On the Security of Jhanwar-Barua Identity-Based Encryption Scheme

  • Adrian G. SchiporEmail author
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11359)


In [3], Jhanwar and Barua presented an improvement of the Boneh-Gentry-Hamburg (BGH) scheme. In addition to reducing the time complexity of the algorithm to find a solution of the equation \(ax^2+Sy^2\equiv 1 \bmod n\), their scheme reduces the number of equations to be solved by combining existing solutions. In [2], Susilo et al. extended the Jhanwar-Barua scheme, reducing more the number of equations to be solved. This paper presents a security flaw that appears in both schemes and shows that they are not IND-ID-CPA secure.



I wish to thank to my supervisor, Prof. Dr. Ferucio Laurenţiu Ţiplea, for helping me by deducing the property (2) from the Sect. 3 (the case when R is not a quadratic residue), after the practical tests told us that the property should hold.


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Authors and Affiliations

  1. 1.Department of Computer Science“Al. I. Cuza” University of IașiIașiRomania

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