Migrating from JSP/Servlets to ASP.NET

Re: How to solve System.Security.Cryptography.CryptographicException: Bad Data error

TATWORTH — Sun, 01 Mar 2009 11:32:58 GMT

For some tolerably robust encrypt/decrypt routines, please see the encypt/decrypt rotines within the CommonData library at http://www.CodePlex.Com/CommonData. (In their current form, they are not protected against storage/transmission errors)

How to solve System.Security.Cryptography.CryptographicException: Bad Data error

thanigaimaniveena — Thu, 26 Feb 2009 11:36:12 GMT

Dear Experts Thanx for reply.I gor idea from that links.One more doubt when i decrypt the ecncrypt string using auto generate key its showing error as System.Security.Cryptography.CryptographicException: Bad Data.

I give the my function

private void DecryptFunction()

{

try

{

//string strEncrypt = "b0154bc4a0f77d3056ff0009563ec9ab";

string strEncrypt = "2f8ae3760636f348e0cb711c5109b78f";

TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();

//tdes.Key = Encoding.UTF8.GetBytes("ErXXz+VpJpQ7K/bmpzAkDg==");

tdes.Key = Encoding.UTF8.GetBytes("22tqlER6RPmVvA2omvJJxg==");

tdes.Mode = CipherMode.ECB;

tdes.Padding = PaddingMode.PKCS7;

ICryptoTransform crypt = tdes.CreateDecryptor();

byte[] cipher = FromHex(strEncrypt);

byte[] plain = crypt.TransformFinalBlock(cipher, 0, cipher.Length); ( Here Error Showing )

Response.Write("Decryped string : " + System.Text.Encoding.UTF8.GetString(plain) + "<br/>");

}

catch (Exception ex)

{

Response.Write(ex.Message);

}

I would appreciate some help

Thanx

Regards

mani

Re: How to generate auto secret key in asp.net

qwe123kids — Wed, 25 Feb 2009 15:08:05 GMT

Hi,

Kindly Go Through The Follwing Links

http://coding.derkeiler.com/Archive/Java/comp.lang.java.programmer/2008-11/msg01656.html

http://snippets.dzone.com/tag/csharp

http://snippets.dzone.com/posts/show/5535

Hope It Help You

Re: How to generate auto secret key in asp.net

thanigaimaniveena — Wed, 25 Feb 2009 12:28:44 GMT

Thanx for reply.I got it.

Now i want encrypt the input string using ciper class.I have some codes which is converted from java.I want use this function in .net
i give the function as follows as

'Method for encrypt the input value using the secret key

Private Function Encrypt(ByVal msg As String, ByVal skeySpec As SecretKeySpec) As String

Dim hexString As String = ""

Try

Dim cipher As Cipher = cipher.getInstance("AES")

cipher.init(cipher.ENCRYPT_MODE, skeySpec)

Dim encrypted() As SByte = cipher.doFinal(msg.getBytes())

hexString = asHex(encrypted)

Catch ex As Exception

Response.Write(ex.Message)

End Try

Return hexString

End Function

Here
msg as input string for example msg="Sample Input Text"
and secretkeyspec as autogeneratekey for example skeySpec="GbxDwxcjvjtpi0+lQuyfHg=="
i need encrypt string as "fc8caff8581f9a3920b788490c3569ffb345e54c7f72a73ddb76256ff81fbfd6"
problem is ciper class doesnt support in .net

Help me

Thanx

Regards
Mani

Re: How to generate auto secret key in asp.net

qwe123kids — Wed, 25 Feb 2009 10:14:32 GMT

Hi,

import java.security.Key;
import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;

public class MainClass {

public static void main(String[] args) throws Exception {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

KeyGenerator generator = KeyGenerator.getInstance("AES", "BC");
generator.init(128);

Key keyToBeWrapped = generator.generateKey();

System.out.println("input : " + new String(keyToBeWrapped.getEncoded()));
Cipher cipher = Cipher.getInstance("AESWrap", "BC");

KeyGenerator KeyGen = KeyGenerator.getInstance("AES", "BC");
KeyGen.init(256);

    Key wrapKey = KeyGen.generateKey();
    cipher.init(Cipher.WRAP_MODE, wrapKey);
    byte[] wrappedKey = cipher.wrap(keyToBeWrapped);

System.out.println("wrapped : " + new String(wrappedKey));

    cipher.init(Cipher.UNWRAP_MODE, wrapKey);
    Key key = cipher.unwrap(wrappedKey, "AES", Cipher.SECRET_KEY);
    System.out.println("unwrapped: " + new String(key.getEncoded()));
}
}

Before That U have Import Java Libary

Below link may help you

http://forums.asp.net/t/90461.aspx

For importing java Libary.

Hope Below Code Help U

Thanks,

How to generate auto secret key in asp.net

thanigaimaniveena — Wed, 25 Feb 2009 09:38:17 GMT

Dear Experts,

I had one function in converted from java for generate the auto secret key purpose for encrypt and decrypt the using using AES algorithm..when i used this function in .net its showing SecretKeySpec and KeyGenerator is not defined.Even i used System.Security.Cryptography header name space also.

I give the my codes.If any body know help me

Private Function keygeneration() As SecretKeySpec

Dim skeySpec As SecretKeySpec = Nothing

Try

Dim kgen As KeyGenerator = KeyGenerator.getInstance("AES")

kgen.init(128)

Dim skey As SecretKey = kgen.generateKey()

Dim key() As SByte = skey.getEncoded()

skeySpec = New SecretKeySpec(key, "AES")Catch e As Exception

Response.Write(e.Message)

End Try

Return skeySpec

End Function

Reply me

Thanx & Regards

Thanigaimani