Comments for Real Coders Coding

Comment on System.Threading.Timer Stops Firing in Windows Server 2003 SP1 by Olin Hamilton

Olin Hamilton — Thu, 06 Aug 2009 19:06:45 +0000

I too am experiencing this .NET 2.0 SP2 on Win2k3 SP2 x32. Does anyone know of a fix?

Comment on .Net Encryption simple AES wrapper by Blue Beetle

Blue Beetle — Wed, 20 May 2009 20:59:39 +0000

I’ve enforced some wrapping on the code blocks so, hopefully, thing’s won’t get clipped in the browser.

You may still end up with artifacts (like extra line breaks, html constants, etc.) if you cut-and-paste. There are just so many apps to paste from and so many to paste into that there is no cureall. Still, hopefully the highlighting, etc. will help and, remember, if you see ampersands (&), SGML tags, etc. in your paste, they’re html translations of C# (almost never valid C# themselves).

Comment on .Net Encryption simple AES wrapper by Blue Beetle

Blue Beetle — Wed, 20 May 2009 19:43:57 +0000

There was definitely a problem in GetKey, p.LegalKeySizes[0].MinSize returns a number of bits, and what’s needed is a number of bytes, so, I’ve fixed this in the for loop boundaries and count conditions (it should also be a bit more readable). Thanks for seeing that bug, Michael.

the lt; and gt; things are html constants not C#, they will sometimes appear if a less-than or greater-than symbol gets improperly translated by the blog — those are display issues and I hope those are fixed.

There are a number of suggestions already in the article about how to make things stronger. The whole idea here (q.v. the title) is a Simple Wrapper. I’d recommend (again, as above) anybody who wants to use Aes to its full strength should not use a wrapper but should use the native .Net objects directly.

Hardcoding the key (as I did in the button click) is clearly a point of vulnerability (typically the calling app should acquire encryption keys from a trusted source via protected delivery), the key is explicit here for clarity, not security.

There is an infinite regression of how to make a given encryption stronger. A simple example is how the DES encryption, once it became trivially crackable, morphed into the triple-DES algorithm (basically a hack — just keep a-cryptin’ it.)

Please feel free to suggest stronger GetKey methods, password delivery modules, etc. in the comments.
-BlueBeetle

Comment on .Net Encryption simple AES wrapper by Bogdan Varlamov (a.k.a. Phantom Stranger)

Bogdan Varlamov (a.k.a. Phantom Stranger) — Wed, 20 May 2009 18:19:36 +0000

Michael, < is the less than sign; It should display the sign correctly now.

Comment on .Net Encryption simple AES wrapper by Gary Walker

Gary Walker — Fri, 24 Apr 2009 13:25:08 +0000

I\’ve tried viewing this page with IE6, FireFox 3, Opera 9 and Chrome. The code is partially obscured by the links on the right in every case.

Comment on .Net Encryption simple AES wrapper by Michael Yang

Michael Yang — Sat, 04 Apr 2009 01:03:10 +0000

I fixed above error message. thanks. But what\’s i

Thanks
Michael

Comment on .Net Encryption simple AES wrapper by Michael Yang

Michael Yang — Fri, 03 Apr 2009 23:19:39 +0000

Got error message:Error 5 The type or namespace name \’AesCryptoServiceProvider\’ could not be found (are you missing a using directive or an assembly reference?)
Could you help me ?

Thanks
Michael Yang

Comment on System.Threading.Timer Stops Firing in Windows Server 2003 SP1 by Chris Redekop

Chris Redekop — Sat, 28 Mar 2009 20:53:24 +0000

I am also having this problem in .NET 2.0 SP2 on Win2k3 SP2 x64….I can\’t find anything on the web about it tho….is there a hotfix available for .NET 2.0?

Comment on .Net Encryption simple AES wrapper by Johnny casey

Johnny casey — Thu, 12 Feb 2009 09:21:15 +0000

You have a serious bug in the GetKey function. Instead of:

kList.Add(kRaw[i % kRaw.Length]);

it should be:

kList.Add(kRaw[(i / 8 ) % kRaw.Length]);

Otherwise keying material of length 8 will only use the first letter.

I would also point out that while padding up to the full key length is a good idea, second guessing what the key should be can lead to incompatibilities.

And generating and prepending a random key would be a lot more secure.

Comment on System.Threading.Timer Stops Firing in Windows Server 2003 SP1 by Gerardo Palazuelos

Gerardo Palazuelos — Sun, 09 Nov 2008 10:00:20 +0000

Hi,
In 2006 we ran on this problem. Win 2003 Server SP1 and .NET 1.1. (shortly) I had 1 Windows Service that instantiates 1 “Adquisition” class 10+ times that implements 2 Timers each one. During the errors, we tested System.Threading.Timers and System.Timers.Timer; so we was having the problem with both Timer’s class.

After a while, we found the fix you’re referring (http://support.microsoft.com/?kbid=900822). We applied (240661_ENU_i386_zip.exe) and everythings works correctly for a long while!

Recently (1 month ago), Win 2003 Server SP2 was installed and we’re running in the same situation again. We used to have like 20 “Adquisition” classes before Win 2003 Server SP2 and everything was OK!… now we’re running in the same issues you described in your post: timer’s events stop firing (or as MS said: timer event is never signaled).

I’m going to talk with MS guys because my problem is on a production server and my application is prioritary (it’s crucial for the company)…

If anybody knows some fix/trick my contact is gpalazuelos at vai-ingdesi dot com.

Thanks!