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java RSAUtils 加密工具类操作

作者：after95　　发布时间：2023-05-04 19:08:32　

标签：java,RSAUtils,加密,工具类

1.RSA加密算法是一种非对称加密算法。在公开密钥加密和电子商业中RSA被广泛使用。RSA公开密钥密码体制。所谓的公开密钥密码体制就是使用不同的加密密钥与解密密钥，是一种“由已知加密密钥推导出解密密钥在计算上是不可行的”密码体制。在公开密钥密码体制中，加密密钥（即公开密钥）PK是公开信息，而解密密钥（即秘密密钥）SK是需要保密的。加密算法E和解密算法D也都是公开的。虽然解密密钥SK是由公开密钥PK决定的，但却不能根据PK计算出SK。

2.本工具类涉及到BASE64编码，所以先展示出BASE64Utils：

package com.example.springboottest.common.util;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
import java.security.MessageDigest;

/**
* BASE64的加解密
* @author Neo
* @date 2018-4-15 22:21:51
*
*/
@SuppressWarnings("restriction")
public class Base64Utils {
public static final String KEY_SHA = "SHA";
public static final String KEY_MD5 = "MD5";

/**
* BASE64解密
*
* @param key
* @return
* @throws Exception
*/
public static byte[] decryptBASE64(String key) throws Exception {
return (new BASE64Decoder()).decodeBuffer(key);
}

/**
* BASE64加密
*
* @param key
* @return
* @throws Exception
*/
public static String encryptBASE64(byte[] key) throws Exception {
return (new BASE64Encoder()).encodeBuffer(key);
}

/**
* MD5加密
*
* @param data
* @return
* @throws Exception
*/
public static byte[] encryptMD5(byte[] data) throws Exception {

MessageDigest md5 = MessageDigest.getInstance(KEY_MD5);
md5.update(data);
return md5.digest();

}

/**
* SHA加密
*
* @param data
* @return
* @throws Exception
*/
public static byte[] encryptSHA(byte[] data) throws Exception {

MessageDigest sha = MessageDigest.getInstance(KEY_SHA);
sha.update(data);

return sha.digest();

}
}

3.然后我们展示RSAUtils：

package com.example.springboottest.common.util;

import javax.crypto.Cipher;
import java.security.*;
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;

/**
* RSA安全编码组件
*
* @version 1.0
* @desc 公钥和私钥存放在properties文件的时候每行的末尾加上“\r\n\” 
* “\r\n” 起到换行的作用,最后的“\”在properties在里表示连接
*
* @author Neo
* @date 2018-4-15 22:23:19
* @since 1.0
*/
public class RSAUtils extends Base64Utils {
public static final String KEY_ALGORITHM = "RSA";
public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

private static final String PUBLIC_KEY = "RSAPublicKey";
private static final String PRIVATE_KEY = "RSAPrivateKey";

/**
* 用私钥对信息生成数字签名
*
* @param data 加密数据
* @param privateKey 私钥
* @return
* @throws Exception
*/
public static String sign(String data, String privateKey) throws Exception {
return sign(data.getBytes(), privateKey);
}

/**
* 用私钥对信息生成数字签名
*
* @param data 加密数据
* @param privateKey 私钥
* @return
* @throws Exception
*/
public static String sign(byte[] data, String privateKey) throws Exception {
// 解密由base64编码的私钥
byte[] keyBytes = decryptBASE64(privateKey);

// 构造PKCS8EncodedKeySpec对象
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);

// KEY_ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

// 取私钥匙对象
PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);

// 用私钥对信息生成数字签名
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(priKey);
signature.update(data);

return encryptBASE64(signature.sign());
}

/**
* 校验数字签名
*
* @param data 加密数据
* @param publicKey 公钥
* @param sign 数字签名
* @return 校验成功返回true 失败返回false
* @throws Exception
*/
public static boolean verify(String data, String publicKey, String sign) throws Exception {
return verify(data.getBytes(), publicKey, sign);
}

/**
* 校验数字签名
*
* @param data 加密数据
* @param publicKey 公钥
* @param sign 数字签名
* @return 校验成功返回true 失败返回false
* @throws Exception
*/
public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {

// 解密由base64编码的公钥
byte[] keyBytes = decryptBASE64(publicKey);

// 构造X509EncodedKeySpec对象
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);

// KEY_ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

// 取公钥匙对象
PublicKey pubKey = keyFactory.generatePublic(keySpec);

Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(pubKey);
signature.update(data);

// 验证签名是否正常
return signature.verify(decryptBASE64(sign));
}

/**
* 解密 
* 用私钥解密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static String decryptByPrivateKey(String data, String key) throws Exception {
return new String(decryptByPrivateKey(Base64Utils.decryptBASE64(data), key));
}

/**
* 解密 
* 用私钥解密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] decryptByPrivateKey(byte[] data, String key) throws Exception {
// 对密钥解密
byte[] keyBytes = decryptBASE64(key);

// 取得私钥
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);

// 对数据解密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, privateKey);

return cipher.doFinal(data);
}

/**
* 解密 
* 用私钥解密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static String decryptByPublicKey(String data, String key) throws Exception {
return new String(decryptByPublicKey(Base64Utils.decryptBASE64(data), key));
}

/**
* 解密 
* 用私钥解密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] decryptByPublicKey(byte[] data, String key) throws Exception {
// 对密钥解密
byte[] keyBytes = decryptBASE64(key);

// 取得公钥
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicKey = keyFactory.generatePublic(x509KeySpec);

// 对数据解密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicKey);
return cipher.doFinal(data);
}

/**
* 加密 
* 用公钥加密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static String encryptByPublicKey(String data, String key) throws Exception {
return Base64Utils.encryptBASE64(encryptByPublicKey(data.getBytes(), key));
}

/**
* 加密 
* 用公钥加密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] encryptByPublicKey(byte[] data, String key) throws Exception {
// 对公钥解密
byte[] keyBytes = decryptBASE64(key);

// 取得公钥
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicKey = keyFactory.generatePublic(x509KeySpec);

// 对数据加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
return cipher.doFinal(data);
}

/**
* 加密 
* 用私钥加密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static String encryptByPrivateKey(String data, String key) throws Exception {
return Base64Utils.encryptBASE64(encryptByPrivateKey(data.getBytes(), key));
}

/**
* 加密 
* 用私钥加密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] encryptByPrivateKey(byte[] data, String key) throws Exception {
// 对密钥解密
byte[] keyBytes = decryptBASE64(key);

// 取得私钥
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);

// 对数据加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
return cipher.doFinal(data);
}

/**
* 取得私钥
*
* @param keyMap
* @return
* @throws Exception
*/
public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
Key key = (Key) keyMap.get(PRIVATE_KEY);

return encryptBASE64(key.getEncoded());
}

/**
* 取得公钥
*
* @param keyMap
* @return
* @throws Exception
*/
public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
Key key = (Key) keyMap.get(PUBLIC_KEY);

return encryptBASE64(key.getEncoded());
}

/**
* 初始化密钥
*
* @return
* @throws Exception
*/
public static Map<String, Object> initKey() throws Exception {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);

KeyPair keyPair = keyPairGen.generateKeyPair();

// 公钥
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

// 私钥
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}

public static void main(String[] args) {
try {
Map<String, Object> map = RSAUtils.initKey();
String publicKey = RSAUtils.getPublicKey(map);
String privateKey = RSAUtils.getPrivateKey(map);
System.out.println("公钥：" + publicKey);
System.out.println("私钥：" + privateKey);
String data = "Java是世界上最好的编程语言";
String encryptData = RSAUtils.encryptByPublicKey(data, publicKey);
System.out.println("加密后：" + encryptData);
String decryptData = RSAUtils.decryptByPrivateKey(encryptData, privateKey);
System.out.println("解密后：" + decryptData);
} catch (Exception e) {
e.printStackTrace();
}
}
}

4.最后展示测试结果：

补充知识：java使用RSA生成公钥和私钥，并进行加解密

废话不多说，上代码：

import javax.crypto.Cipher;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
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
* @throws Exception
*/
public static void genKeyPair() throws Exception {
// 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 = encryptBASE64(publicKey.getEncoded());
// 得到私钥字符串
String privateKeyString = encryptBASE64(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);
}

//编码返回字符串
public static String encryptBASE64(byte[] key) throws Exception {
return (new BASE64Encoder()).encodeBuffer(key);
}

//解码返回byte
public static byte[] decryptBASE64(String key) throws Exception {
return (new BASE64Decoder()).decodeBuffer(key);
}

/**
* 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 = decryptBASE64(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 = encryptBASE64(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 = decryptBASE64(str);
//base64编码的私钥
byte[] decoded = decryptBASE64(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");

String message = "RSA测试aaa";
System.out.println("原文:" + message);

temp = System.currentTimeMillis();
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();

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");
}
}

来源：https://blog.csdn.net/after95/article/details/79954310

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java RSAUtils 加密工具类操作

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