# Equivalences between elliptic curves and real quadratic congruence function fields

Journal de théorie des nombres de Bordeaux (1997)

- Volume: 9, Issue: 1, page 75-95
- ISSN: 1246-7405

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topStein, Andreas. "Equivalences between elliptic curves and real quadratic congruence function fields." Journal de théorie des nombres de Bordeaux 9.1 (1997): 75-95. <http://eudml.org/doc/247991>.

@article{Stein1997,

abstract = {In 1994, the well-known Diffie-Hellman key exchange protocol was for the first time implemented in a non-group based setting. Here, the underlying key space was the set of reduced principal ideals of a real quadratic number field. This set does not possess a group structure, but instead exhibits a so-called infrastructure. More recently, the scheme was extended to real quadratic congruence function fields, whose set of reduced principal ideals has a similar infrastructure. As always, the security of the protocol depends on a certain discrete logarithm problem (DLP). In this paper, we show that for real quadratic congruence function fields of genus one, i.e. elliptic congruence function fields, this DLP is equivalent to the DLP for elliptic curves over finite fields. We present the explicit corresponce between the two DLPs and prove some properties which have no analogues for real quadratic number fields. Furthermore, we show that for elliptic congruence function fields, the set of reduced principal ideals is even “closer” to a group than in the general case, but still fails to be a group.},

author = {Stein, Andreas},

journal = {Journal de théorie des nombres de Bordeaux},

keywords = {real quadratic congruence function field; continued fractions; reduced ideals; elliptic curves; discrete logarithm; Diffie-Hellman key exchange; discrete logarithm problem; real quadratic congruence function fields},

language = {eng},

number = {1},

pages = {75-95},

publisher = {Université Bordeaux I},

title = {Equivalences between elliptic curves and real quadratic congruence function fields},

url = {http://eudml.org/doc/247991},

volume = {9},

year = {1997},

}

TY - JOUR

AU - Stein, Andreas

TI - Equivalences between elliptic curves and real quadratic congruence function fields

JO - Journal de théorie des nombres de Bordeaux

PY - 1997

PB - Université Bordeaux I

VL - 9

IS - 1

SP - 75

EP - 95

AB - In 1994, the well-known Diffie-Hellman key exchange protocol was for the first time implemented in a non-group based setting. Here, the underlying key space was the set of reduced principal ideals of a real quadratic number field. This set does not possess a group structure, but instead exhibits a so-called infrastructure. More recently, the scheme was extended to real quadratic congruence function fields, whose set of reduced principal ideals has a similar infrastructure. As always, the security of the protocol depends on a certain discrete logarithm problem (DLP). In this paper, we show that for real quadratic congruence function fields of genus one, i.e. elliptic congruence function fields, this DLP is equivalent to the DLP for elliptic curves over finite fields. We present the explicit corresponce between the two DLPs and prove some properties which have no analogues for real quadratic number fields. Furthermore, we show that for elliptic congruence function fields, the set of reduced principal ideals is even “closer” to a group than in the general case, but still fails to be a group.

LA - eng

KW - real quadratic congruence function field; continued fractions; reduced ideals; elliptic curves; discrete logarithm; Diffie-Hellman key exchange; discrete logarithm problem; real quadratic congruence function fields

UR - http://eudml.org/doc/247991

ER -

## References

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