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

import org.apache.commons.codec.binary.Base64;

public class MsgDigestDemo{
 public static void main(String args[]) throws NoSuchAlgorithmException, UnsupportedEncodingException {
  String msg = "Hello World!";

  MessageDigest md5Digest = MessageDigest.getInstance("MD5");
  // 更新要計(jì)算的內(nèi)容
  md5Digest.update(msg.getBytes());
  // 完成哈希計(jì)算，得到摘要
  byte[] md5Encoded = md5Digest.digest();

  MessageDigest shaDigest = MessageDigest.getInstance("SHA");
  // 更新要計(jì)算的內(nèi)容
  shaDigest.update(msg.getBytes());
  // 完成哈希計(jì)算，得到摘要
  byte[] shaEncoded = shaDigest.digest();

  System.out.println("原文: " + msg);
  System.out.println("MD5摘要: " + Base64.encodeBase64URLSafeString(md5Encoded));
  System.out.println("SHA摘要: " + Base64.encodeBase64URLSafeString(shaEncoded));
 }
}

importjavax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;

public class HmacCoder{
 /**
  * JDK支持HmacMD5, HmacSHA1,HmacSHA256, HmacSHA384, HmacSHA512
  */
 public enum HmacTypeEn {
  HmacMD5, HmacSHA1, HmacSHA256, HmacSHA384, HmacSHA512;
 }

 public static byte[] encode(byte[] plaintext, byte[] secretKey, HmacTypeEn type) throwsException {
  SecretKeySpec keySpec = new SecretKeySpec(secretKey, type.name());
  Mac mac = Mac.getInstance(keySpec.getAlgorithm());
  mac.init(keySpec);
  return mac.doFinal(plaintext);
 }

 public static void main(String[] args) throws Exception {
  String msg = "Hello World!";
  byte[] secretKey = "Secret_Key".getBytes("UTF8");
  byte[] digest = HmacCoder.encode(msg.getBytes(), secretKey, HmacTypeEn.HmacSHA256);
  System.out.println("原文: " + msg);
  System.out.println("摘要: " + Base64.encodeBase64URLSafeString(digest));
 }
}

importjava.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import org.apache.commons.codec.binary.Base64;

public class DsaCoder{
 public static final String KEY_ALGORITHM = "DSA";

 public enum DsaTypeEn {
  MD5withDSA, SHA1withDSA
 }

 /**
  * DSA密鑰長(zhǎng)度默認(rèn)1024位。 密鑰長(zhǎng)度必須是64的整數(shù)倍，范圍在512~1024之間
  */
 private static final int KEY_SIZE = 1024;

 private KeyPair keyPair;

 public DsaCoder() throws Exception {
  keyPair = initKey();
 }

 public byte[] signature(byte[] data, byte[] privateKey) throws Exception {
  PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKey);
  KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
  PrivateKey key =keyFactory.generatePrivate(keySpec);

  Signature signature = Signature.getInstance(DsaTypeEn.SHA1withDSA.name());
  signature.initSign(key);
  signature.update(data);
  return signature.sign();
 }

 public boolean verify(byte[] data, byte[] publicKey, byte[] sign) throws Exception {
  X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKey);
  KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
  PublicKey key =keyFactory.generatePublic(keySpec);

  Signature signature = Signature.getInstance(DsaTypeEn.SHA1withDSA.name());
  signature.initVerify(key);
  signature.update(data);
  return signature.verify(sign);
 }

 private KeyPair initKey() throws Exception {
  // 初始化密鑰對(duì)生成器
  KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
  // 實(shí)例化密鑰對(duì)生成器
  keyPairGen.initialize(KEY_SIZE);
  // 實(shí)例化密鑰對(duì)
  return keyPairGen.genKeyPair();
 }

 public byte[] getPublicKey() {
  return keyPair.getPublic().getEncoded();
 }

 public byte[] getPrivateKey() {
  return keyPair.getPrivate().getEncoded();
 }

 public static void main(String[] args) throws Exception {
  String msg = "Hello World";
  DsaCoder dsa = new DsaCoder();
  byte[] sign = dsa.signature(msg.getBytes(), dsa.getPrivateKey());
  boolean flag = dsa.verify(msg.getBytes(), dsa.getPublicKey(), sign);
  String result = flag ? "數(shù)字簽名匹配" : "數(shù)字簽名不匹配";
  System.out.println("數(shù)字簽名：" + Base64.encodeBase64URLSafeString(sign));
  System.out.println("驗(yàn)證結(jié)果：" + result);
 }
}