Abelian Varieties with Prescribed Embedding Degree

We present an algorithm that, on input of a CM-field $K$, an integer $k\ge1$, and a prime $r \equiv 1 \bmod k$, constructs a $q$-Weil number \pi \in \O_K corresponding to an ordinary, simple abelian variety $A$ over the field \F of $q$ elements that has an \F-rational point of order $r$ and embedding degree $k$ with respect to $r$. We then discuss how CM-methods over $K$ can be used to explicitly construct $A$.Comment: to appear in ANTS-VII

Abelian varieties in pairing-based cryptography

We study the problem of the embedding degree of an abelian variety over a finite field which is vital in pairing-based cryptography. In particular, we show that for a prescribed CM field $L$ of degree $\geq 4$, prescribed integers $m$, $n$ and any prime $l\equiv 1 \pmod{mn}$, there exists an ordinary abelian variety over a finite field with endomorphism algebra $L$, embedding degree $n$ with respect to $l$ and the field extension generated by the $l$-torsion points of degree $mn$ over the field of definition. We also study a class of absolutely simple higher dimensional abelian varieties whose endomorphism algebras are central over imaginary quadratic fields.Comment: Typos fixe

A CM construction for curves of genus 2 with p-rank 1

We construct Weil numbers corresponding to genus-2 curves with $p$-rank 1 over the finite field \F_{p^2} of $p^2$ elements. The corresponding curves can be constructed using explicit CM constructions. In one of our algorithms, the group of \F_{p^2}-valued points of the Jacobian has prime order, while another allows for a prescribed embedding degree with respect to a subgroup of prescribed order. The curves are defined over \F_{p^2} out of necessity: we show that curves of $p$-rank 1 over \F_p for large $p$ cannot be efficiently constructed using explicit CM constructions.Comment: 19 page