Marcela Melara will present her MSE thesis talk on Thursday April 17 at 2PM in Room 402. Her committee is: Ed Felten, advisor and Michael Freedman, reader. Everyone is invited to attend her talk. Her abstract follows below. --------------------------- Abstract: As a foundation for securing Internet communication, today’s public-key infrastructures attempt to certify that the “correct” principal owns a name and possesses a corresponding public key. Yet these assertions are not machine-verifiable, and their correctness can be and has been broken by error, malice, or external (and sometimes legal) coercion. Rather than focus on the “correctness” of name ownership, we argue that ensuring the continuity of that ownership, as defined by the binding of a name to a public key, is necessary and often sufficient for secure communication. To this end, we have designed CONIKS, a key management system that ensures online identity providers maintain and respond with valid bindings from names to cryptographic keys, even without users managing (or seeing) those keys. If providers disseminate invalid bindings or equivocate by presenting different bindings to different users, parties quickly detect this misbehavior and can publish irrefutable proof of this equivocation. The cryptographic mechanisms employed by CONIKS are highly efficient, supporting an Internet environment of millions of providers, any of which may have users in the billions. Our prototype Off-the-Record chat service, ConiksChat, demonstrates that one can achieve high usability while preserving the security and privacy of online communications.