International Association for Cryptologic Research

International Association
for Cryptologic Research

IACR News item: 31 May 2015

Suvradip Chakraborty, Srinivasan Raghuraman, C. Pandu Rangan
ePrint Report ePrint Report
In this paper, we present a single round two-party attribute-based authenticated key exchange protocol. Since pairing is a costly operation and the composite order groups must be very large to ensure security, we focus on pairing free protocols in prime order groups. We propose a new protocol that is pairing free, working in prime order group and having tight reduction to Strong Diffie Hellman (SDH) problem under the Attribute-based CK model which is a natural extension of the CK model for the public key setting. Our proposed attribute based authenticated key exchange protocol (ABAKE) also does not depend on any underlying attribute based encryption schemes unlike the previous solutions for ABAKE. Ours is the first scheme that removes this restriction. Thus, the first major advantage is that smaller key sizes are sufficient to achieve comparable security. Our scheme has several other advantages. The major one being the capability to handle active adversaries. Most of the previous Attribute-Based authenticated key exchange protocols can offer security only under passive adversaries. Our protocol recognizes the corruption by an active adversary and aborts the process. In addition to this property, our scheme satisfies other security properties that are not covered by CK model such as forward secrecy, key compromise impersonation attacks and ephemeral key compromise impersonation attacks.

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