Improved Efficiency of a Linearly Homomorphic Cryptosystem

  • Parthasarathi DasEmail author
  • Michael J. JacobsonJr.
  • Renate Scheidler
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11445)


We present an extended version of the Castagnos and Laguillaumie linearly homomorphic cryptosystem [5] in which the non-maximal imaginary quadratic order is allowed to have conductor equal to a product of prime powers as opposed to a single prime. Numerical results obtained with an optimized C implementation demonstrate that this variation improves performance when large messages and exponents are used. When compared to the cryptosystems of Paillier [11] and Bresson et al. [3] at the same security levels, the basic version of Castagnos and Laguillaumie is the fastest at high security levels for small messages.


Linearly homomorphic encryption Public key cryptography Ideal class group Electronic voting Encryption switching protocol 


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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Parthasarathi Das
    • 1
    Email author
  • Michael J. JacobsonJr.
    • 1
  • Renate Scheidler
    • 2
  1. 1.Department of Computer ScienceUniversity of CalgaryCalgaryCanada
  2. 2.Department of Mathematics and StatisticsUniversity of CalgaryCalgaryCanada

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