Using the Internet itself as a computer, researchers have solved a mathematical problem with the unwitting assistance of machines in North America, Europe and Asia.The Notre Dame team exploited the Internet transmission control protocol (TCP). The TCP ensures accurate communication, using a “checksum” — a mathematical operation performed by sender and receiver. The two computers compare answers — if they differ, data has been corrupted in transit and they try again.

The researchers replaced the checksum (sent by their computer) with a potential solution to the problem they were trying to solve. They posted all the possible solutions to servers around the world. Each host sent only valid answers back to the parasite. Otherwise, it dropped the message.

Unfortunately (or not), the effort of communication currently outweighs the benefits of spreading the computational load.

Barabasi, A.-L., Freeh, V. W., Jeong, H. & Brockman, J. B.Parasitic computing. Nature, 412, 894 – 897, (2001).