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The SPEKE Protocol Revisited

Lookup NU author(s): Professor Feng Hao, Dr Siamak Fayyaz Shahandashti



The SPEKE protocol is commonly considered one of the classic Password Authenticated Key Exchange (PAKE) schemes. It has been included in international standards (particularly, ISO/IEC 11770-4 and IEEE 1363.2) and deployed in commercial products (e.g., Blackberry). We observe that the original SPEKE specification is subtly different from those defined in the ISO/IEC 11770-4 and IEEE 1363.2 standards. We show that those differences have critical security implications by presenting two new attacks on SPEKE: an impersonation attack and a key-malleability attack. The first attack allows an attacker to impersonate a user without knowing the password by engaging in two parallel sessions with the victim. The second attack allows an attacker to manipulate the session key established between two honest users without being detected. Both attacks are applicable to the original SPEKE scheme, and are only partially addressed in the ISO/IEC 11770-4 and IEEE 1363.2 standards. We highlight deficiencies in both standards and suggest concrete changes.

Publication metadata

Author(s): Hao F, Shahandashti SF

Publication type: Report

Publication status: Published

Series Title: School of Computing Science Technical Report Series

Year: 2014

Pages: 13

Print publication date: 01/09/2014

Report Number: 1434

Institution: School of Computing Science, University of Newcastle upon Tyne

Place Published: Newcastle upon Tyne