The SPEKE Protocol Revisited
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.
KeywordsShared Secret Mutual Authentication Impersonation Attack Parallel Session Internet Draft
Unable to display preview. Download preview PDF.
- 1.Barker, E., Johnson, D., Smid, M.: Recommendation for pair-wise key establishment schemes using discrete logarithm cryptography (revised), NIST Special Publication 800-56A (March 2007), http://csrc.nist.gov/publications/nistpubs/800-56A/SP800-56A_Revision1_Mar08-2007.pdf
- 2.Bellovin, S., Merritt, M.: Encrypted Key Exchange: password-based protocols secure against dictionary attacks. In: Proceedings of the IEEE Symposium on Research in Security and Privacy (May 1992)Google Scholar
- 5.Entrust TruePass Product Portfolio: Strong Authentication, Digital Signatures and end-to-end encryption for the Web Portal, Technical Overview, Entrust Inc. (July 2003), http://www.entrust.com/wp-content/uploads/2013/05/entrust_truepass_tech_overview.pdf
- 6.BlackBerry Bridge App and BlackBerry PlayBook Tablet, Security Technical Overview - Version 2.0, Research in Motion Ltd. (February 2012), Available online through Blackberry Knowledge Base at http://btsc.webapps.blackberry.com/btsc/microsites/searchEntry.do
- 10.IEEE P1363 Working Group, P1363.2: Standard Specifications for Password-Based Public-Key Cryptographic Techniques. Draft available at http://grouper.ieee.org/groups/1363/
- 11.International Standard on Information Technology, Security Techniques, Key Management, Part 4: “Mechanisms based on week secrets”, ISO/IEC 11770-4:2006Google Scholar