Calculate Torrent Info_Hash?

[nomaam]

Hello:

I am working with VB.NET, framework 2.0 and working in a windows form.

I am trying to calculate the info_hash of a torrent file. From what I have read it is a 20 byte SHA1 value of the file's metadata.

However, I am at a loss at how to calculate it as I am not sure on the exact portion of the file I should be working with. Currently the two main references I am using are as follows:

Torrent file info: http://www.bittorrent.org/protocol.html

Calculating SHA1 hash: http://www.obviex.com/samples/hash.aspx

Can anyone give me some advise on how to get this done?

Thanks.