("Number of tests skipped: %d", cntSkippedTests); |
| assertEquals(0, errors); |
| } |
| |
| @Test |
| public void testEncryptDecrypt() throws Exception { |
| byte[] aad = new byte[] {1, 2, 3}; |
| byte[] key = Random.randBytes(KEY_SIZE); |
| AesEaxJce eax = new AesEaxJce(key, IV_SIZE); |
| for (int messageSize = 0; messageSize < 75; messageSize++) { |
| byte[] message = Random.randBytes(messageSize); |
| byte[] ciphertext = eax.encrypt(message, aad); |
| byte[] decrypted = eax.decrypt(ciphertext, aad); |
| assertArrayEquals(message, decrypted); |
| } |
| } |
| |
| @Test |
| public void testModifyCiphertext() throws Exception { |
| testModifyCiphertext(16, 16); |
| testModifyCiphertext(16, 12); |
| // TODO(bleichen): Skipping test with key sizes larger than 128 bits because of b/35928521. |
| // testModifyCiphertext(24, 16); |
| // testModifyCiphertext(32, 16); |
| } |
| |
| public void testModifyCiphertext(int keySizeInBytes, int ivSizeInBytes) throws Exception { |
| byte[] aad = new byte[] {1, 2, 3}; |
| byte[] key = Random.randBytes(KEY_SIZE); |
| byte[] message = Random.randBytes(32); |
| AesEaxJce eax = new AesEaxJce(key, ivSizeInBytes); |
| byte[] ciphertext = eax.encrypt(message, aad); |
| |
| // Flipping bits |
| for (int b = 0; b < ciphertext.length; b++) { |
| for (int bit = 0; bit < 8; bit++) { |
| byte[] modified = Arrays.copyOf(ciphertext, ciphertext.length); |
| modified[b] ^= (byte) (1 << bit); |
| try { |
| byte[] unused = eax.decrypt(modified, aad); |
| fail("Decrypting modified ciphertext should fail"); |
| } catch (AEADBadTagException ex) { |
| // This is expected. |
| } |
| } |
| } |
| |
| // Truncate the message. |
| for (int length = 0; length < ciphertext.length; length++) { |
| byte[] modified = Arrays.copyOf(ciphertext, length); |
| try { |
| byte[] unused = eax.decrypt(modified, aad); |
| fail("Decrypting modified ciphertext should fail"); |
| } catch (GeneralSecurityException ex) { |
| // This is expected. |
| // This could be a AeadBadTagException when the tag verification |
| // fails or some not yet specified Exception when the ciphertext is too short. |
| // In all cases a GeneralSecurityException or a subclass of it must be thrown. |
| } |
| } |
| |
| // Modify AAD |
| for (int b = 0; b < aad.length; b++) { |
| for (int bit = 0; bit < 8; bit++) { |
| byte[] modified = Arrays.copyOf(aad, aad.length); |
| modified[b] ^= (byte) (1 << bit); |
| try { |
| byte[] unused = eax.decrypt(ciphertext, modified); |
| fail("Decrypting with modified aad should fail"); |
| } catch (AEADBadTagException ex) { |
| // This is expected. |
| } |
| } |
| } |
| } |
| |
| @Test |
| public void testNullPlaintextOrCiphertext() throws Exception { |
| AesEaxJce eax = new AesEaxJce(Random.randBytes(KEY_SIZE), IV_SIZE); |
| try { |
| byte[] aad = new byte[] {1, 2, 3}; |
| byte[] unused = eax.encrypt(null, aad); |
| fail("Encrypting a null plaintext should fail"); |
| } catch (NullPointerException ex) { |
| // This is expected. |
| } |
| try { |
| byte[] unused = eax.encrypt(null, null); |
| fail("Encrypting a null plaintext should fail"); |
| } catch (NullPointerException ex) { |
| // This is expected. |
| } |
| try { |
| byte[] aad = new byte[] {1, 2, 3}; |
| byte[] unused = eax.decrypt(null, aad); |
| fail("Decrypting a null ciphertext should fail"); |
| } catch (NullPointerException ex) { |
| // This is expected. |
| } |
| try { |
| byte[] unused = eax.decrypt(null, null); |
| fail("Decrypting a null ciphertext should fail"); |
| } catch (NullPointerException ex) { |
| // This is expected. |
| } |
| } |
| |
| @Test |
| public void testEmptyAssociatedData() throws Exception { |
| byte[] aad = new byte[0]; |
| byte[] key = Random.randBytes(KEY_SIZE); |
| AesEaxJce eax = new AesEaxJce(key, IV_SIZE); |
| for (int messageSize = 0; messageSize < 75; messageSize++) { |
| byte[] message = Random.randBytes(messageSize); |
| { // encrypting with aad as a 0-length array |
| byte[] ciphertext = eax.encrypt(message, aad); |
| byte[] decrypted = eax.decrypt(ciphertext, aad); |
| assertArrayEquals(message, decrypted); |
| byte[] decrypted2 = eax.decrypt(ciphertext, null); |
| assertArrayEquals(message, decrypted2); |
| try { |
| byte[] badAad = new byte[] {1, 2, 3}; |
| byte[] unused = eax.decrypt(ciphertext, badAad); |
| fail("Decrypting with modified aad should fail"); |
| } catch (AEADBadTagException ex) { |
| // This is expected. |
| } |
| } |
| { // encrypting with aad equal to null |
| byte[] ciphertext = eax.encrypt(message, null); |
| byte[] decrypted = eax.decrypt(ciphertext, aad); |
| assertArrayEquals(message, decrypted); |
| byte[] decrypted2 = eax.decrypt(ciphertext, null); |
| assertArrayEquals(message, decrypted2); |
| try { |
| byte[] badAad = new byte[] {1, 2, 3}; |
| byte[] unused = eax.decrypt(ciphertext, badAad); |
| fail("Decrypting with modified aad should fail"); |
| } catch (AEADBadTagException ex) { |
| // This is expected. |
| } |
| } |
| } |
| } |
| |
| } |