To this end, we introduce Oblivious PAKE (O-PAKE), a general compiler for a large class of PAKE protocols, allowing a client that shares one password with a server to use a set of passwords within one PAKE session, which succeeds if and only if one of those input passwords matches the one stored on the server side. The term ``oblivious'' is used to emphasize that no information about non-matching passwords input by the client is made available to the server, which contrasts for instance to the aforementioned TLS-based approach, where any tried password is disclosed to the server. The $O(1)$ bound on the server side is obtained in our O-PAKE compiler using special processing techniques for the messages of the input PAKE protocol. We prove security of the O-PAKE compiler under standard assumptions using the latest variant of the popular game-based PAKE model by Bellare, Rogaway, and Pointcheval (Eurocrypt 2000). We identify the requirements that PAKE protocols must satisfy in order to suit the compiler and give two concrete O-PAKE protocols based on existing PAKE schemes. Both protocols are implemented and the analysis of their performance attests to the practicality of the compiler.
The use of O-PAKE further eliminates another practical problem with password-based authentication on the Web in that users no longer need to remember the actual association between their frequently used passwords and corresponding servers and can try several of them in one execution without revealing the entire set to the server.Category / Keywords: cryptographic protocols / Password Based Authenticated Key Exchange Publication Info: Not published yet Date: received 1 Mar 2013, last revised 4 Mar 2013 Contact author: f kiefer at surrey ac uk Available format(s): PDF | BibTeX Citation Version: 20130305:125136 (All versions of this report) Discussion forum: Show discussion | Start new discussion