Lewko-Waters Unbounded HIBE implementation

[Nikos Fotiou]

Hi,

I have implemented the "A. Lewko, B. Waters Unbounded HIBE and Attribute-Based Encryption" scheme. In particular its modification for prime order groups.

Original scheme: "A. Lewko, B. Waters Unbounded HIBE and Attribute-Based Encryption"

Published in: Advances in Cryptology - EUROCRYPT 2011, Springer Berlin/Heidelberg, 2011

Available from: http://eprint.iacr.org/2011/049

Modified scheme for prime order groups: "A. Lewko Tools for Simulating Features of Composite Order Bilinear Groups in the Prime Order Setting" Section B.3

Published in: Advances in Cryptology - EUROCRYPT 2012, Springer Berlin/Heidelberg, 2012

Available from: http://eprint.iacr.org/2011/490

Source code of the implementation:

https://github.com/nikosft/HIBE_LW11

Regards,

Nikos Fotiou

[José Miguel López Becerra]

That is awsome, thanks for sharing. 

Can I ask you a simple question?

I am about to implement a KP-ABE to use it as searchable encryption (then attributes must be hidden). For my implementation I need "composite order billinear maps". Do you know if that is supported by charm? One year ago I implemented Boneh's PEKS, then billinear maps of prime order are supported by Charm, but I am not sure about billinear maps of composite order. 

I ask you because I see that your implementation of HIBE requires composite order billinear maps, you need N = p1*p2*p3

Any help would be sincerely appreciated. 

Thank you

[José Miguel López Becerra]

I got a bit confused. If I understood right, you did not need composite order bilinear maps for your implementation due to "Lewko Tools..." right?

Cheers, 

--José

[Nikos Fotiou]

Hi,
Indeed I did not need composite order maps. I far as I know charm-crypto has only prime order curves