邹锦沛许志光姚兆明香港大学资讯保安及密码学

1DrsKPChow,LucasHui,SMYiuCenterforInformationSecurity&Cryptography(CISC)邹锦沛,许志光,姚兆明香港高校资讯保安及密码学探讨中心InformationSecurityanddigitalforensicsresearchinCS,HKUResearchDirectionsinCISC探讨项目2ComputerForensicsresearchSecurityandcryptographyresearchCryptographicprimitives加密基元Infrastructure(Identity-based;PKI-basedetc)anddifferentsecurityModelsSignature/encryptionschemes…..Leakageresilience泄漏的韧性……….Cryptographicprotocol(密码协议)VANETs(Vehicularadhocnetwork)车辆随意网路Smart(power)gridsystem智能电网系统Databasesystem数据库系统(e.g.dataminingwithprivacy数据挖掘隐私问题)Anonymousauthentication(credential)indiscussiongroup讨论组匿名身份验证(凭据)……..Applications&implementation应用与实现Hybrid(software+hardwaretoken)混合系统(软件+硬件密钥)GPU(图形处理单元卡)………3(1)LeakageResilience(泄漏的韧性)OldBelief:Encryptionprotectsyourdatawellandtheattackerhasnoinformation(noteven1bit)aboutyoursecretkey(e.g.passwords).4Impact:oldsecurityschemesarenotguaranteedtobesecure!!ThisisWRONG!!The“new”assumption:Attackermaygetpartialinformationaboutthesecretkey.E.g.MeasurerunningtimeofCPU,temperatureofCPU,soundofthekeyboardstroke,etc…Byrestrictingthepoweroff,werestricthowmuchinformationisleaked.E.g.foutputsxbitsonly,withx<key(password)length.5ThemodelToformalizetheseattacks,wemodelitasanefficientlycomputedleakagefunctionfwhichrepresentshowmuchleakageinformationcanbeobtainedbytheattacker.Selectedpublication:“ID-basedencryptionschemeoncontinualauxiliaryleakagemodel”,Eurocrypt2012.CanwestillprovethatschemeAisstillsecure?SecurityschemeAf(key)allothermsgs/infoAttacker(2)DynamicBirthmarkGenerationforJavascript(JavaScript动态软件胎记)QuestionAddressed:Given2JavaScriptprograms,doesoneprogramcopytheother?[plagiarism?IPcourtcases:Softwarethefts?]OnemaychangethesourcecodeOurResearchApproach:Runthetwoprograms,aftersometime:Dumptheobjectsatthememory(heaparea)ofthetwoprograms.Thisisthebirthmarkoftheprograms(likebirthmarkofthepig)Ifthedatastructure(heapgraphinthiscase)ofthetwoprogramsaresimilar,oneislikelytobecopyingtheother.HeapGraphExample67SelectedpublicationsPreliminaryideas:“DynamicSoftwareBirthmarkforJavaBasedonHeapMemoryAnalysis”,CMS2011.“JSBiRTH:DynamicJavaScriptBirthmarkBasedontheRun-timeHeap”,COMPSAC2011.Amorematuremethodology:“Heapgraphbasedsoftwaretheftdetection”,IEEETransactiononInformationForensicsandSecurity(IEEETIFS)2012.8(3)AndroidsecurityDroidCheckerIssue:UnlikeApple’sAppstores,noscreeningprocessoftheappsbeingpublishedontheAndroidmarketPrivilegeescalationattack:TheappcanperformafunctionthatitisNOTsupposedtodo.Ourtechnique:identifyriskypathfromcontrol-flowgraph

DroidChecker:AnalyzingAndroidApplicationsforCapabilityLeak,ACMWiSec2012.1,179Androidappsscanned=>23foundtoberiskyAdobephotoshopexpress1.31:amaliciousappcanmakeuseofittoretrieveallemailcontactsofthephoneStillon-going……ResearchDirectionsinCISC探讨项目9ComputerForensicsresearchSecurityandcryptographyresearchCISC10Softwaretoolsdevelopment数字调查和取证:DESK(数字证据搜寻工具)BTM(也称为网线监察系统)拍卖现场监测互联网监控平台ResearchDigitalidentityprofiling(數碼特徵)Behaviorprofiling:互联网上罪犯的數碼特征Visualprofiling:數碼视觉特征Cybercrimemodel…..ComputerForensicsResearchGroup计算机取证

互联网罪犯的數碼特征

(digitalidentityprofiling)行为特徵(Behaviorprofiling)互联网上侵权罪犯的數碼特征互联网拍卖欺诈的數碼特征CISC11我们的探讨-數碼特征Inphysicalword,we(e.g.FBI)useitalotfor:同系列犯罪的调查，例如：性侵犯，凶杀，色情凶杀案网络犯罪有系列本质

(serialinnature):网络犯罪的系列本质允许罪犯行为的识别和常量分类(repeatinginnature重複性質)网上用户特性(preliminarystudy)网络身份与用户真实身份没有联系在互联网中可以特别简洁的隐藏个人真实身份和行为很多状况下，一个人拥有多个用户帐户判别一系列网络行为是否由一个用户引起还是多个用户涉及是很困难的13用戶数码特征分析根據每個用戶的張貼，計算一個特徵詞的權重向量(avectoroftheweightsoffeaturewords)Computingtheweightofafeatureword(t)w.r.f.auser(u)?TF-IDFweight(Saltonetal.)W(t,u)=TF(t,u)xlogU{u’Utu’}

Frequencyoftinu’spostingsTotalnumberofusers#ofusershavingtintheirpostingsFewerusershavetheword,theweightlargerAProfile(用戶数码特征)Userdow_jonesinuwantsCISC14FeaturewordWeight180后0.217612社民连0.143493五区0.125474泛民0.113575西九0.109836黄毓民0.086717功能组别0.084338总辞0.082969八十后0.0819410社民0.08126运用用戶数码特征進行預測CISC15這些discuss.hk論壇上的張貼,是不是uwants用戶dow_jones發布Example–UsersthataresimilarTobetrialusedbyHongKongPolice數碼相機SD卡案例相片1相片2相片3相片10相片11Jan2006Oct2006Time受害人說謊？?或是創建日期不正確!!Jan2007(犯罪行为)受害人的陈述书Dec2006(分手)17Jan2005相片8018Duetothetimelimit,maybewecanshareotherprojectsnexttime.Publications:IEEETransactions,Eurocrypt,ACNS,ACISP,….E.g.TWChimetal.,"OPQ:OT-basedPrivateQueryinginVANETs,"toappearintheIEEETITS,2011.TWChimetal.,"VSPN:VANET-basedSecureandPrivacy-preservingNavigation,“IEEETC,2012.TWChimetal.,“PAPB:Privacy-preservingAdvancePowerReservation”,IEEECommunicationsMagazine(CM)2012.PatrickChanetal.,“Hea