RSA加密和解密。将加密转换为解密时出错 [英] RSA Encryption And Decryption . Getting Error When I Convert Encryption To Decryption

问题描述

我使用RSA算法进行加密和解密。我转换为字符串值加密它正常工作。当我将加密转换为解密时，我得到错误。下面我通过我的代码。请给我任何帮助

  public   final  字符串 modulusString =   2rRVVVFJRbH / wAPDtnwZwu + nxU + AZ6uXxh / SW + AMCBogg7vndZsnRiHoLttYYPqOyOhfgaBOQogrIfrKL4lipK4m52SBzw / FfcM9DsKs / rYR83tBLiIAfgdnVjF27tZID + HJMFTiI30mALjr7 + TFP + 2lIACXA1RIKTk7S9pDmX8 =; 
  public   final   String  publicExponentString =   AQAB; 
 
 加密代码： 
 
  public   String  EncryptionValue（ String  EncryptionValue） throws  Base64DecodingException，NoSuchAlgorithmException，InvalidKeySpecException，NoSuchPaddingException，InvalidKeyException， IllegalBlockSizeException，UnsupportedEncodingException，BadPaddingException 
 {
 
  byte  [] modulebytes = Base64.decode（modulusString）; 
  byte  [] exponentbytes = Base64.decode（publicExponentString）; 
 
 BigInteger module =  new  BigInteger（ 1 ，modulebytes）; 
 BigInteger publicexponent =  new  BigInteger（ 1 ，exponentbytes）; 
 
 RSAPublicKeySpec rsaPubKey =  new  RSAPublicKeySpec（module，publicexponent）; 
 KeyFactory fact = KeyFactory.getInstance（  RSA）; 
 PublicKey pubKey = fact.generatePublic（rsaPubKey）; 
 
 Cipher cipher = Cipher.getInstance（  RSA / ECB / PKCS1Padding ）; 
 cipher.init（Cipher.ENCRYPT_MODE，pubKey）; 
 
  byte  [] plainBytes = EncryptionValue.getBytes（  UTF-8\" ）; 
  byte  [] cipherData = cipher.doFinal（plainBytes）; 
  String  encryptedString = Base64.encode（cipherData）; 
 
  return  encryptedString; 
} 
 
 
 解密代码： 
 
 
  public  字符串 DecryptionValue（ String  DecryptionValue） throws  Base64DecodingException，NoSuchAlgorithmException，InvalidKeySpecException，NoSuchPaddingException，InvalidKeyException，UnsupportedEncodingException，IllegalBlockSizeException，BadPaddingException 
 {
  byte  [] modulebytes = Base64.decode（ modulusString）; 
  byte  [] exponentbytes = Base64.decode（publicExponentString）; 
 
 BigInteger modulus =  new  BigInteger（ 1 ，modulebytes）; 
 BigInteger exponent =  new  BigInteger（ 1 ，exponentbytes）; 
 
 RSAPrivateKeySpec rsaPrivKey =  new  RSAPrivateKeySpec（modulus，exponent）; 
 KeyFactory fact = KeyFactory.getInstance（  RSA）; 
 PrivateKey privKey = fact.generatePrivate（rsaPrivKey）; 
 
 Cipher cipher = Cipher.getInstance（  RSA / ECB / PKCS1Padding ）; 
 cipher.init（Cipher.DECRYPT_MODE，privKey）; 
 
  byte  [] base64String = Base64.decode（DecryptionValue）; 
  byte  [] plainBytes =  new   String (base64String).getBytes(  UTF-8）; 
 plainBytes = cipher.update（plainBytes）; 
  byte  [] values = cipher.doFinal（plainBytes）; 
 
  return   new   String （values，  UTF-8）; 
} 

我的错误：

线程中的异常  main javax.crypto。 BadPaddingException：解密错误
 at sun.security.rsa.RSAPadding.unpadV15（RSAPadding.java： 380 ）
 at sun.security.rsa。 RSAPadding.unpad（RSAPadding.java： 291 ）
 at com.sun.crypto.provider.RSACipher.doFinal（RSACipher.java： 363 ）
 at com.sun.crypto.provider.RSACipher.engineDoFinal（RSACipher.java： 389 ）
 at javax.crypto.Cipher.doFinal（Cipher.java： 2121 ）
 at cryptocodefinal.CryptoCodeFinal.DecryptionValue（CryptoCodeFinal.java： 79 ）
 at cryptocodefinal.CryptoCodeFinal.main（CryptoCodeFinal.java： 148 ）

解决方案

我想你会发现被解密的字符串的长度是错误的。



你需要填充数据作为必需的块大小，256字节IIRC，否则你会得到一个糟糕的填充错误。加密数据是 buyte [] ，然后将其转换为 String 。尝试不进行转换，你应该能够使事情有效。

hi,

i used RSA Algorithm to encryption and decryption . i convert to string value to encryption it's working properly. when i convert encryption to decryption that time i get error . below i past my code. please any one help to me

 public final String modulusString = "2rRVVVFJRbH/wAPDtnwZwu+nxU+AZ6uXxh/sW+AMCBogg7vndZsnRiHoLttYYPqOyOhfgaBOQogrIfrKL4lipK4m52SBzw/FfcM9DsKs/rYR83tBLiIAfgdnVjF27tZID+HJMFTiI30mALjr7+tfp+2lIACXA1RIKTk7S9pDmX8=";
   public final String publicExponentString = "AQAB";
  
Encryption Code :

 public String EncryptionValue(String EncryptionValue) throws Base64DecodingException, NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, UnsupportedEncodingException, BadPaddingException
    {

        byte[] modulebytes = Base64.decode(modulusString);
        byte[] exponentbytes = Base64.decode(publicExponentString);
       
        BigInteger module = new BigInteger(1,modulebytes);
        BigInteger publicexponent = new BigInteger(1,exponentbytes);
        
            RSAPublicKeySpec rsaPubKey = new RSAPublicKeySpec(module, publicexponent);
        KeyFactory fact = KeyFactory.getInstance("RSA");
        PublicKey pubKey = fact.generatePublic(rsaPubKey);

        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);

        byte[] plainBytes = EncryptionValue.getBytes("UTF-8");
        byte[] cipherData = cipher.doFinal( plainBytes );
        String encryptedString = Base64.encode(cipherData);
        
        return encryptedString;
    }


Decryption Code :


  public String DecryptionValue(String DecryptionValue) throws Base64DecodingException, NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, InvalidKeyException, UnsupportedEncodingException, IllegalBlockSizeException, BadPaddingException
    {
        byte[] modulebytes = Base64.decode(modulusString);
        byte[] exponentbytes = Base64.decode(publicExponentString);
        
        BigInteger modulus = new BigInteger(1, modulebytes );
        BigInteger exponent = new BigInteger(1, exponentbytes);

        RSAPrivateKeySpec rsaPrivKey = new RSAPrivateKeySpec(modulus, exponent);
        KeyFactory fact = KeyFactory.getInstance("RSA");
        PrivateKey privKey = fact.generatePrivate(rsaPrivKey);

        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        cipher.init(Cipher.DECRYPT_MODE, privKey);

        byte[] base64String = Base64.decode(DecryptionValue);
        byte[] plainBytes = new String(base64String).getBytes("UTF-8");
        plainBytes = cipher.update(plainBytes);
        byte[] values = cipher.doFinal(plainBytes);

        return new String(values, "UTF-8");
    }

My Error :

Exception in thread "main" javax.crypto.BadPaddingException: Decryption error
	at sun.security.rsa.RSAPadding.unpadV15(RSAPadding.java:380)
	at sun.security.rsa.RSAPadding.unpad(RSAPadding.java:291)
	at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:363)
	at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:389)
	at javax.crypto.Cipher.doFinal(Cipher.java:2121)
	at cryptocodefinal.CryptoCodeFinal.DecryptionValue(CryptoCodeFinal.java:79)
	at cryptocodefinal.CryptoCodeFinal.main(CryptoCodeFinal.java:148)

解决方案

I think you'll find that the length of the string being decrypted is wrong.

You need to pad out the data to be the required block size, 256 bytes IIRC, or else you get a bad padding error. The encrypted data is buyte[] and you convert it to String. Try not doing the conversion and you should be able to make things work.

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