简介:AlinearizationattackontheKeyStreamGenerator(KSG)ofthemodifiedE0algorithmproposedbyHermelin[ProceedingsofICISC'99,SpringerLNCS1787,2000,17-29]isgiveninthispaper.TheinitialvaluecanberecoveredbyalinearizationattackwithO(260.52)operationsbysolvingaSystemofLinearEquations(SLE)withatmost220.538unknowns.FrederikArmknecht[CryptologyePrintArchive,2002/191]proposedalinearizationattackontheKSGofE0algorithmwith0(270.341)operationsbysolvinganSLEwithatmost224.056unknowns,sothemodificationproposedbyHermelinreducestheabilityofE0toresistthelinearizationattackbycomparingwiththeresultsofFrederikAnnknecht.
简介:Atomicityisnecessaryforreliableandsecureelectroniccommercetransactionandtoguaranteetheparticipants'interests.Anatomicandefficiente-cash(electroniccash)transactionprotocolbasedontheclassicale-cashschemeispresented.Thedeliveryofdigitalgoodsisincorporatedintotheprocessofpaymentintheprotocol.Apartfromensuringallthreelevelsofatomicity,thenovelprotocolfeatureshighefficiencyandpracticabilitywithunfavorablestrongassumptionremoved.Furthermore,theproposedprotocolprovidesnon-repudiationproofsforanyfuturedisputes.Atlast,analysisoftheatomicityandefficiencyisillustrated.
简介:Electronictransactionthroughe-paymentprotocolwillgrowtremendousinthecomingyears.Inthisarticle,byconverselyusingblindsignature,theauthorsproposeafairelectronicpaymentschemeforelectroniccommerce,whichcanensuretwoparticipants’rightsimultaneouslyinelectronictransactionprocess.Thisschemeisdifferentfromotherexistingschemesanditdoesnotrequirestrongtrustrelationbetweencustomerandmerchant.Inthescheme,asemi-trustedthirdparty(S-TTP)isinvolvedtoprovideafaircommerceenvironment.TheS-TTPtakespartintheprotocolon-lineandnosecureinformationaboutthebusinessisleaked.Moreover,theparticipantsdonotneedtoregistertoS-TTP.Thisschemedoesnotrequireinterventionofathirdpartyincaseofdispute,ifoneusercheatsorsimplycrashes.