Android数据加密之Aes加密

  private final static String HEX = "0123456789ABCDEF";
  private static final String CBC_PKCS5_PADDING = "AES/CBC/PKCS5Padding";//AES是加密方式 CBC是工作模式 PKCS5Padding是填充模式
  private static final String AES = "AES";//AES 加密
  private static final String SHA1PRNG="SHA1PRNG";//// SHA1PRNG 强随机种子算法, 要区别4.2以上版本的调用方法

  /*
   * 生成随机数，可以当做动态的密钥 加密和解密的密钥必须一致，不然将不能解密
   */
  public static String generateKey() {
    try {
      SecureRandom localSecureRandom = SecureRandom.getInstance(SHA1PRNG);
      byte[] bytes_key = new byte[20];
      localSecureRandom.nextBytes(bytes_key);
      String str_key = toHex(bytes_key);
      return str_key;
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }

  // 对密钥进行处理
  private static byte[] getRawKey(byte[] seed) throws Exception {
    KeyGenerator kgen = KeyGenerator.getInstance(AES);
    //for android
    SecureRandom sr = null;
    // 在4.2以上版本中，SecureRandom获取方式发生了改变
    if (android.os.Build.VERSION.SDK_INT >= 17) {
      sr = SecureRandom.getInstance(SHA1PRNG, "Crypto");
    } else {
      sr = SecureRandom.getInstance(SHA1PRNG);
    }
    // for Java
    // secureRandom = SecureRandom.getInstance(SHA1PRNG);
    sr.setSeed(seed);
    kgen.init(128, sr); //256 bits or 128 bits,192bits
    //AES中128位密钥版本有10个加密循环，192比特密钥版本有12个加密循环，256比特密钥版本则有14个加密循环。
    SecretKey skey = kgen.generateKey();
    byte[] raw = skey.getEncoded();
    return raw;
  }

/*
   * 加密
   */
  public static String encrypt(String key, String cleartext) {
    if (TextUtils.isEmpty(cleartext)) {
      return cleartext;
    }
    try {
      byte[] result = encrypt(key, cleartext.getBytes());
      return Base64Encoder.encode(result);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }

  /*
  * 加密
  */
  private static byte[] encrypt(String key, byte[] clear) throws Exception {
    byte[] raw = getRawKey(key.getBytes());
    SecretKeySpec skeySpec = new SecretKeySpec(raw, AES);
    Cipher cipher = Cipher.getInstance(CBC_PKCS5_PADDING);
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec, new IvParameterSpec(new byte[cipher.getBlockSize()]));
    byte[] encrypted = cipher.doFinal(clear);
    return encrypted;
  }

  /*
   * 解密
   */
  public static String decrypt(String key, String encrypted) {
    if (TextUtils.isEmpty(encrypted)) {
      return encrypted;
    }
    try {
      byte[] enc = Base64Decoder.decodeToBytes(encrypted);
      byte[] result = decrypt(key, enc);
      return new String(result);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }

  /*
   * 解密
   */
  private static byte[] decrypt(String key, byte[] encrypted) throws Exception {
    byte[] raw = getRawKey(key.getBytes());
    SecretKeySpec skeySpec = new SecretKeySpec(raw, AES);
    Cipher cipher = Cipher.getInstance(CBC_PKCS5_PADDING);
    cipher.init(Cipher.DECRYPT_MODE, skeySpec, new IvParameterSpec(new byte[cipher.getBlockSize()]));
    byte[] decrypted = cipher.doFinal(encrypted);
    return decrypted;
  }

 //二进制转字符
  public static String toHex(byte[] buf) {
    if (buf == null)
      return "";
    StringBuffer result = new StringBuffer(2 * buf.length);
    for (int i = 0; i < buf.length; i++) {
      appendHex(result, buf[i]);
    }
    return result.toString();
  }

  private static void appendHex(StringBuffer sb, byte b) {
    sb.append(HEX.charAt((b >> 4) & 0x0f)).append(HEX.charAt(b & 0x0f));
  }

 List<Person> personList = new ArrayList<>();
    int testMaxCount = 1000;//测试的最大数据条数
    //添加测试数据
    for (int i = 0; i < testMaxCount; i++) {
      Person person = new Person();
      person.setAge(i);
      person.setName(String.valueOf(i));
      personList.add(person);
    }
    //FastJson生成json数据
    String jsonData = JsonUtils.objectToJsonForFastJson(personList);
    Log.e("MainActivity", "AES加密前json数据 ---->" + jsonData);
    Log.e("MainActivity", "AES加密前json数据长度 ---->" + jsonData.length());

    //生成一个动态key
    String secretKey = AesUtils.generateKey();
    Log.e("MainActivity", "AES动态secretKey ---->" + secretKey);

    //AES加密
    long start = System.currentTimeMillis();
    String encryStr = AesUtils.encrypt(secretKey, jsonData);
    long end = System.currentTimeMillis();
    Log.e("MainActivity", "AES加密耗时 cost time---->" + (end - start));
    Log.e("MainActivity", "AES加密后json数据 ---->" + encryStr);
    Log.e("MainActivity", "AES加密后json数据长度 ---->" + encryStr.length());

    //AES解密
    start = System.currentTimeMillis();
    String decryStr = AesUtils.decrypt(secretKey, encryStr);
    end = System.currentTimeMillis();
    Log.e("MainActivity", "AES解密耗时 cost time---->" + (end - start));
    Log.e("MainActivity", "AES解密后json数据 ---->" + decryStr);