hello Here is the problem: how to make sure that an untrusted computer really run the code you ask him to run. Practically, we can take the example of the RC5 contest. If I ask an untrusted computer to search for the key in a particular sub-keyspace, how can I make sure that this machine really looked for the key, and that it doesn't just say "the key is not in this block, give me another block" just to get higher in the stats... I've heard about smartcards being helped by ATMs, so maybe this could be a direction to look into... Any pointer, info, help, ... very appreciated alex -- \\-----------------------------------------------------------\\ // Alexandre Maret -- Linux : The choice of a GNU generation // \\ amaret@infomaniak.ch -- http://www.infomaniak.ch/~amaret \\ //-----------------------------------------------------------//