rsatool.java

java实例

package jct;


import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.security.Security;
import javax.crypto.Cipher;

/**
 * <p>封装同RSA非对称加密算法有关的方法，可用于数字签名，RSA加密解密</p>
 * @Copyright:WDSsoft
 * @ad:WDSsoft “企业多级数字签名系统”- 最佳的企业电子文档多级数字签名方案
 * @URL:www.wdssoft.com
 * @作者 吴东升 [e-mail] [e-mail]
 */

public class RSATool {

  public RSATool() {  }

  /**
   * 用一个已打包成byte[]形式的私钥加密数据，即数字签名
   * @param keyInByte 打包成byte[]的私钥
   * @param source 要签名的数据，一般应是数字摘要
   * @return 签名 byte[]
   */
  public static byte[] sign(byte[] keyInByte,byte[] source){
   try{
      PKCS8EncodedKeySpec priv_spec=new PKCS8EncodedKeySpec(keyInByte);
      KeyFactory mykeyFactory=KeyFactory.getInstance("RSA");
      PrivateKey privKey= mykeyFactory.generatePrivate(priv_spec);
      Signature sig=Signature.getInstance("SHA1withRSA");
      sig.initSign(privKey);
      sig.update(source);
      return sig.sign();
   }catch(Exception e){   return null;      }
  }
  /**
   * 验证数字签名
   * @param keyInByte 打包成byte[]形式的公钥
   * @param source 原文的数字摘要
   * @param sign 签名（对原文的数字摘要的签名）
   * @return 是否证实 boolean
   */
  public static boolean verify(byte[] keyInByte,byte[] source,byte[] sign){
        try{
          KeyFactory mykeyFactory=KeyFactory.getInstance("RSA");
          Signature sig=Signature.getInstance("SHA1withRSA");
          X509EncodedKeySpec pub_spec=new X509EncodedKeySpec(keyInByte);
          PublicKey pubKey=mykeyFactory.generatePublic(pub_spec);
          sig.initVerify(pubKey);
          sig.update(source);
          return sig.verify(sign);
        }catch(Exception e){
             return false;
           }
        }
  /**
   * 建立新的密钥对，返回打包的byte[]形式私钥和公钥
   * @return 包含打包成byte[]形式的私钥和公钥的object[],其中，object[0]为私钥byte[],object[1]为工要byte[]
   */
  public static Object[] giveRSAKeyPairInByte(){
        KeyPair newKeyPair=creatmyKey();
        if(newKeyPair==null)return null;
        Object[] re=new Object[2];
        if(newKeyPair!=null){
           PrivateKey priv=newKeyPair.getPrivate();
           byte[] b_priv = priv.getEncoded();
           PublicKey pub=newKeyPair.getPublic();
           byte[] b_pub=pub.getEncoded();
                   re[0]=b_priv;
                   re[1]=b_pub;
                   return re;
        }
        return null;
      }

    /**
         * 新建密钥对
         * @return KeyPair对象
         */
      public static KeyPair creatmyKey(){
            KeyPair myPair;
            long mySeed;
            mySeed=System.currentTimeMillis();
            try{
                  KeyPairGenerator keyGen=KeyPairGenerator.getInstance("RSA");
                  SecureRandom random=SecureRandom.getInstance("SHA1PRNG","SUN");
                  random.setSeed(mySeed);
                  keyGen.initialize(1024,random);
                  myPair=keyGen.generateKeyPair();
                  }catch(Exception e1){  return null;  }
             return myPair;
      }


/**
 * 使用RSA公钥加密数据
 * @param pubKeyInByte 打包的byte[]形式公钥
 * @param data 要加密的数据
 * @return 加密数据
 */
  public static byte[] encryptByRSA(byte[] pubKeyInByte,byte[] data){
    try{
          KeyFactory mykeyFactory=KeyFactory.getInstance("RSA");
          X509EncodedKeySpec pub_spec=new X509EncodedKeySpec(pubKeyInByte);
          PublicKey pubKey=mykeyFactory.generatePublic(pub_spec);
          Cipher cipher=Cipher.getInstance("RSA/ECB/PKCS1Padding");
          cipher.init(Cipher.ENCRYPT_MODE,pubKey);
          return cipher.doFinal(data);
    }catch(Exception e){  return null; }
  }
 /**
  * 用RSA私钥解密
  * @param privKeyInByte 私钥打包成byte[]形式
  * @param data 要解密的数据
  * @return 解密数据
  */
  public static byte[] decryptByRSA(byte[] privKeyInByte,byte[] data){
   try{
          PKCS8EncodedKeySpec priv_spec=new PKCS8EncodedKeySpec(privKeyInByte);
          KeyFactory mykeyFactory=KeyFactory.getInstance("RSA");
          PrivateKey privKey= mykeyFactory.generatePrivate(priv_spec);
          Cipher cipher=Cipher.getInstance("RSA/ECB/PKCS1Padding");
          cipher.init(Cipher.DECRYPT_MODE,privKey);
          return cipher.doFinal(data);
        }catch(Exception e){  return null;     }

  }
/**
 *测试
 */
   public static void main(String[] args) {
         try{

               Object[]  v=giveRSAKeyPairInByte();
               byte[] source=Digest.MdigestSHA("haha");
               byte[] sign=sign((byte[])v[0],source);
               boolean yes=verify((byte[])v[1],source,sign);
               if(yes) System.out.print("verify\n");
               }catch(Exception e){e.printStackTrace();}

   }
}