java中常用的加密算法使用

Encryption.java

package com.hunt.utils;

import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;

/**
 * 2015-01-13
 * 
 * @author cylan-hunt
 * 
 */
public class Encryption {
	/**
	 * 
	 * @author cylan-hunt MD5 return String
	 * 
	 */
	private static final char HEXDIGITS[] = { '0', '1', '2', '3', '4', '5',
			'6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

	public static class EncrypMD5 {

		public static String encryptS(String info)
				throws NoSuchAlgorithmException {
			MessageDigest md5 = MessageDigest.getInstance("MD5");
			byte[] srcBytes = info.getBytes();
			// 使用srcBytes更新摘要
			md5.update(srcBytes);
			// 完成哈希计算，得到result
			byte[] resultBytes = md5.digest();
			char str[] = new char[16 * 2];
			int k = 0;
			for (int i = 0; i < 16; i++) {
				byte byte0 = resultBytes[i];
				str[k++] = HEXDIGITS[byte0 >>> 4 & 0xf];
				str[k++] = HEXDIGITS[byte0 & 0xf];
			}
			return new String(str);
		}

		/**
		 * 
		 * @param info
		 * @return encrypt byte[]
		 * @throws NoSuchAlgorithmException
		 */
		public static byte[] encryptB(String info)
				throws NoSuchAlgorithmException {
			MessageDigest md5 = MessageDigest.getInstance("MD5");
			byte[] srcBytes = info.getBytes();
			// 使用srcBytes更新摘要
			md5.update(srcBytes);
			// 完成哈希计算，得到result
			byte[] resultBytes = md5.digest();

			return resultBytes;
		}
	}

	public static class EncrypRSA {

		/**
		 * 加密
		 * 
		 * @param publicKey
		 * @param srcBytes
		 * @return
		 * @throws NoSuchAlgorithmException
		 * @throws NoSuchPaddingException
		 * @throws InvalidKeyException
		 * @throws IllegalBlockSizeException
		 * @throws BadPaddingException
		 */
		protected static byte[] encryptB(RSAPublicKey publicKey, byte[] srcBytes)
				throws NoSuchAlgorithmException, NoSuchPaddingException,
				InvalidKeyException, IllegalBlockSizeException,
				BadPaddingException {
			if (publicKey != null) {
				// Cipher负责完成加密或解密工作，基于RSA
				Cipher cipher = Cipher.getInstance("RSA");
				// 根据公钥，对Cipher对象进行初始化
				cipher.init(Cipher.ENCRYPT_MODE, publicKey);
				byte[] resultBytes = cipher.doFinal(srcBytes);
				return resultBytes;
			}
			return null;
		}

		/**
		 * 解密
		 * 
		 * @param privateKey
		 * @param srcBytes
		 * @return
		 * @throws NoSuchAlgorithmException
		 * @throws NoSuchPaddingException
		 * @throws InvalidKeyException
		 * @throws IllegalBlockSizeException
		 * @throws BadPaddingException
		 */
		protected static byte[] decrypt(RSAPrivateKey privateKey,
				byte[] srcBytes) throws NoSuchAlgorithmException,
				NoSuchPaddingException, InvalidKeyException,
				IllegalBlockSizeException, BadPaddingException {
			if (privateKey != null) {
				// Cipher负责完成加密或解密工作，基于RSA
				Cipher cipher = Cipher.getInstance("RSA");
				// 根据公钥，对Cipher对象进行初始化
				cipher.init(Cipher.DECRYPT_MODE, privateKey);
				byte[] resultBytes = cipher.doFinal(srcBytes);
				return resultBytes;
			}
			return null;
		}

		/**
		 * @param args
		 * @throws NoSuchAlgorithmException
		 * @throws BadPaddingException
		 * @throws IllegalBlockSizeException
		 * @throws NoSuchPaddingException
		 * @throws InvalidKeyException
		 */
		// public static void main(String[] args) throws
		// NoSuchAlgorithmException,
		// InvalidKeyException, NoSuchPaddingException,
		// IllegalBlockSizeException, BadPaddingException {
		// EncrypRSA rsa = new EncrypRSA();
		// String msg = "郭德纲-精品相声";
		// // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
		// KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
		// // 初始化密钥对生成器，密钥大小为1024位
		// keyPairGen.initialize(1024);
		// // 生成一个密钥对，保存在keyPair中
		// KeyPair keyPair = keyPairGen.generateKeyPair();
		// // 得到私钥
		// RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
		// // 得到公钥
		// RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
		//
		// // 用公钥加密
		// byte[] srcBytes = msg.getBytes();
		// byte[] resultBytes = rsa.encrypt(publicKey, srcBytes);
		//
		// // 用私钥解密
		// byte[] decBytes = rsa.decrypt(privateKey, resultBytes);
		//
		// System.out.println("明文是:" + msg);
		// System.out.println("加密后是:" + new String(resultBytes));
		// System.out.println("解密后是:" + new String(decBytes));
	}

	public static class EncrypSHA {

		public static byte[] eccryptB(String info)
				throws NoSuchAlgorithmException {
			MessageDigest md5 = MessageDigest.getInstance("SHA");
			byte[] srcBytes = info.getBytes();
			// 使用srcBytes更新摘要
			md5.update(srcBytes);
			// 完成哈希计算，得到result
			byte[] resultBytes = md5.digest();
			return resultBytes;
		}

		/**
		 * 
		 * @param info
		 * @return String
		 * @throws NoSuchAlgorithmException
		 */
		public static String eccryptS(String info)
				throws NoSuchAlgorithmException {
			MessageDigest md5 = MessageDigest.getInstance("SHA");
			byte[] srcBytes = info.getBytes();
			// 使用srcBytes更新摘要
			md5.update(srcBytes);
			// 完成哈希计算，得到result
			byte[] resultBytes = md5.digest();
			char str[] = new char[16 * 2];
			int k = 0;
			for (int i = 0; i < 16; i++) {
				byte byte0 = resultBytes[i];
				str[k++] = HEXDIGITS[byte0 >>> 4 & 0xf];
				str[k++] = HEXDIGITS[byte0 & 0xf];
			}
			return new String(str);
		}

	}
}