Covert Distributed Processing with Computer Viruses

Computer viruses can be used by their authors to harness the resources of infected machines for the author's computation. By doing so without the permission or knowledge of the machine owners, viruses can be used to perform covert distributed processing. We outline the class of problems for which covert distributed processing can be used. A brute-force attack on cryptosystems is one such problem, and we give estimates of the time required to complete such an attack covertly.