That's the whole thing, don't get me wrong... What are reasonable client questions here? The client has to guess the file. So it may ask for something like a hash (as in sha1). Then the server answers yes/no, or gives some hint. So it probably involves some hashing algorithm. I'm not sure...

In reply to Re^4: Reverse download protocols by tomasz
in thread Reverse download protocols [solved] by tomasz

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