20110231913 | SYSTEM AND METHODS OF DETERMINING COMPUTATIONAL PUZZLE DIFFICULTY FOR CHALLENGE-RESPONSE AUTHENTICATION - Computational puzzles are parameterized by a difficulty variable which may be assigned based on at least one component from the group of components: time component, location component, reputation component, usage component, content component, and social networking component. For example, in one embodiment, the proof-of-work puzzle comprises a location component directed by the geographic location of the client that can be applied to any web transaction or application. One such application involves online ticket sales including those that employ purchasing robots. Another application involves accessing and using webmail. | 09-22-2011 |