java js 非对称加密算法 java非对称加密算法rsa

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mob6454cc72f29c 2023-08-19 08:46:19

文章标签 java js 非对称加密算法 java ci System 文章分类 Java 后端开发

非对称加密算法需要两个密钥：公开密钥（publickey）和私有密钥（privatekey）。公开密钥与私有密钥是一对，如果用公开密钥对数据进行加密，只有用对应的私有密钥才能解密；如果用私有密钥对数据进行加密，那么只有用对应的公开密钥才能解密。因为加密和解密使用的是两个不同的密钥，所以这种算法叫作非对称加密算法

package org.icesnow.jeasywx.util.security;



import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
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;


import javax.crypto.Cipher;


import org.apache.log4j.Logger;


import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;


/**
 * @author: 782987839@qq.com
 * @date：2016-3-23下午12:25:07
 * @version: 1.0
 * @describe: JAVA实现RSA加密,非对称加密算法
 * 
 */
public class RSA {
  private static Logger logger = Logger.getLogger(RSA.class);

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";


/**
* 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();
//  logger.info("------" + publicKey);
// 私钥
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
//  logger.info("------" + publicKey);

Map<String, Object> keyMap = new HashMap<String, Object>(2);


keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}


/**
* 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());
}


/**
* 解密<br>
* 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<br>
* 用公钥解密
* 
* @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<br>
* 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<br>
* 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);
}

/**
* 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(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));
}


private static byte[] decryptBASE64(String key) throws Exception {
return (new BASE64Decoder()).decodeBuffer(key);
}


private static String encryptBASE64(byte[] key) throws Exception {
return (new BASE64Encoder()).encodeBuffer(key);
}

public static void main(String[] args) {
Map<String, Object> keyMap;
try {
//取得公钥和么私钥
keyMap = initKey();
String publicKey = getPublicKey(keyMap);
logger.info("字符类型公钥:" + publicKey);


String privateKey = getPrivateKey(keyMap);
logger.info("字符类型私钥:" + privateKey);



System.err.println("公钥加密——私钥解密");
       String source = "这是一行没有任何意义的文字，你看完了等于没看，不是吗？";
       System.out.println("\r加密前文字：\r\n" + source);
       byte[] data = source.getBytes();
       byte[] encodedData = encryptByPublicKey(data, publicKey);
       System.out.println("加密后文字：\r\n" + encryptBASE64(encodedData));
       byte[] decodedData = decryptByPrivateKey(encodedData, privateKey);
       String target = new String(decodedData);
       System.out.println("解密后文字: \r\n" + target);
       
       System.err.println("私钥加密——公钥解密");
       String source1 = "这是一行测试RSA数字签名的无意义文字";
       System.out.println("原文字：\r\n" + source1);
       byte[] data1 = source1.getBytes();
       byte[] encodedData1 = encryptByPrivateKey(data1, privateKey);
       System.out.println("加密后：\r\n" + new String(encodedData1));
       byte[] decodedData1 = decryptByPublicKey(encodedData1, publicKey);
       String target1 = new String(decodedData1);
       System.out.println("解密后: \r\n" + target1);
       System.err.println("私钥签名——公钥验证签名");
       String sign = sign(encodedData, privateKey);
       System.err.println("签名:\r" + sign);
       boolean status = verify(encodedData, publicKey, sign);
       System.err.println("验证结果:\r" + status);
//  //对内容进行加密和解密
String str = "this is test RSA";
byte[] strByte = str.getBytes();
//  //私钥加密 
byte[] encode = encryptByPrivateKey(strByte,privateKey);
logger.info("私钥加密结果:" + encryptBASE64(encode));
//公钥解密
byte[] decode = decryptByPublicKey(encode,publicKey);
logger.info("公钥解密结果:" + new String(decode));

} catch (Exception e) {
e.printStackTrace();
}
}


}

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