The greatest difficulty in getting millions of computers to work on a brute-force attack is convincing millions of computer owners to participate. You could ask politely, but thatís time consuming and they might say no. We could try breaking into their machines, but thatís even more time consuming and we might get arrested, we could also use a computer virus to spread the cracking program more efficiently over many computers as possible.
This is a particularly insidious idea, first presented by active attack, passive attack, brute force attack & various cryptographic attacks. The attacker writes and letís chooses a computer virus. This virus doesnít reformat the hard drive or delete files; it works on a brute force cryptanalysis problem whenever the computer is idle. Various studies have shown that microcomputer are idle between 70 and 90 percent of the time, so the virus should not have any trouble finding time to work on its task. If it is otherwise benign, it might even escape notice while it does its work.
Eventually, one machine will stumble on the correct key. At this point there are two ways of proceeding. First, the virus could spawn a different virus. It wouldnít do anything but reproduce and delete any copies of the cracking virus it finds but would contain the information about the correct key. This new virus would simply propagate through the computer world (.i.e. Intranet, Extranet & Internet) until it lands on the computer of the person who wrote the original virus.
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