For the first time I used a [magnet link](http://en.wikipedia.org/wiki/Magnet_URI_scheme). Curious about how it works, I looked up the specs and didn't find any answers. The wiki says `xt` means "exact topic" and is followed by the format (`btih` in this case) with a SHA1 hash. I saw base32 mentioned, knowing it's 5 bits per character and 32 characters, I found it holds exactly 160bits, which is exactly the size of the SHA1.

There's no room for an IP address or anything, it's just a SHA1. So how does the BitTorrent client find the actual file? I turned on URL Snooper to see if it visits a page (using TCP) or does a lookup or the like, but nothing happened. I have no idea how the client finds peers. How does this work?

Also, what is the hash of? Is it a hash of an array of all the file hashes together? Maybe it's a hash of the actual torrent file required (stripping certain information)?

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In a VM, I tried a magnet link with uTorrent (which was freshly installed) and it managed to find peers. Where did the first peer come from? It was fresh and there were no other torrents.