单例模式RSA工具类

  1 package com.founder.centerbusiness.common.utils;
  2 
  3 import org.apache.commons.codec.binary.Base64;
  4 import javax.crypto.Cipher;
  5 import java.security.KeyFactory;
  6 import java.security.KeyPair;
  7 import java.security.KeyPairGenerator;
  8 import java.security.NoSuchAlgorithmException;
  9 import java.security.SecureRandom;
 10 import java.security.interfaces.RSAPrivateKey;
 11 import java.security.interfaces.RSAPublicKey;
 12 import java.security.spec.PKCS8EncodedKeySpec;
 13 import java.security.spec.X509EncodedKeySpec;
 14 import java.util.HashMap;
 15 import java.util.Map;
 16 import java.util.concurrent.locks.ReentrantLock;
 17 
 18 //Author:guanghe
 19 public class RSAEncryptUtil {
 20 
 21     //单例
 22     private static Map<Integer, String> keyMap;
 23     private static ReentrantLock lock = new ReentrantLock();
 24 
 25     //生成密钥对
 26     public static void genKeyPair() throws NoSuchAlgorithmException {
 27         if(keyMap == null) {
 28             lock.lock();
 29             if(keyMap == null) {
 30                 // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
 31                 KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
 32                 // 初始化密钥对生成器，密钥大小为512-1024位
 33                 keyPairGen.initialize(512,new SecureRandom());
 34                 // 生成一个密钥对，保存在keyPair中
 35                 KeyPair keyPair = keyPairGen.generateKeyPair();
 36                 RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();   // 得到私钥
 37                 RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();  // 得到公钥
 38                 String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
 39                 // 得到私钥字符串
 40                 String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
 41                 // 将公钥和私钥保存到Map
 42                 keyMap = new HashMap<>();
 43                 keyMap.put(0,publicKeyString);
 44                 keyMap.put(1,privateKeyString);
 45             }
 46             lock.unlock();
 47         }
 48     }
 49 
 50     //获取公钥
 51     public static String getPublicKey() throws NoSuchAlgorithmException{
 52         if(keyMap == null) genKeyPair();
 53         return keyMap.get(0);
 54     }
 55 
 56     //获取私钥
 57     public static String getPrivateKey() throws NoSuchAlgorithmException{
 58         if(keyMap == null) genKeyPair();
 59         return keyMap.get(1);
 60     }
 61 
 62     //加密
 63     public static String encrypt(String str) throws Exception {
 64         return encrypt(str, getPrivateKey());
 65     }
 66     
 67     //加密
 68     public static String encrypt(String str, String publicKey ) throws Exception {
 69         //base64编码的公钥
 70         byte[] decoded = Base64.decodeBase64(publicKey);
 71         RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
 72         //RSA加密
 73         Cipher cipher = Cipher.getInstance("RSA");
 74         cipher.init(Cipher.ENCRYPT_MODE, pubKey);
 75         return Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
 76     }
 77 
 78     //解密
 79     public static String decrypt(String str) throws Exception {
 80         return decrypt(str, getPrivateKey());
 81     }
 82     
 83     //解密
 84     public static String decrypt(String str, String privateKey) throws Exception {
 85         //64位解码加密后的字符串
 86         byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
 87         //base64编码的私钥
 88         byte[] decoded = Base64.decodeBase64(privateKey);
 89         RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
 90         //RSA解密
 91         Cipher cipher = Cipher.getInstance("RSA");
 92         cipher.init(Cipher.DECRYPT_MODE, priKey);
 93         return new String(cipher.doFinal(inputByte));
 94     }
 95 
 96     public static void main(String[] args) throws Exception {
 97         //加密字符串
 98         String message = "guanghe";
 99         System.out.println("随机生成的公钥为:" + getPublicKey());
100         System.out.println("随机生成的私钥为:" + getPrivateKey());
101         String messageEn = encrypt(message,getPublicKey());
102         System.out.println(message + "	加密后的字符串为:" + messageEn);
103         String messageDe = decrypt(messageEn,getPrivateKey());
104         System.out.println("还原后的字符串为:" + messageDe);
105     }
106 
107 }