[hashcash] Hashcash for Outlook 2003, preview version

  • From: "Simon Bohlin" <sesam@xxxxxxxxxxxxxx>
  • To: "'Adam Back'" <adam@xxxxxxxxxxxxxxx>
  • Date: Fri, 15 Jul 2005 15:35:10 +0200

Adam: I've joined the hashcash mailing list. For next time, can I send files
directly to the list?

Hi hashcash mailing list. I've got hashcash running in Outlook 2003.

Attached are two ZIP files: one containing the install files, the other with
VB.NET source code.
Please tell me how it works (or not).

If possible, don't consider this an official release; apply usual
disclaimers, etc.

Probably it only works in Outlook 2003.
I used a PIA (kind of .NET header file it seems) from Microsoft distrbutes
as O2003PIA.EXE, see link from here:

Some webpages claim you can make your own, but I couldn't figure out how.
If someone could contribute an "O2000PIA" that might be enough to get this 

The binaries are made for .NET framework 1.1.

If you have several Outlook plugins that also listen to the Application
ItemSend event, that might mask the event from either of them. I don't know

The current package (050714) uses a COM-automation library "Outlook
Redemption" to create the hashcash headers. It can be bought ($199) or
gratis for development use. Get it here:

MapiToolkit, a GPL:ed package in C++ from sourceXtreme, could replace
Redemption in adding headers. That would force a GPL:ed plugin. This might
limit the spreading of hashcash -- I'd prefer some more liberal licenses.
Included Hashcash.dll is under CPL so that is no problem. Can you see any
other practical problems with choosing GPL?

I look at http://spambayes.sf.net which contains well tested python plugin
code. But I don't know how to use MAPI in pyton.

There are more source code snippets laying around for solving the issue of
interfacing with "Extended MAPI" or "MAPI 1.0" to add headers.

I just experimented a bit with a C# implementation. (My first own
copy-pasted C# code!) VC++ might follow... :-)

Have fun!
/Simon Bohlin

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