Invited papers -- Putting the Hodge and Tate Conjectures to the Test -- Curves of Genus 3 with a Group of Automorphisms Isomorphic to S3 -- Learning with Errors over Rings -- Lattices and Spherical Designs -- Fixed Points for Discrete Logarithms -- Contributed papers -- Explicit Coleman Integration for Hyperelliptic Curves -- Smallest Reduction Matrix of Binary Quadratic Forms -- Practical Improvements to Class Group and Regulator Computation of Real Quadratic Fields -- On the Use of the Negation Map in the Pollard Rho Method -- An O(M(n) logn) Algorithm for the Jacobi Symbol -- New Families of ECM Curves for Cunningham Numbers -- Visualizing Elements of Sha[3] in Genus 2 Jacobians -- On Weil Polynomials of K3 Surfaces -- Class Invariants by the CRT Method -- Short Bases of Lattices over Number Fields -- On the Complexity of the Montes Ideal Factorization Algorithm -- Congruent Number Theta Coefficients to 1012 -- Pairing the Volcano -- A Subexponential Algorithm for Evaluating Large Degree Isogenies -- Huff’s Model for Elliptic Curves -- Efficient Pairing Computation with Theta Functions -- Small-Span Characteristic Polynomials of Integer Symmetric Matrices -- Decomposition Attack for the Jacobian of a Hyperelliptic Curve over an Extension Field -- Factoring Polynomials over Local Fields II -- On a Problem of Hajdu and Tengely -- Sieving for Pseudosquares and Pseudocubes in Parallel Using Doubly-Focused Enumeration and Wheel Datastructures -- On the Extremality of an 80-Dimensional Lattice -- Computing Automorphic Forms on Shimura Curves over Fields with Arbitrary Class Number -- Improved Primality Proving with Eisenstein Pseudocubes -- Hyperbolic Tessellations Associated to Bianchi Groups.

This book constitutes the refereed proceedings of the 9th International Algorithmic Number Theory Symposium, ANTS 2010, held in Nancy, France, in July 2010. The 25 revised full papers presented together with 5 invited papers were carefully reviewed and selected for inclusion in the book. The papers are devoted to algorithmic aspects of number theory, including elementary number theory, algebraic number theory, analytic number theory, geometry of numbers, algebraic geometry, finite fields, and cryptography.