Rijndael usage

David Gray david.gray at turpin-distribution.com
Wed May 10 10:09:03 CEST 2006


Hi David, 
Thanks for the info, even if it's not what I wanted to hear.  :-)  

What do you mean by "raw Rijndael"?   

The C# code that the software house are using is shown below,  even if 
I clone this program am I likely to be able to decrypt without them sending 
me a key in ASCII format? 

Thanks 
David. 


public string DecodeString(byte[] encodedsource)
        {
            System.Text.UTF8Encoding encoding = new
System.Text.UTF8Encoding();
            byte[] bytes = encodedsource;
            
            MemoryStream memstream = new MemoryStream();
            memstream.Write(bytes, 0, bytes.Length);
            memstream.Position = 0;

            SymmetricAlgorithm algorithm =
SymmetricAlgorithm.Create("RijnDael");
            algorithm.Key = key;
            algorithm.IV = iv;
            ICryptoTransform transform = algorithm.CreateDecryptor();

            CryptoStream cryptstream = new CryptoStream(memstream,
transform, CryptoStreamMode.Read);
            
            StreamReader reader = new StreamReader(cryptstream);
            string returnstring = reader.ReadToEnd();
            memstream.Dispose();
            reader.Dispose();
            cryptstream.Dispose();

            return returnstring;
        }


-----Original Message-----
From: David Shaw [mailto:dshaw at jabberwocky.com] 
Sent: 09 May 2006 22:16
To: gnupg-users at gnupg.org
Subject: Re: Rijndael usage


On Tue, May 09, 2006 at 03:55:15PM +0100, David Gray wrote:
> Hello all,
> 
> Wonder if anyone could give advice on using GnuPG to decrypt
> Files encoded with the Rijndael cipher.  
> 
> One of our customers is using a software house to build a website that
> will send encrypted order files to us (the distributor of their stock).
The
> files 
> Are basically CSV format data files.   
> 
> I've received an email from them containing two symmetric keys for 
> testing
> purposes.  These do not look like any I've seen before...  
> 
> key: "ABCDE%^$ABCDE-99" and
> iv: "ABCDE$*@ABCDE-99"
> 
> (Values changed for email)

You can't use GPG or PGP to decrypt this.  It looks like they're encrypting
using raw Rijndael.

David

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