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)


Atefeh Mashatan (#228)
Name Atefeh Mashatan
Personal Homepage
Topic of his/her doctorate. Message Authentication and Recognition Protocols Using Two-Chanel Cryptography.
Category cryptographic protocols
Keywords message authentication, ad hoc networks, manual authentication, two channel cryptography
Ph.D. Supervisor(s) Douglas Stinson, Edlyn Teske
Year of completion 2009

We propose a formal model for non-interactive message authentication protocols (NIMAPs) using two channels and analyze all the attacks that can occur in this model. Further, we introduce the notion of hybrid-collision resistant (HCR) hash functions. This leads to a new proposal for a NIMAP based on HCR hash functions. This protocol is as efficient as the best previous NIMAP while having a very simple structure and not requiring any long strings to be authenticated ahead of time.

We investigate interactive message authentication protocols (IMAPs) and pro- pose a new IMAP, based on the existence of interactive-collision resistant (ICR) hash functions, a new notion of hash function security. The efficient and easy-to- use structure of our IMAP makes it very practical in real world ad hoc network scenarios.

We also look at message recognition protocols (MRPs) and prove that there is a one-to-one correspondence between non-interactive MRPs and digital signature schemes with message recovery. Further, we look at an existing recognition proto- col and point out its inability to recover in case of a specific adversarial disruption. We improve this protocol by suggesting a variant which is equipped with a resynchronization process. Moreover, another variant of the protocol is proposed which self-recovers in case of an intrusion. Finally, we propose a new design for message recognition in ad hoc networks which does not make use of hash chains. This new design uses random passwords that are being refreshed in each session, as opposed to precomputed elements of a hash chain.

Last Change 2011-02-16 08:39:56
To provide an update on this entry, please click .

Contact: phds (at)

[ IACR home page ] [ IACR PhDs page ] © IACR