RSA非对称加密（java版）
对于什么是RSA百度上写的很清楚，我就不重复了，直接看代码说问题。
web端
RSA在web端采用公钥加密需要依赖[jsencrypt.js](http://passport.cnblogs.com/scripts/jsencrypt.min.js)
引用的时候很简单：
var encrypt = new JSEncrypt();
encrypt.setPublicKey("后台传过来的公钥");
encrypt.encrypt("需要加密的数据")
java后台RSA加密的工具类：
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Security;
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.commons.codec.binary.Base64;
public class RSAUtils {
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";
public static byte[] decryptBASE64(String key) {
return Base64.decodeBase64(key);
}
public static String encryptBASE64(byte[] bytes) {
return Base64.encodeBase64String(bytes);
}
/**
* 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));
}
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>
* 用私钥解密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] decryptByPrivateKey(String data, String key)
throws Exception {
return decryptByPrivateKey(decryptBASE64(data),key);
}
/**
* 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(String 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.getBytes());
}
/**
* 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);
}
/**
* 取得私钥
*
* @param keyMap
* @return
* @throws Exception
*/
public static String getPrivateKey(Map<String, Key> 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, Key> keyMap)
throws Exception {
Key key = keyMap.get(PUBLIC_KEY);
return encryptBASE64(key.getEncoded());
}
/**
* 初始化密钥
*客户端通过公钥进行加密，服务端通过私钥进行解密
* JS端应用需要依赖jsencrypt.js 下载地址http://www.oschina.net/action/code/download?code=48994&id=71045
* @return
* @throws Exception
*/
public static Map<String, Key> initKey() throws Exception {
KeyPairGenerator keyPairGen = KeyPairGenerator
.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
Map<String, Key> keyMap = new HashMap(2);
keyMap.put(PUBLIC_KEY, keyPair.getPublic());// 公钥
keyMap.put(PRIVATE_KEY, keyPair.getPrivate());// 私钥
return keyMap;
}
}
生成公，私钥
Map<String, Key> keyMap = RSAUtils.initKey();
publicKey = RSAUtils.getPublicKey(keyMap);
privateKey = RSAUtils.getPrivateKey(keyMap);
私钥解密
String temp= new String(RSAUtils.decryptByPrivateKey("加密过的数据","后台生成的私钥"),"utf-8")
大体就这么多，再说问题：
- byte[] 转String的时候注意编码格式
- 在web端传到java后台的时候注意字符替换（RSA加密的数据中加号会被替换成空格，然后就解密不出来了）
- 这次是为以前的客户升级，已经没有源码了，以后可以tomcat远程调试（参考链接）
- 如果服务器操作系统是win，可以把控制台打印的东西写入文件查看（ System.setErr(new PrintStream(new FileOutputStream("output.txt"))) 默认在tomcat的bin目录中）
- 以后想在jar中加class，但是没办法打包时，可以按照文件目录建文件，把class文件直接放入文件目录中就可以，jvm读的时候会先读它
