Decrypting String using HexToBinary

[User (Old forums)]

#42988 |

Hello,

I am currently working on converting a method we have written using Classic ASP into a C# .Net DLL and I’ve come across a stumbling block. 

What we have is an encrypted string stored in a registry setting that we retrieve and decrypt using a HexToBinary function.  I have managed to duplicate the Hex string that is created by the ASP code via C# using a modified HexToBinary function and receive a variant byte array back when I call FromString method of the XceedEncryption class:

<code>

public static object HexToBinary(string strHexValue, XceedEncryption xDecrypter)

{

int i = 0;

long lngVal;

string tmpHexValue = “”;

string strBinaryValue = “”;

object varBinaryValue = new object();

StringBuilder sb = new StringBuilder();

try

{

while (i < strHexValue.Length)

{

tmpHexValue = strHexValue.Substring(i, 2);

lngVal =

long.Parse(tmpHexValue, NumberStyles.AllowHexSpecifier);

sb.Append(

Convert.ToChar(lngVal).ToString());

i += 2;

}

strBinaryValue = sb.ToString();

varBinaryValue = xDecrypter.FromString(strBinaryValue);

}

catch (Exception ex)

{

MessageBox.Show(ex.Message);

}

return varBinaryValue;

}

</code>

From the ASP code I saw that the result of the call to the Decrypt method is simply cast to a string and there you get your resulting decrypted string.  This won’t work in C#, at least I can’t get it to so I just have the byte array:

<code> 

varDataToDecrypt = HexToBinary(strEncrypt, xDecrypter);

varDataDecypted = (

byte[])xDecrypter.Decrypt(ref varDataToDecrypt, true);

</code>

I am getting a variant byte array back from the Decrypt method in C# so it looks like it good until I need to return the actual decrypted string.  I’m just not sure how to get the resulting string from the byte array.  I’m not all that great with C# yet (if you can’t tell) so I apologize for any sloppy code.

Thanks in advance,

Tony

Imported from legacy forums. Posted by Tony (had 3995 views)

[Xceed Support]

#42989

Hi Tony,

 

To get the resulting string, data, from your byte array, varDataDecypted, you will need to use a Text Encoding as follow:

 

string data = System.Text.Encoding.Unicode.GetString( ( byte[] )varDataDecypted );

 

 

Regards,

 

Imported from legacy forums. Posted by Mohamed [Xceed] (had 514 views)

[User (Old forums)]

#42990

Thanks for the reply Mohamed.

It returned part of the string I was looking for but most of it was just garbled, like special character boxes.  I must have not set things up right.

Imported from legacy forums. Posted by Tony (had 5744 views)

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