RSA前端加密后端解密

喜欢ヅ旅行 2022-07-13 00:19 532阅读 0赞

1. 准备工作

下载jar包

https://mvnrepository.com/artifact/org.bouncycastle/bcprov-jdk16

加密解密工具类，引用到该包

网上下载三个js文件

2.开始具体工作

前端页面加密，rsaPublicKey是后端写的一个action，返回json对象，json中set了data属性，value为生成的公钥，比如：

f1c2a3f86fdf97e70906e0fa8de9a38c88f893a0a085820d4f50d8f31c545f94243bc373e8611a46203cb5f4d5381b73183912dfec80d04beca0c1e62c2007e3fe6a0f4090371c13beb48a47e1332cf6d1fd031fba4bbf24e1af4b7506aadabbab5d585ecd38ff1594239a1de3c1700b31f4055e7f4b33b1567fcb11132c57dd

var public\_key ;  
$(document).ready(function()\{  
    //填充操作日志  
    $.post("/rsaPublicKey",\{\},function(data)\{  
        if(data.status==200)\{//  
            public\_key = data.data;  
        \}else\{  
            alertErrorMsg("加载公钥失败");  
        \}  
    \});  
\});

通过getEncryptedStr方法，可以把前端value值加密后，获得加密字符串  
function getEncryptedStr(str)\{  
    setMaxDigits(130);  
    var key = new RSAKeyPair("10001","",public\_key);  
    return encryptedString(key, encodeURIComponent(str));  
\}

前端加密完，把加密后的属性提交到后端，后端进行解密，参见下面工具类：

package RSA;  
  
/\*\*  
 \*   
 \*/  
  
  
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;  
  
  
  
   
public class RSAUtil \{  
  
private static String RSAKeyStore = "C:/RSAKey.txt";  
/\*\*  
\* \* 生成密钥对 \*  
\*   
\* @return KeyPair \*  
\* @throws EncryptException  
\*/  
public static KeyPair generateKeyPair() throws Exception \{  
try \{  
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA",  
new org.bouncycastle.jce.provider.BouncyCastleProvider());  
final int KEY\_SIZE = 1024;// 没什么好说的了，这个值关系到块加密的大小，可以更改，但是不要太大，否则效率会低  
keyPairGen.initialize(KEY\_SIZE, new SecureRandom());  
KeyPair keyPair = keyPairGen.generateKeyPair();  
  
System.out.println(keyPair.getPrivate());  
System.out.println(keyPair.getPublic());  
  
saveKeyPair(keyPair);  
return keyPair;  
\} catch (Exception e) \{  
throw new Exception(e.getMessage());  
\}  
\}  
  
  
public static KeyPair getKeyPair() throws Exception \{  
FileInputStream fis = new FileInputStream(RSAKeyStore);  
ObjectInputStream oos = new ObjectInputStream(fis);  
KeyPair kp = (KeyPair) oos.readObject();  
oos.close();  
fis.close();  
return kp;  
\}  
  
  
public static void saveKeyPair(KeyPair kp) throws Exception \{  
  
  
FileOutputStream fos = new FileOutputStream(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);  
int blockSize = cipher.getBlockSize();// 获得加密块大小，如：加密前数据为128个byte，而key\_size=1024  
// 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);  
// 这里面doUpdate方法不可用，查看源代码后发现每次doUpdate后并没有什么实际动作除了把byte\[\]放到  
// ByteArrayOutputStream中，而最后doFinal的时候才将所有的byte\[\]进行加密，可是到了此时加密块大小很可能已经超出了  
// OutputSize所以只好用dofinal方法。  
  
  
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  
\*/  
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());  
\}  
\}  
  
  
/\*\*  
\* \* \*  
\*   
\* @param args \*  
\* @throws Exception  
\*/  
public static void main(String\[\] args) throws Exception \{  
RSAPublicKey rsap = (RSAPublicKey) RSAUtil.generateKeyPair().getPublic();  
String test = "hello world";  
byte\[\] en\_test = encrypt(getKeyPair().getPublic(), test.getBytes());  
byte\[\] de\_test = decrypt(getKeyPair().getPrivate(), en\_test);  
System.out.println(new String(de\_test));  
\}  
\}

可以把生成的公钥和秘钥生成到txt文件，或者保存到数据库里，下面提供对象和blob流转换方法

private byte[] getObject2BlobBytes(Object obj){
        try{
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            ObjectOutputStream outputStream = new ObjectOutputStream(out);
            outputStream.writeObject(obj);
            byte[] bytes = out.toByteArray();
            outputStream.close();
            return bytes;
        }catch(Exception e){
            logger.error(e.getMessage());
        }
        return null;
    }
    private Object bytes2Object(byte[] bytes) throws IOException {
        ByteArrayInputStream inputStream = null;
        ObjectInputStream in = null;
        try{
            inputStream = new ByteArrayInputStream(bytes);
            in = new ObjectInputStream(inputStream);
            Object obj = in.readObject();
            return obj;
        }catch (Exception e){
            logger.error(e.getMessage());
        }finally {
            if(inputStream != null){
                inputStream.close();
            }
            if(in != null){
                in.close();
            }
        }
        return null;
    }

如果在解密过程中，碰到

# [RSA Bad Arguments][]问题： #

# 可参见下面解决办法： #

# public final class HexUtil \{        /\*\*        \* 16进制 To byte\[\]<br>        \* <font color='red'> fix byte\[\] en\_pwd = new BigInteger(pwd, 16).toByteArray();bug</font>        \*         \* @param hexString        \* @return byte\[\]        \*/       public static byte\[\] hexStringToBytes(String hexString) \{            if (hexString == null || hexString.equals("")) \{                return null;           \}           hexString = hexString.toUpperCase();           int length = hexString.length() / 2;           char\[\] hexChars = hexString.toCharArray();           byte\[\] d = new byte\[length\];           for (int i = 0; i < length; i++) \{                int pos = i \* 2;               d\[i\] = (byte) (charToByte(hexChars\[pos\]) << 4 | charToByte(hexChars\[pos + 1\]));           \}           return d;       \}             /\*\*        \* Convert char to byte        \*         \* @param c char        \* @return byte        \*/       private static byte charToByte(char c) \{            return (byte) "0123456789ABCDEF".indexOf(c);       \}   \}    #

[RSA Bad Arguments]: http://blog.csdn.net/spy19881201/article/details/9095149