International Association for Cryptologic Research

Ph.D. Database

The aim of the IACR Ph.D. database is twofold. On the first hand, we want to offer an overview of Ph.D. already completed in the domain of cryptology. Where possible, this should also include a subject classification, an abstract, and access to the full text. On the second hand, it deals with Ph.D. subjects currently under investigation. This way, we provide a timely map of contemporary research in cryptology. All entries or changes need to be approved by an editor. You can contact them via phds (at)


Jonathan Katz (#440)
Name Jonathan Katz
Personal Homepage
Institution Columbia University
Topic of his/her doctorate. Efficient Cryptographic Protocols Preventing Man-in-the-Middle Attacks
Category cryptographic protocols
Ph.D. Supervisor(s) Moti Yung, Zvi Galil
Year of completion 2002

In the analysis of many cryptographic protocols, it is useful to distinguish two classes of attacks: passive attacks in which an adversary eavesdrops on messages sent between honest users, and active attacks in which --- in addition to eavesdropping --- the adversary inserts, deletes, or arbitrarily modifies messages sent from one user to another. Active attacks are not well characterized and precise modeling has been difficult. Few techniques exist for dealing with active attacks, and designing practical protocols secure against such attacks remains a challenge.

This dissertation considers active attacks in a variety of settings and provides new, provably secure protocols preventing such attacks. Proofs of security are in the standard cryptographic model and rely on well-known cryptographic assumptions. The protocols presented here are efficient and practical, and may find application in real-world systems.

E-Mail Address jkatz (at)
Last Change 2011-07-21 16:04:19
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Jonathan Katz's Students

Chiu Yuen Koo - Studies on Fault-Tolerant Broadcast and Secure Computation (cryptographic protocols)
Dominique Schroeder - On the Complexity of Blind Signatures (foundations)
S. Dov Gordon - On Fairness in Secure Computation (cryptographic protocols)
S. Dov Gordon - On Fairness in Secure Computation (cryptographic protocols)

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