Utilizing The Power of Human Cycles ( Thesis Proposal )

We propose several novel techniques for exploiting the computational abilities (or “cycles”) of humans. One technique is captcha, an automated test that humans can pass but that current computer programs cannot. captchas take advantage of the power of human cycles to differentiate people from computers. We propose several constructions of captchas and we show that they have many applications in practical security — the results of our work, for instance, are used by Yahoo to ensure that only humans obtain free email accounts. We also introduce techniques to harvest human cycles for the purpose of solving large-scale problems that computers cannot yet solve. There many people on the internet constantly doing things that computer programs cannot currently do: understanding images and sentences, chatting, passing captcha tests, etc. We show how to “reuse” or “steal” such human cycles to do useful work. We introduce a game, The ESP Game, that is fun — many people play over 40 hours a week! — and when people play they help determine the contents of images on the Web by providing meaningful labels for them. If the game is played as much as other popular online games, all images on the Web can be labeled in just a few weeks. Attaching proper labels to all images on the Web would allow for more accurate image search engines, would improve the accessibility of Web sites (by providing descriptions of images to visually impaired individuals), and would help Web browsers block