/*
 * Copyright 2010 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.gwt.emultest.java.security;

import com.google.gwt.emultest.java.util.EmulTestBase;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;

/**
 * Tests the message digest implementations.
 */
public class MessageDigestTest extends EmulTestBase {

  /**
   * Pairs of strings: test data, then MD5 hash.
   */
  private static String[] md5TestData = new String[] {
      "",
      "d41d8cd98f00b204e9800998ecf8427e",

      "a",
      "0cc175b9c0f1b6a831c399e269772661",

      "abc",
      "900150983cd24fb0d6963f7d28e17f72",

      "message digest",
      "f96b697d7cb7938d525a2f31aaf161d0",

      "abcdefghijklmnopqrstuvwxyz",
      "c3fcd3d76192e4007dfb496cca67e13b",

      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
      "d174ab98d277d9f5a5611c2c9f419d9f",

      "12345678901234567890123456789012345678901234567890123456789012345678901234567890",
      "57edf4a22be3c955ac49da2e2107b67a",

      "s nine o'clock at night upon the second of August--the mostterrible August in "
          + "the history of the world. One might have thoughtalready that God's curse "
          + "hung heavy over a degenerate world, for therewas an awesome hush and a "
          + "feeling of vague expectancy in the sultry andstagnant air. The sun had "
          + "long set, but one blood-red gash like anopen wound lay low in the distant "
          + "west. Above, the stars were shiningbrightly, and below, the lights of the "
          + "shipping glimmered in the bay.The two famous Germans stood beside the stone "
          + "parapet of the gardenwalk, with the long, low, heavily gabled house behind "
          + "them, and theylooked down upon the broad sweep of the beach at the foot of "
          + "the greatchalk cliff in which Von Bork, like some wandering eagle, had "
          + "perchedhimself four years before. They stood with their heads close "
          + "together,talking in low tones. From below the two glowing "
          + "ends oftheir cigars might have been the smouldering eyes of some "
          + "malignantfiend looking down in the darkness.A remarkable man this Von Bork--a "
          + "man who could hardly be matched amongall the devoted agents of the Kaiser. "
          + "It was his talents which hadfirst recommended him for the English mission, "
          + "the most importantmission of all, but since he had taken it over those "
          + "talents had becomemore and more manifest to the half-dozen people in the "
          + "world who werereally in touch with the truth. One of these was his "
          + "presentcompanion, Baron Von Herling, the chief secretary of the legation,whose "
          + "huge 100-horse-power Benz car was blocking the country lane as itwaited to "
          + "waft its owner back to London.'So far as I can judge the trend of events, you "
          + "will probably be backin Berlin within the week,' the secretary was saying. "
          + "'When you getthere, my dear Von Bork, I think you will be surprised at the "
          + "welcomeyou will receive. I happen to know what is thought in the "
          + "highestquarters of your work in this country.' He was a huge man, "
          + "thesecretary, deep, broad, and tall, with",
      "e4ab6d550fe9878dd9b2c83648e1a190",
  };

  private String[] sha256TestData = new String[] {
      "",
      "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",

      "a",
      "ca978112ca1bbdcafac231b39a23dc4da786eff8147c4e72b9807785afee48bb",

      "abc",
      "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad",

      "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
      "248d6a61d20638b8e5c026930c3e6039a33ce45964ff2167f6ecedd419db06c1",

      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
      "db4bfcbd4da0cd85a60c3c37d3fbd8805c77f15fc6b1fdfe614ee0a7c8fdb4c0",

      "a1y28pfxfkrb3dc0ysjzkc4ef5510a8fleg5nf7ld911lgl7n4bv09em",
      "6ebf24d2f4ab987311418f72e5ddcb829bdd9f3e54593b6d22b14fb7fe639e4c",

      "The SHA (Secure Hash Algorithm) is one of a number of cryptographic hash functions."
      + " A cryptographic hash is like a signature for a text or a data file."
      + " SHA-256 algorithm generates an almost-unique, fixed size 256-bit (32-byte) hash."
      + " Hash is a one way function – it cannot be decrypted back. This makes it suitable for"
      + " password validation, challenge hash authentication, anti-tamper, digital signatures.",
      "d37e2b4fab26640551c69abc3bdf1c14534b215c7f3e1d44c0b65029c99147fb"
  };

  private static void assertDigest(String expected, MessageDigest md,
      String data) throws UnsupportedEncodingException {
    byte[] bytes = data.getBytes("UTF-8");
    byte[] digest = md.digest(bytes);
    assertEquals(expected, toHexString(digest));
  }

  private static void assertDigestByByte(String expected, MessageDigest md,
      String data) throws UnsupportedEncodingException {
    byte[] bytes = data.getBytes("UTF-8");
    for (int i = 0; i < bytes.length; ++i) {
      md.update(bytes[i]);
    }
    byte[] digest = md.digest();
    assertEquals(expected, toHexString(digest));
  }

  private static String toHexString(byte[] bytes) {
    StringBuilder buf = new StringBuilder();
    for (int i = 0; i < bytes.length; ++i) {
      String hex = Integer.toHexString(bytes[i] & 255);
      buf.append("00".substring(hex.length())).append(hex);
    }
    return buf.toString();
  }

  public void testMd5() throws Exception {
    MessageDigest md5 = MessageDigest.getInstance("MD5");
    for (int i = 0; i < md5TestData.length; i += 2) {
      assertDigest(md5TestData[i + 1], md5, md5TestData[i]);
    }
  }

  public void testMd5ByBytes() throws Exception {
    MessageDigest md5 = MessageDigest.getInstance("MD5");
    for (int i = 0; i < md5TestData.length; i += 2) {
      assertDigestByByte(md5TestData[i + 1], md5, md5TestData[i]);
    }
  }

  public void testSHA256() throws Exception {
    MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
    for (int i = 0; i < sha256TestData.length; i += 2) {
      assertDigest(sha256TestData[i + 1], sha256, sha256TestData[i]);
    }
  }

  public void testSHA256ByBytes() throws Exception {
    MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
    for (int i = 0; i < sha256TestData.length; i += 2) {
      assertDigestByByte(sha256TestData[i + 1], sha256, sha256TestData[i]);
    }
  }
}