几类混沌加密系统的分析、改进及应用

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1、重庆大学博士学位论文几类混沌加密系统的分析、改进及应用姓名：陈勇申请学位级别：博士专业：计算机应用技术指导教师：廖晓峰20060401重庆大学博士学位论文(6)基于矩阵映射提出了一类新颖的图像加密系统该加密系统的密钥易于扩展具有强的抗差分攻击的优良特性(7)最后对论文工作进行了系统的全面总结并对今后的研究方向进行了展望关键词混沌信息安全密码学混沌密码密码分析矩阵映射II英文摘要ABSTRACTWiththerapiddevelopmentandextensiveapplicationsofcomputerandcommunicatio

2、ntechnologies,digitalinformationisbeingappliedmoreandmorewidelyintheworld.Digitalinformationiseasytocopyanddistribute,thisalsoproducesmanysecurityproblemsinitsapplications.Asaresult,thesecurityandprotectionofdigitalinformationarebecomingincreasinglyakeyproblemthatmustbe

3、solvedurgently.It’swellknownthatcryptographyisthefundamentalmethodforinformationsecurity.Thereisnaturalrelationshipbetweenchaosandcryptography:strongdynamicalpropertiesofchaoticsystemimplystrongcryptographicalproperties,andthebasicwaytodesignstrongcryptosystemimpliesqua

4、si-chaos.Since1980s,theideaofusingchaoticsystemstodesignnewciphershasattractedmoreandmoreattention.Recently,muchmorecontributionsaremadetogetmanypromisingachievements.Atthesametime,somesystematicwaystodesignchaoticciphershavebeenproposedwithcarefulconsiderationsonthesec

5、urityofalgorithms.Thisdissertationfocusesontheanalysisanddesignofchaoticcryptosystems.Themainachievementsandoriginalitycontainedinthisdissertationareasfollows:(1)Theresearchstatusandadvancesofchaoticciphershasbeensummarized,analyzedandreviewed.Theanalyzingmethodofchaoti

6、cblockcipherhasbeenexpatiatedindetail,andseveralexistentkeyproblemstobesolvedurgentlyhavebeenpointedout.(2)WesuccessfulattackthechaoticcryptosystembasedondiscretizedskewtentmapproposedbyMasudaetal.Achosenplaintextattackrequiringonlytwoplaintextsisproposed.Thetestresults

7、demonstratethatthisencryptioncryptosystemiseasilybrokenundertheproposedchosenplaintextattack.Animprovedcryptosystemisproposedwithkeyexpansion,whichismoresecureandscalablethanpreviousversion.(3)SecurityanalysisofanenhancedBaptista-typecryptosystemproposedbyS.Lietaliscarr

8、iedoutindetail.Weshowthatthiscryptosystemstillleakpartialinformationonthecurrentchaoticstateandreducethesecure