Learning to impersonate

Consider Alice, who is interacting with Bob. Alice and Bob have some shared secret which helps Alice identify Bob-impersonators. Now consider Eve, who knows Alice and Bob, but does not know their shared secret. Eve would like to impersonate Bob and "fool" Alice without knowing the secret. If Eve is computationally unbounded, how long does she need to observe Alice and Bob interacting before she can successfully impersonate Bob? What is a good strategy for Eve in this setting? If Eve runs in polynomial time, and if there exists a one-way function, then it is not hard to see that Alice and Bob may be "safe" from impersonators, but is the existence of one-way functions an essential condition? Namely, if one-way functions do not exist, can an efficient Eve always impersonate Bob? In this work we consider these natural questions from the point of view of Ever, who is trying to observe Bob and learn to impersonate him. We formalize this setting in a new computational lea...

• Type: Conference
• Year: 2006
• Where: ICML
• Authors: Moni Naor, Guy N. Rothblum
• Keywords: Efficient Bob, Efficient Eve, ICML 2006, Impersonate Bob, Machine Learning