Deny certain words

[Grozdan]

Hi,

Somehow my server gets hit by torrent requests which look like this:

GET /?info_hash=.....

after the = come long strings of seemingly random hashes torrent
clients are looking for.

I'd like to deny all such requests so would like if someone could
provide me how to deny everything (and including) ?info_hash=

I've looked all over the net at similar examples but all I tried thus
far didn't work

Thanks :)

-- 
Yours truly