Outsourcing Modular Exponentiation in Cryptographic Web Applications

  • Pascal Mainini
  • Rolf HaenniEmail author
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10958)


Modern web applications using advanced cryptographic methods may need to calculate a large number of modular exponentiations. Performing such calculations in the web browser efficiently is a known problem. We propose a solution to this problem based on outsourcing the computational effort to untrusted exponentiation servers. We present several efficient outsourcing protocols for different settings and a practical implementation consisting of a JavaScript client library and a server application. Compared to browser-only computation, our solution improves the overall computation time by an order of magnitude.



We thank the anonymous reviewers for their thorough reviews. We appreciated their valuable comments and suggestions.


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Copyright information

© International Financial Cryptography Association 2019

Authors and Affiliations

  1. 1.Bern University of Applied SciencesBiel/BienneSwitzerland

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