RSA前端JS加密，后端JAVA解密实现

用RSA非对称加密方式实现。后台生成rsa密钥对，然后在页面设置rsa公钥，提交时用公钥加密密码，生成的密文传到后台，后台再用私钥解密，获取密码明文。
   这样客户端只需要知道rsa加密方式和公钥，前台不知道私钥是无法解密的，此解决方案还是相对比较安全的。
   需要到http://www.bouncycastle.org下载bcprov-jdk16-140.jar文件。
缺陷：由于进行的都是大数计算，使得RSA最快的情况也比DES慢上100倍，无论是软件还是硬件实现。所以一般来说只用于少             量数据加密。
下面我们就来一个实际的例子：

1、前端加密需要引入Barrett.js、BigInt.js和RSA.js。

<script src="/rsa/RSA.js" type="text/javascript"></script>
<script src="/rsa/BigInt.js" type="text/javascript"></script>
<script src="/rsa/Barrett.js" type="text/javascript"></script>

复制代码 2、前端加密代码：

encryptedString : (function(paramStr, rsaKey){
setMaxDigits(130);
//第一个参数为加密指数、第二个参数为解密参数、第三个参数为加密系数
key = new RSAKeyPair("10001", "", rsaKey);
//返回加密后的字符串
return encryptedString(key, encodeURIComponent(paramStr));
})

复制代码其中的加密系数可以自定义，这里为：8246a46f44fc4d961e139fd70f4787d272d374532f4d2d9b7cbaad6a15a8c1301319aa6b3f30413b859351c71938aec516fa7147b69168b195e81df46b6bed7950cf3a1c719d42175f73d7c97a85d7d20a9e83688b92f05b3059bb2ff75cd7190a042cd2db97ebc2ab4da366f2a7085556ed613b5a39c9fdd2bb2595d1dc23b5
3、后台RSA加密解密方法如下：

import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
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.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import javax.crypto.Cipher;
import org.apache.commons.lang.StringUtils;
import com.jd.uwp.common.Constants;
/**
* RSA 工具类。提供加密，解密，生成密钥对等方法。
* 需要bcprov-jdk16-140.jar包。
*
*/
public class RSAUtil {
private static String RSAKeyStore = "RSAKey.txt";
/**
* * 生成密钥对 *
* @return KeyPair *
* @throws EncryptException
*/
public static KeyPair generateKeyPair(String basePath) throws Exception {
try {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA",
new org.bouncycastle.jce.provider.BouncyCastleProvider());
//大小
final int KEY_SIZE = 1024;
keyPairGen.initialize(KEY_SIZE, new SecureRandom());
KeyPair keyPair = keyPairGen.generateKeyPair();
saveKeyPair(keyPair, basePath);
return keyPair;
} catch (Exception e) {
throw new Exception(e.getMessage());
}
}
/**
* 获取密钥对
* @return
* @throws Exception
*/
public static KeyPair getKeyPair(String basePath) throws Exception {
FileInputStream fis = new FileInputStream(StringUtils.isNotBlank(basePath) ? (basePath + RSAKeyStore) : RSAKeyStore);
ObjectInputStream oos = new ObjectInputStream(fis);
KeyPair kp = (KeyPair) oos.readObject();
oos.close();
fis.close();
return kp;
}
/**
* 保存密钥
* @param kp
* @throws Exception
*/
public static void saveKeyPair(KeyPair kp, String basePath) throws Exception {
FileOutputStream fos = new FileOutputStream(StringUtils.isNotBlank(basePath) ? (basePath + RSAKeyStore) : RSAKeyStore);
ObjectOutputStream oos = new ObjectOutputStream(fos);
// 生成密钥
oos.writeObject(kp);
oos.close();
fos.close();
}
/**
* * 生成公钥 *
* @param modulus *
* @param publicExponent *
* @return RSAPublicKey *
* @throws Exception
*/
public static RSAPublicKey generateRSAPublicKey(byte[] modulus,
byte[] publicExponent) throws Exception {
KeyFactory keyFac = null;
try {
keyFac = KeyFactory.getInstance("RSA",
new org.bouncycastle.jce.provider.BouncyCastleProvider());
} catch (NoSuchAlgorithmException ex) {
throw new Exception(ex.getMessage());
}
RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(
modulus), new BigInteger(publicExponent));
try {
return (RSAPublicKey) keyFac.generatePublic(pubKeySpec);
} catch (InvalidKeySpecException ex) {
throw new Exception(ex.getMessage());
}
}
/**
* * 生成私钥 *
* @param modulus *
* @param privateExponent *
* @return RSAPrivateKey *
* @throws Exception
*/
public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus,
byte[] privateExponent) throws Exception {
KeyFactory keyFac = null;
try {
keyFac = KeyFactory.getInstance("RSA",
new org.bouncycastle.jce.provider.BouncyCastleProvider());
} catch (NoSuchAlgorithmException ex) {
throw new Exception(ex.getMessage());
}
RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger(
modulus), new BigInteger(privateExponent));
try {
return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec);
} catch (InvalidKeySpecException ex) {
throw new Exception(ex.getMessage());
}
}
/**
* * 加密 *
* @param key
* 加密的密钥 *
* @param data
* 待加密的明文数据 *
* @return 加密后的数据 *
* @throws Exception
*/
public static byte[] encrypt(PublicKey pk, byte[] data) throws Exception {
try {
Cipher cipher = Cipher.getInstance("RSA",
new org.bouncycastle.jce.provider.BouncyCastleProvider());
cipher.init(Cipher.ENCRYPT_MODE, pk);
// 获得加密块大小，如：加密前数据为128个byte，而key_size=1024
int blockSize = cipher.getBlockSize();
// 加密块大小为127
// byte,加密后为128个byte;因此共有2个加密块，第一个127
// byte第二个为1个byte
int outputSize = cipher.getOutputSize(data.length);// 获得加密块加密后块大小
int leavedSize = data.length % blockSize;
int blocksSize = leavedSize != 0 ? data.length / blockSize + 1 : data.length / blockSize;
byte[] raw = new byte[outputSize * blocksSize];
int i = 0;
while (data.length - i * blockSize > 0) {
if (data.length - i * blockSize > blockSize) {
cipher.doFinal(data, i * blockSize, blockSize, raw, i * outputSize);
} else {
cipher.doFinal(data, i * blockSize, data.length - i * blockSize, raw, i * outputSize);
}
i++;
}
return raw;
} catch (Exception e) {
throw new Exception(e.getMessage());
}
}
/**
* * 解密 *
*
* @param key
* 解密的密钥 *
* @param raw
* 已经加密的数据 *
* @return 解密后的明文 *
* @throws Exception
*/
@SuppressWarnings("static-access")
public static byte[] decrypt(PrivateKey pk, byte[] raw) throws Exception {
try {
Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
cipher.init(cipher.DECRYPT_MODE, pk);
int blockSize = cipher.getBlockSize();
ByteArrayOutputStream bout = new ByteArrayOutputStream(64);
int j = 0;
while (raw.length - j * blockSize > 0) {
bout.write(cipher.doFinal(raw, j * blockSize, blockSize));
j++;
}
return bout.toByteArray();
} catch (Exception e) {
throw new Exception(e.getMessage());
}
}
/**
* 解密方法
* paramStr ->密文
* basePath ->RSAKey.txt所在的文件夹路径
**/
public static String decryptStr(String paramStr, String basePath) throws Exception{
byte[] en_result = new BigInteger(paramStr, 16).toByteArray();
byte[] de_result = decrypt(getKeyPair(basePath).getPrivate(), en_result);
StringBuffer sb = new StringBuffer();
sb.append(new String(de_result));
//返回解密的字符串
return sb.reverse().toString();
}
}

复制代码 4、前端提交到后端解密调用:

//前端表单提交
$.ajax({
url : contextPath + "test.action",
//加密传输
data : {pwd:encryptedString ($("#pwd").val(), "adasdasdasdasdadsasdasdasdasd")},
type : "post",
datatype : "json",
success : function(retData){
}
});
//后端解密代码
RSAUtil.decryptStr(paramMap.getString("pwd"), request.getSession().getServletContext().getRealPath("/"));

复制代码

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RSA前端JS加密，后端JAVA解密实现

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