加密、解密

关注1：http://hello-nick-xu.iteye.com/blog/2103775
关注2：http://hello-nick-xu.iteye.com/blog/2103781
package com.rock;

import java.io.IOException; 
import java.security.Key; 
import java.security.KeyPair; 
import java.security.KeyPairGenerator; 
import java.security.MessageDigest; 
import java.security.NoSuchAlgorithmException; 
import java.security.PrivateKey; 
import java.security.PublicKey; 
import java.security.SecureRandom; 
import java.security.Signature; 
 
import javax.crypto.Cipher; 
import javax.crypto.SecretKey; 
import javax.crypto.SecretKeyFactory; 
import javax.crypto.spec.DESKeySpec; 
 
import org.apache.commons.logging.Log; 
import org.apache.commons.logging.LogFactory; 
 
import sun.misc.BASE64Decoder; 
import sun.misc.BASE64Encoder;

public class EncryptUtil {
private static Log logger = LogFactory.getLog(EncryptUtil.class); 
   
    private static final int KEY_SIZE = 1024; 
    private static final String  MD5_ALGORITHM= "md5"; 
    private static final String  DES_ALGORITHM= "des"; 
    private static final String  RSA_ALGORITHM= "rsa"; 
    private static final String  SIGNATURE_ALGORITHM= "MD5withRSA"; 
     
    private static MessageDigest md5; 
    private static BASE64Encoder encoder; 
    private static BASE64Decoder decoder; 
    private static SecureRandom random; 
    private static KeyPair keyPair; 
     
    private EncryptUtil() { 
    } 
     
    static { 
        try { 
            md5 = MessageDigest.getInstance(MD5_ALGORITHM); 
             
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(RSA_ALGORITHM); 
            keyPairGenerator.initialize(KEY_SIZE); 
            keyPair = keyPairGenerator.generateKeyPair(); 
        } 
        catch (NoSuchAlgorithmException e) { 
            // Exception handler 
            logger.error(e); 
        } 
        encoder = new BASE64Encoder(); 
        decoder = new BASE64Decoder(); 
        random = new SecureRandom(); 
    } 
     
    /**
     * 功能简述: 使用md5进行单向加密.
     */ 
    public static String encryptMD5(String plainText) { 
        byte[] cipherData = md5.digest(plainText.getBytes()); 
        StringBuilder builder = new StringBuilder(); 
        for(byte cipher : cipherData) { 
            String toHexStr = Integer.toHexString(cipher & 0xff); 
            builder.append(toHexStr.length() == 1 ? "0" + toHexStr : toHexStr); 
        } 
        return builder.toString(); 
    } 
     
   
//    public static void main(String[] args) {
// System.out.println("=======>>MD5加密：   "+encryptMD5("xueshuanglong_198822"));
// //8ff95d3b0db752ac6d10b21bc05dec38
// }
   
   
    /**
     * 功能简述: 使用BASE64进行加密.
     * @param plainData 明文数据
     * @return 加密之后的文本内容
     */ 
    public static String encryptBASE64(byte[] plainData) { 
        return encoder.encode(plainData); 
    } 
     
//    public static void main(String[] args) {
//
//    System.out.println("=======>>BASE64加密：   "+encryptBASE64("xueshuanglong_198822".getBytes()));
//    //eHVlc2h1YW5nbG9uZ18xOTg4MjI=
// }
  
    /**
     * 功能简述: 使用BASE64进行解密.
     * @param cipherText 密文文本
     * @return 解密之后的数据
     */ 
    public static byte[] decryptBASE64(String cipherText) { 
        byte[] plainData = null; 
        try { 
            plainData =  decoder.decodeBuffer(cipherText); 
        } 
        catch (IOException e) { 
            // Exception handler 
            logger.error(e); 
        } 
        return plainData; 
    } 
    
//  public static void main(String[] args) {
//
// System.out.println("=======>>BASE64解密：   "+new String(decryptBASE64("eHVlc2h1YW5nbG9uZ18xOTg4MjI=")));
// //eHVlc2h1YW5nbG9uZ18xOTg4MjI=
//}
   
    /**
     * 功能简述: 使用DES算法进行加密.
     * @param plainData 明文数据
     * @param key   加密密钥
     * @return  
     */ 
    public static byte[] encryptDES(byte[] plainData, String key) { 
        return processCipher(plainData, createSecretKey(key), Cipher.ENCRYPT_MODE, DES_ALGORITHM); 
    } 
     
//    public static void main(String[] args) {
//    System.out.println("=======>>DES加密：   "+encryptBASE64(encryptDES("xueshuanglong_198822".getBytes(), "1234567890")));
//    //AW+L+c1d/zTRW0xFkA05Wft+S8LmvkCL
// }
    /**
     * 功能简述: 使用DES算法进行解密.
     * @param cipherData    密文数据
     * @param key   解密密钥
     * @return
     */ 
    public static byte[] decryptDES(byte[] cipherData, String key) { 
        return processCipher(cipherData, createSecretKey(key), Cipher.DECRYPT_MODE, DES_ALGORITHM); 
    } 
     
//    public static void main(String[] args) {
//    System.out.println("=======>>DES解密：   "+new String(decryptDES(decryptBASE64("AW+L+c1d/zTRW0xFkA05Wft+S8LmvkCL"),"1234567890")));
//   
// }
   
   
    /**
     * 功能简述: 根据key创建密钥SecretKey.
     * @param key 
     * @return
     */ 
    private static SecretKey createSecretKey(String key) { 
        SecretKey secretKey = null; 
        try { 
            DESKeySpec keySpec = new DESKeySpec(key.getBytes()); 
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES_ALGORITHM); 
            secretKey = keyFactory.generateSecret(keySpec); 
        } 
        catch (Exception e) { 
            // Exception handler 
            logger.error(e); 
        } 
        return secretKey; 
    } 
     
    /**
     * 功能简述: 加密/解密处理流程.
     * @param processData   待处理的数据
     * @param key   提供的密钥
     * @param opsMode   工作模式
     * @param algorithm   使用的算法
     * @return  
     */ 
    private static byte[] processCipher(byte[] processData, Key key, int opsMode, String algorithm) { 
        try{  
            Cipher cipher = Cipher.getInstance(algorithm); 
            cipher.init(opsMode, key, random); 
            return cipher.doFinal(processData); 
        } 
        catch (Exception e) { 
            // Exception handler 
            logger.error(e); 
        } 
        return null; 
    } 
     
    /**
     * 功能简述: 创建私钥，用于RSA非对称加密.
     * @return
     */ 
    public static PrivateKey createPrivateKey() { 
        return keyPair.getPrivate(); 
    } 
     
    /**
     * 功能简述: 创建公钥，用于RSA非对称加密.
     * @return
     */ 
    public static PublicKey createPublicKey() { 
        return keyPair.getPublic(); 
    } 
     
    /**
     * 功能简述: 使用RSA算法加密.
     * @param plainData 明文数据
     * @param key   密钥
     * @return
     */ 
    public static byte[] encryptRSA(byte[] plainData, Key key) { 
        return processCipher(plainData, key, Cipher.ENCRYPT_MODE, RSA_ALGORITHM); 
    } 
     
//    public static void main(String[] args) {
//   
//    System.out.println("=======>>RSA加密：   "+new BASE64Encoder().encode(encryptRSA("Hello , world !".getBytes(), createPrivateKey())));
// }
   
    /**
     * 功能简述: 使用RSA算法解密.
     * @param cipherData    密文数据
     * @param key   密钥
     * @return
     */ 
    public static byte[] decryptRSA(byte[] cipherData, Key key) { 
        return processCipher(cipherData, key, Cipher.DECRYPT_MODE, RSA_ALGORITHM); 
    } 
     
    public static void main(String[] args) {
    byte[] cipherData = encryptRSA("Hello , world !".getBytes(), createPrivateKey());
    System.out.println("=======>>RSA加密：   "+new BASE64Encoder().encode(cipherData));
    System.out.println("=======>>RSA解密：   "+new String(decryptRSA(cipherData, createPublicKey())));
    byte[] signData=createSignature(cipherData,createPrivateKey());
    System.out.println("=======>>使用私钥对加密数据创建数字签名：   "+new BASE64Encoder().encode(signData));
    System.out.println("=======>>使用公钥对数字签名进行验证：   "+verifySignature(cipherData,signData,createPublicKey()));
}
   
    /**
     * 功能简述: 使用私钥对加密数据创建数字签名.
     * @param cipherData     已经加密过的数据
     * @param privateKey    私钥
     * @return
     */ 
    public static byte[] createSignature(byte[] cipherData, PrivateKey privateKey) { 
        try { 
            Signature signature  = Signature.getInstance(SIGNATURE_ALGORITHM); 
            signature.initSign(privateKey); 
            signature.update(cipherData); 
            return signature.sign(); 
        } 
        catch (Exception e) { 
            // Exception handler 
            logger.error(e);  
        } 
        return null; 
    } 
     
    /**
     * 功能简述: 使用公钥对数字签名进行验证.
     * @param signData  数字签名
     * @param publicKey 公钥
     * @return
     */ 
    public static boolean verifySignature(byte[] cipherData, byte[] signData, PublicKey publicKey) { 
        try { 
            Signature signature  = Signature.getInstance(SIGNATURE_ALGORITHM); 
            signature.initVerify(publicKey); 
            signature.update(cipherData); 
            return signature.verify(signData); 
        } 
        catch (Exception e) { 
            // Exception handler 
            logger.error(e); 
        } 
        return false; 
    }
   
  
}