Simple test vectors for XSalsa20/Poly1305

Test vectors taken from NaCl paper.

briar-tests/src/org/briarproject/crypto/XSalsa20Poly1305ACTest.java

+package org.briarproject.crypto;
+
+import org.briarproject.BriarTestCase;
+import org.briarproject.api.crypto.SecretKey;
+import org.briarproject.util.StringUtils;
+import org.junit.Test;
+
+import java.security.GeneralSecurityException;
+
+import static org.junit.Assert.assertArrayEquals;
+
+public class XSalsa20Poly1305ACTest extends BriarTestCase {
+
+	// Test vectors from the NaCl paper
+	// http://cr.yp.to/highspeed/naclcrypto-20090310.pdf
+	private static final byte[] TEST_KEY = StringUtils.fromHexString(
+			"1b27556473e985d462cd51197a9a46c76009549eac6474f206c4ee0844f68389");
+	private static final byte[] TEST_IV = StringUtils.fromHexString(
+			"69696ee955b62b73cd62bda875fc73d68219e0036b7a0b37");
+	private static final byte[] TEST_PLAINTEXT = StringUtils.fromHexString(
+					"be075fc53c81f2d5cf141316" +
+					"ebeb0c7b5228c52a4c62cbd4" +
+					"4b66849b64244ffce5ecbaaf" +
+					"33bd751a1ac728d45e6c6129" +
+					"6cdc3c01233561f41db66cce" +
+					"314adb310e3be8250c46f06d" +
+					"ceea3a7fa1348057e2f6556a" +
+					"d6b1318a024a838f21af1fde" +
+					"048977eb48f59ffd4924ca1c" +
+					"60902e52f0a089bc76897040" +
+					"e082f937763848645e0705");
+	private static final byte[] TEST_CIPHERTEXT = StringUtils.fromHexString(
+					"f3ffc7703f9400e52a7dfb4b" +
+					"3d3305d98e993b9f48681273" +
+					"c29650ba32fc76ce48332ea7" +
+					"164d96a4476fb8c531a1186a" +
+					"c0dfc17c98dce87b4da7f011" +
+					"ec48c97271d2c20f9b928fe2" +
+					"270d6fb863d51738b48eeee3" +
+					"14a7cc8ab932164548e526ae" +
+					"90224368517acfeabd6bb373" +
+					"2bc0e9da99832b61ca01b6de" +
+					"56244a9e88d5f9b37973f622" +
+					"a43d14a6599b1f654cb45a74" +
+					"e355a5");
+
+	@Test
+	public void testEncrypt() throws Exception {
+		SecretKey k = new SecretKey(TEST_KEY);
+		AuthenticatedCipher cipher = new XSalsa20Poly1305AC();
+		cipher.init(true, k, TEST_IV);
+		byte[] output = new byte[TEST_PLAINTEXT.length + cipher.getMacBytes()];
+		cipher.process(TEST_PLAINTEXT, 0, TEST_PLAINTEXT.length, output, 0);
+		assertArrayEquals(TEST_CIPHERTEXT, output);
+	}
+
+	@Test
+	public void testDecrypt() throws Exception {
+		SecretKey k = new SecretKey(TEST_KEY);
+		AuthenticatedCipher cipher = new XSalsa20Poly1305AC();
+		cipher.init(false, k, TEST_IV);
+		byte[] output = new byte[TEST_CIPHERTEXT.length - cipher.getMacBytes()];
+		cipher.process(TEST_CIPHERTEXT, 0, TEST_CIPHERTEXT.length, output, 0);
+		assertArrayEquals(TEST_PLAINTEXT, output);
+	}
+
+	@Test(expected = GeneralSecurityException.class)
+	public void testDecryptFailsWithShortInput() throws Exception {
+		SecretKey k = new SecretKey(TEST_KEY);
+		AuthenticatedCipher cipher = new XSalsa20Poly1305AC();
+		cipher.init(false, k, TEST_IV);
+		byte[] input = new byte[8];
+		System.arraycopy(TEST_CIPHERTEXT, 0, input, 0, 8);
+		byte[] output = new byte[TEST_CIPHERTEXT.length - cipher.getMacBytes()];
+		cipher.process(input, 0, input.length, output, 0);
+	}
+
+	@Test(expected = GeneralSecurityException.class)
+	public void testDecryptFailsWithAlteredCiphertext() throws Exception {
+		SecretKey k = new SecretKey(TEST_KEY);
+		AuthenticatedCipher cipher = new XSalsa20Poly1305AC();
+		cipher.init(false, k, TEST_IV);
+		byte[] input = new byte[TEST_CIPHERTEXT.length];
+		System.arraycopy(TEST_CIPHERTEXT, 0, input, 0, TEST_CIPHERTEXT.length);
+		input[TEST_CIPHERTEXT.length - cipher.getMacBytes()] = 42;
+		byte[] output = new byte[TEST_CIPHERTEXT.length - cipher.getMacBytes()];
+		cipher.process(input, 0, input.length, output, 0);
+	}
+}