Comparing Invariants for Class Fields of Imaginary Quadratic Fields

  • Andreas Enge
  • François Morain
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2369)


Class fields of imaginary quadratic number fields can be constructed from singular values of modular functions, called class invariants. From a computational point of view, it is desirable that the associated minimal polynomials be small. We examine different approaches to measure the size of the polynomials. Based on experimental evidence, we compare two families of class invariants suggested in the literature with respect to these criteria. Our results lead to more efficient constructions of elliptic curves for cryptography or in the context of elliptic curve primality proving (ECPP).


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Copyright information

© Springer-Verlag Berlin Heidelberg 2002

Authors and Affiliations

  • Andreas Enge
    • 1
  • François Morain
    • 1
  1. 1.Laboratoire d’Informatique (CNRS/UMR 7650)Ecole polytechniquePalaiseau CedexFrance

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