Computer Security and Cryptography Partha Dasgupta, Arizona State University

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  • Computer Security and Cryptography

    Partha Dasgupta, Arizona State University

  • The ProblemIf I didn't wake up, I'd still be sleeping.

  • Not just hype + paranoiaInternet hosts are under constant attackFinancial losses are mountingMiscreants are getting smarter (and so are consumers)National Security risks were stated and then underplayedData loss threatens normal users, corporations, financial institutions, government and more


    HOW? WHY? and What can we do?

  • OverviewPart 1: Security BasicsPart 2: AttacksPart 3: CountermeasuresPart 4: CryptographyPart 5: Network SecurityPart 6: System SecurityPart 7: State of the Art and Future

  • Part 1: Security BasicsComputer and Network Security basicsHackingAttacks and RisksCountermeasuresSecrets and AuthenticationParanoia

  • Computer and Network SecurityKeep computers safe from program execution that is not authorizedKeep data storage free from corruptionKeep data storage free from leaksKeep data transmissions on the network private and un-tampered withEnsure the authenticity of the transactions (or executions)Ensure that the identification of the human, computer, resources are establishedWith a high degree of confidenceDo not get stolen, misused or misrepresented

  • Hacking or CrackingPlain old crimePhone PhreakingCredit cards, the old fashioned wayTechnology HacksDesign deficiencies and other vulnerabiliteATM, Coke Machines, Credit Cards, Social EngineeringSoftware hacksSecond channel attacksRFID issuesCell phone vulnerabilitiesGrocery cards?

  • Attacks and RisksAttacksAn attack is a method that compromises one or more of: - privacy (or confidentiality) - data integrity - execution integrityAttacks can originate in many waysSystem based attacksNetwork based attacksUnintended ConsequencesRisk a successful attack leads to compromiseData can be stolen, changed or spoofedComputer can be used for unauthorized purposesIdentity can be stolenRISK can be financial

  • Attack TypesSystem based attacksVirus, Trojan, rootkitAdware, spyware, sniffers A program has potentially infinite powerCan execute, spawn, update, communicateCan mimic a human beingCan invade the operating systemNetwork based attacksEavesdroppingPacket modifications, packet replayDenial of ServiceNetwork attacks can lead to data loss and system attacks

  • CountermeasuresSystem Integrity ChecksVirus detectorsIntrusion detection systemsSoftware signaturesNetwork Integrity checksEncryptionSignatures and digital certificatesFirewallsPacket integrity, hashes and other cryptographic protocolsBottom Line:We have an arsenal for much of the network attacksSystem security is still not well solved

  • What is at Risk?Financial InfrastructureCommunication InfrastructureCorporate InfrastructureConfidentiality and Privacy at many levelsEconomyPersonal Safety

  • The Shared Secret FiascoOur authentication systems (personal, financial, computing, communications) are all based on shared secretsID numbers, Account numbers, passwords, SS#, DOB When secrets are shared, they are not secretsThey will leak!Given the ability of computers to disseminate information, all shared secret schemes are at extreme riskMedia reports of stolen data is rampant

    The Fake ATM attackThe check attackThe extortion attack

  • How do secrets leak?Malicious reasonsSimple mistakesOversightBad human trust managementBad computer trust managementNothing can go wrongPlease believe in Murphy!

  • Keeping Secrets?Simple answer, not possible.Encryption is good, but data has to be unencrypted somewhereDisappearing Ink?Use paper based documents, not scanned.

    Public Key Encryption has much promise (PKI systems)Shared secrets need to be eliminated as much as possibleSeparate out of band communicationsPhone, postal mail, person-to-person

  • AuthenticationShared secrets are used for authenticationUsername/passwordsMulti-factor authenticationWhat you knowWhat you haveWhat you are, what you can do.Most of the authentication methods are quite brokenDesigned when networking was not aroundPKI systems are better, but not deployedToo many false solutions (dangerous, gives a feeling of security)

  • PasswordsThe password is known to the host and the clientUnder some password schemes the host does not know the password (e.g. Unix)Passwords can leak from host or from clientSame password is used for multiple sitesPassword managers are not too effectiveGood passwords are not as good as you thinkInvented for a completely different purpose, using passwords on the web, even with SSL encryption, is a bad idea

  • False SolutionsBiometricsA digital bit string, or password that cannot be changedPlenty of attacks possible, including framing

    RFID identificationPlenty of attacks possible

    Multi-Factor authenticationBetter, but still not good

    Smart cards (the not-so-smart ones)Again, based on shared secrets, have attacks and limitations

  • Paranoia?A large number of computers (consumer, business) are compromised or used for fraudViral infections, zombiesMany web servers are for fraudulent reasonsSpam is an indicatorUnprecedented lying, cheatingAdware, popups, spywareAll attempting to mislead, steer, and victimizeIdentity theft, financial theft, cheatingProbably at an all time high

    Security Awareness is often coupled with paranoiaIt is necessary to be paranoid!

  • What is the point of an attack?

    Get your shared secrets for financial gain

    EspionageDisruptionPersonal Corporate Financial System Identification

  • Computer SecuritySoftware needs to be verifiably untampered and trustedNetworks need to be free from tampering/sniffingData has to be secure from stealing and tamperingEnd user protection

    A coalescing of software, hardware and cryptography along with human intervention and multi-band communication.