SharpDevelop Community

 Hello,

 I created a file in winzip which contains a text file and a folder with a text file. I password protected the file with 256 bit aes encryption. When I run the following code:

Try
   Dim z As New FastZip()
   z.Password = "qqqqqq"
   z.ExtractZip("c:\bam.zip", "C:\bam", "")
   MsgBox("done")
 Catch
   MsgBox("crash!")

End Try

The "done" msgbox appears immediatly and but the files are not extracted. Everything unzips fine without the password set on the zip file. 

 Thanks for any help.

(after clicking the related tab it appears 256 is not supported. Is this correct?  Any plans for this addition in the future?)

 See the roadmap... it is vague, but does hint at it:

http://wiki.sharpdevelop.net/SharpZipLib_Roadmap.ashx 

Yes, AES is currently not supported, it requires a new decryption algorithm. It's certainly possible but the problem at its core is that particular cipher mode that Winzip are using is not supported intrinsically in .Net 2.0  I went thru of the Winzip pages and as I said in this post

http://community.sharpdevelop.net/forums/p/155/19830.aspx#19830

 " had a go at decrypting an AES-encrypted WinZip file.  Getting hold of the encrypted content stream was straightforward as the doco on the winzip site was correct, and the existing SharpZip code easy to modify.  I then tried using the RijndaelManaged class in .NET 2.0.  The problem is that WinZip are using AES in CTR mode (counter mode) but this is not a supported cipher mode in the RijndaelManaged library. "

There are a number of ways you can "run" AES. CTR mode is quite a good choice for a winzip file. I don't know why MS didn't include this mode. The source for the .NET libraries is available so maybe someone with a head for XOR'ing 16 byte blocks could have a crack at it.