公钥加密算法，也就是 非对称加密算法，这种算法加密和解密的密码不一样，一个是公钥，另一个是私钥：
公钥和私钥是相对的，两者本身并没有规定哪一个必须是公钥或私钥。
代码如下
package com.cxy.template.controller.keyTools;
import java.util.Base64;
import javax.crypto.Cipher;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
/**
* Java RSA 加密工具类
*
*/
public class RSAUtils {
/**
* 密钥长度 于原文长度对应 以及越长速度越慢
*/
private final static int KEY_SIZE = 1024;
/**
* 用于封装随机产生的公钥与私钥
*/
private static Map<Integer, String> keyMap = new HashMap<Integer, String>();
/**
* 随机生成密钥对
*/
public static void genKeyPair() throws NoSuchAlgorithmException {
// 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
keyPairGen.initialize(KEY_SIZE, new SecureRandom());
// 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();
String publicKeyString = Base64.getEncoder().encodeToString(publicKey.getEncoded());
// 得到私钥字符串
String privateKeyString = Base64.getEncoder().encodeToString(privateKey.getEncoded());
// 将公钥和私钥保存到Map
//0表示公钥
keyMap.put(0, publicKeyString);
//1表示私钥
keyMap.put(1, privateKeyString);
}
/**
* RSA公钥加密
*
* @param str 加密字符串
* @param publicKey 公钥
* @return 密文
* @throws Exception 加密过程中的异常信息
*/
public static String encrypt(String str, String publicKey) throws Exception {
//base64编码的公钥
byte[] decoded = Base64.getDecoder().decode(publicKey);
RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
//RSA加密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
String outStr = Base64.getEncoder().encodeToString(cipher.doFinal(str.getBytes("UTF-8")));
return outStr;
}
/**
* RSA私钥解密
*
* @param str 加密字符串
* @param privateKey 私钥
* @return 明文
* @throws Exception 解密过程中的异常信息
*/
public static String decrypt(String str, String privateKey) throws Exception {
//64位解码加密后的字符串
byte[] inputByte = Base64.getDecoder().decode(str);
//base64编码的私钥
byte[] decoded = Base64.getDecoder().decode(privateKey);
RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
//RSA解密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, priKey);
String outStr = new String(cipher.doFinal(inputByte));
return outStr;
}
public static void main(String[] args) throws Exception {
long temp = System.currentTimeMillis();
//生成公钥和私钥
genKeyPair();
//加密字符串
System.out.println("公钥:" + keyMap.get(0));
System.out.println("私钥:" + keyMap.get(1));
System.out.println("生成密钥消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
//客户id + 授权时间 + 所用模块
String message = "4028138151b3cf300151b419df090007" + "2015-12-17 11:30:22" + "A01,A02";
System.out.println("原文:" + message);
temp = System.currentTimeMillis();
//通过原文，和公钥加密。
String messageEn = encrypt(message, keyMap.get(0));
System.out.println("密文:" + messageEn);
System.out.println("加密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
temp = System.currentTimeMillis();
//通过密文，和私钥解密。
String messageDe = decrypt(messageEn, keyMap.get(1));
System.out.println("解密:" + messageDe);
System.out.println("解密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
}
}
测试如下
公钥:MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCtI8/X2ayQNXsz6/HTJew8z86+aevsJJLNS5dT74/zUwfaOpouInMQLwhqLFvMoCIzw2CLdG7/hwx3HGlKTHDpaTCqnKu17NVOriI8o7lAgI6pK/L2M8kpkbAG88XBmH6aNbi94TS1/ljsS9jMNoEQvfLC2A/KUw9sopRg73gAawIDAQAB 私钥: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 生成密钥消耗时间:0.129秒 原文:4028138151b3cf300151b419df0900072015-12-17 11:30:22A01,A02 密文:DnNGSArBjHQ46uyP9aBBs/f+zGwbpM2suh39Imdqu1ebUyCdB6b1AYB8Y7snklttm++EQjrKO8B+06er0+bOJb8lXbHQrvDkFCbcp31TiCBeITZT8bWpHQfwVmutVYKCYGwuk2E5VXQfSySuh6ZsUX/M/3UfS9MvKbQB3d1dyJ8= 加密消耗时间:0.217秒 解密:4028138151b3cf300151b419df0900072015-12-17 11:30:22A01,A02 解密消耗时间:0.003秒 Process finished with exit code 0
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