转自： http://comtu.github.io/blog/2014/12/01/Java_security.html

目录:

Base64
消息摘要算法
  MD
  SHA
  MAC
对称加密算法
  DES
  3DES
  AES
  PBE
非对称加密算法
  DH
  RSA
  ElGamal
数字签名算法
  RSA
  DSA
  ECDSA
其它算法
  IDEA
  CRC

Base64

public static void jdkBase64(String msg) {
    try {
      BASE64Encoder encoder = new BASE64Encoder();
      String encode = encoder.encode(msg.getBytes());
      System.out.println("encode:" + encode);
      
      BASE64Decoder decoder = new BASE64Decoder();
      byte[] b = decoder.decodeBuffer(encode);
      System.out.println("decoder:" + new String(b));
    } catch (Exception e) {
    }
  }

  public static void commonsCodesBase64(String msg) {
    byte[] encodeBytes = org.apache.commons.codec.binary.Base64.encodeBase64(msg.getBytes());
    System.out.println("encode:" + new String(encodeBytes));

    byte[] decodeBytes = org.apache.commons.codec.binary.Base64.decodeBase64(encodeBytes);
    System.out.println("decode:" + new String(decodeBytes));
  }
  
  public static void bouncyCastleBase64(String msg) {
    byte[] encodeBytes = org.bouncycastle.util.encoders.Base64.encode(msg.getBytes());
    System.out.println("encode:" + new String(encodeBytes));
    
    byte[] decodeBytes = org.bouncycastle.util.encoders.Base64.decode(encodeBytes);
    System.out.println("decode:" + new String(decodeBytes));
  }

消息摘要算法 – MD

 算法:
 MD2  实现方:JDK
 MD4  实现方:BouncyCastle 简称BC
 MD5  实现方:JDK

public static void jdkMD2(String msg) {
    try {
      MessageDigest md = MessageDigest.getInstance("MD2");
      byte[] md2Bytes = md.digest(msg.getBytes());
      System.out.println("JDK MD2:" + org.apache.commons.codec.binary.Hex.encodeHexString(md2Bytes));
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  public static void jdkMD5(String msg) {
    try {
      MessageDigest md = MessageDigest.getInstance("MD5");
      byte[] md5Bytes = md.digest(msg.getBytes());
      System.out.println("JDK MD5:" + org.apache.commons.codec.binary.Hex.encodeHexString(md5Bytes));
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  // BouncyCastle
  public static void bcMD4(String msg) {
    try {
      Security.addProvider(new BouncyCastleProvider());// 为JDK设置算法
      MessageDigest md = MessageDigest.getInstance("MD4");
      byte[] md4Bytes = md.digest(msg.getBytes());
      System.out.println("JDK MD5:" + org.apache.commons.codec.binary.Hex.encodeHexString(md4Bytes));
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    }

    Digest digest = new MD4Digest();
    digest.update(msg.getBytes(), 0, msg.getBytes().length);
    byte[] md4Byte = new byte[digest.getDigestSize()];
    digest.doFinal(md4Byte, 0);
    System.out.println("BC MD4: " + org.bouncycastle.util.encoders.Hex.toHexString(md4Byte));
  }

  // BouncyCastle
  public static void bcMD5(String msg) {
    Digest digest = new MD5Digest();
    digest.update(msg.getBytes(), 0, msg.getBytes().length);
    byte[] md5Byte = new byte[digest.getDigestSize()];
    digest.doFinal(md5Byte, 0);
    System.out.println("BC MD5: " + org.bouncycastle.util.encoders.Hex.toHexString(md5Byte));
  }
  
  //commons codec
  public static void ccMD5(String msg){
    System.out.println("CC MD5:"+DigestUtils.md5Hex(msg.getBytes()));
  }
  //commons codec
  public static void ccMD2(String msg){
    System.out.println("CC MD2:"+DigestUtils.md2Hex(msg.getBytes()));
  }

  //-----------------
  public static final String MD5_TYPE_16 = "t_16";
  public static final String MD5_TYPE_32 = "T_32";

  public static String md5s(String plainText, String type) {
    try {
      MessageDigest md = MessageDigest.getInstance("MD5");
      md.update(plainText.getBytes());
      byte b[] = md.digest();

      int i;

      StringBuffer buf = new StringBuffer("");
      for (int offset = 0; offset < b.length; offset++) {
        i = b[offset];
        if (i < 0)
          i += 256;
        if (i < 16)
          buf.append("0");
        buf.append(Integer.toHexString(i));
      }
      String str = buf.toString();

      if (type.equals(MD5_TYPE_16)) {
        str = str.substring(8, 24);