This page intentionally left blank CAMBRIDGE TRACTS IN MATHEMATICS GeneralEditors B.BOLLOBAS, F.KIRWAN, P.SARNAK, C.T.C.WALL 132 Character Sums with Exponential Functions and their Applications SergeiV.Konyagin IgorE.Shparlinski MoscowStateUniversity MacquarieUniversity Character Sums with Exponential Functions and their Applications The Pitt Building, Trumpington Street, Cambridge, United Kingdom The Edinburgh Building, Cambridge CB2 2RU, UK 40 West 20th Street, New York, NY 10011-4211, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia Ruiz de Alarcón 13, 28014 Madrid, Spain Dock House, The Waterfront, Cape Town 8001, South Africa http://www.cambridge.org ©Cambridge University Press 2004 First published in printed format 1999 ISBN 0-511-04036-9 eBook (netLibrary) ISBN 0-521-64263-9 hardback Contents Preface pagevii Acknowledgement viii Part one: Preliminaries 1 1 Introduction 3 2 NotationandAuxiliaryResults 8 Part two: Bounds of Character Sums 11 3 BoundsofLongCharacterSums 13 4 BoundsofShortCharacterSums 26 5 BoundsofCharacterSumsforAlmostAllModuli 31 6 BoundsofGaussianSums 37 Part three: Multiplicative Translations of Sets 47 7 MultiplicativeTranslationsofSubgroupsofF∗ 49 p 8 MultiplicativeTranslationsofArbitrarySetsModulo p 59 Part four: Applications to Algebraic Number Fields 63 9 RepresentativesofResidueClasses 65 10 CyclotomicFieldsandGaussianPeriods 76 Part five: Applications to Pseudo-Random Number Generators 89 11 PredictionofPseudo-RandomNumberGenerators 91 12 CongruentialPseudo-RandomNumberGenerators 99 Part six: Applications to Finite Fields 107 13 SmallmthRootsModulo p 109 14 SupersingularHyperellipticCurves 115 15 DistributionofPowersofPrimitiveRoots 131 Part seven: Applications to Coding Theory and Combinatorics 141 16 DifferenceSetsinVp 143 17 DimensionofBCHCodes 148 18 AnEnumerationProbleminFiniteFields 154 Bibliography 157 Index 163 v Preface In this book, we consider various questions related to the distribution of integer powers gx of some integer g > 1 modulo a prime number p with gcd(g,p) = 1. Possible applications where such results play a central role include, but are not limited to, linear congruential pseudo-random number generators,algebraicnumbertheory,thetheoryoffunctionfieldsoverafinite field,complexitytheory,cryptography,andcodingtheory. We also consider similar questions in a more general setting related to the distribution of elements of a finitely generated multiplicative group V withr generatorsinanalgebraicnumberfieldKofdegreenoverQmoduloaninteger idealq. vii Acknowledgement The authors are grateful to Alf van der Poorten for his help, support and valuableadvice. The authors also wish to thank Hugh Montgomery and Martin Tompa for ahelpfuldiscussionoftheproblemsconsideredinChapter15andFrancesco Pappalardiforinformationabouthisresult[72]andmanyfruitfuldiscussions of some problems. The authors are thankful to Roger Heath-Brown for providing us with some of his unpublished results. Corey Powell kindly providedapreliminaryversionof[73]. The authors would like to thank Gang Yu who helped them to find some mistakesinapreliminaryversionofChapter6. The research of the first author has been supported by the Grant DMS 9304580fromtheNSF. The research of the second author has been supported in part by the GrantA69700294oftheAustralianResearchCouncil. viii