Cryptanalysis and Improvement of a k-out-of-n Oblivious Transfer Protocol

In this article, the authors cryptanalyze a k-out-of-n oblivious transfer protocol proposed in [12 Jain , A. , and C. Hari . 2010 . A New Efficient Protocol for k-out-of-n Oblivious Transfer , Cryptologia , 34 ( 4 ): 282 – 290 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]]. Their protocol is one of the most efficient k-out-of-n oblivious transfer protocols and is directly built from a 1-out-of-n oblivious transfer protocol. However, their analysis shows that the proposed k-out-of-n oblivious transfer protocol is insecure, though the primitive 1-out-of-n oblivious transfer protocol is secure. The weakness is that with high probability the receiver in their protocol can get all n secret messages encrypted by the sender. Finally, they fix the serious flaw and introduce an improved k-out-of-n oblivious transfer protocol without increasing any cost.