Hardware Implementation of hash functions

Chapter 12:Security for RFID Tags111CHAP 12:IntroductionRFID Automatic IdentificationRFID System ComponentsQuery Radio Frequency SignalApplicationsItem ManagementPhysical Access ControlTravel DocumentFinanceProduct Counterfeit Countermeasure and many more..

22RFID HISTORYFirst Application was US and Britain attached to identify planesExpensive till 1998MIT proposed low cost RFID Tags no battery, no transmitter ,simple circuitsBackscattering Communication

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RFID Tags commercial use Identifier Electronic Product Code(EPC)Auti ID Center 1999900 Mhz chosen as rangeSupported by Proctor and Gamble joined by Walmart 2001EPC Global Inc formed and joint venture between UCC AND EAN EPC global Inc Non Profit organisation 4RFID ApplicationsItem ManagementSupply ChainProduct to market suppliers manufactures ,shippers,storage facilities,distributors,retailersLogisticsManagement of Supply ChainInventory ControlOrdering ,maintaining ,correct amount of stockEquipment ManagementRepair and maintenance usage to particular jobUS mandated RFID tagging of expensive cases by 2005June 2003 Walmart requested top suppliers to use RFID taggingWalmart announced to put RFID tag on clothes to ensure good inventory5RFID Applications contd.

PHYSICAL CONTROLUnlocking and starting automobileToll RoadsDoor to BuildingPrepaid parking GarageElectronic PassportsE passports embedded RFID TagsCalled smart cardsCapable of performing cryptographic algorithmsDHS people Access Security Services PASS CardLow Cost,UHF RFIS,US CitizensUHF Range 20 feet but passport normal range 4 inches RFID to be used in Drivers License State Act 2005 RFID License

6MD5 and SHA 2 use Merkle Damgard model and logical functions for computation

Applications of HashData IntegrityAfter receiving data on can compute hash of the received data and compare with the hash of the received data which can be sent through secure channels ,second preimage resistanceDigital Signatures Hash functions can be used to generate public key algorithms .One can sign the document by encrypting hash of the message with private key .The ciphertext can be used as signature .Anyone who wants to verify can decrypt with public key and compare decrypted value with hash generated from message 7RFID Applications contdTracking LivestockVisibility of animalsTrack origin of diseaseRFID Tag in syringeTag in capsule special chemical in capsule bonds with skin does not removeIdentifier in database8

RFID Applications contdVeriChip human implantable RFID tag at 134 KHzSize of uncooked riceHealthcare applications medical device identification ,portable medical records including insurance,medical facility connectivity,Used in Hurricane 93.AuthenticationHash functions can be used for authentication as well .In this case hash value of the users password instead of password itself is transmitted and compared by the server .

When computing the hash password may be concatenated with random value generated by server .Hence hash are different every time 10RFID Reference ModelSix Layer Reference ModelApplication LayerItem Management AnticounterfeitingMiddleware LayerSoftware that translates or filter data from reader to standard applicationNetwork LayerCommunication pathway reader and serverEthernet Wifi IPReader LayerArchitecture of ReaderComputer and Transreceiver to one packageMedia Interface LayerWay Reader access control to media Wireless communication to coordinate each tag in tag groupTag LayerPower Harvesting circuit ,modulator ,demodulator ,memory layout

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TYPES OF RFID TAGSTHREE CATEGORIESPASSIVENo Battery, simple circuit, backscattering communication SEMIPASSIVEHave battery , passive style backscattering communicationIncreased sensitivity ,faster turn on timeToll RoadsUsing Backscattering communication extends battery lifeACTIVEHave battery and Transmitter Expensive Low battery life 12ATTACKS FOR IMPERSONATIONAdversary try to imitate the the target tag Four CategoriesTag CloningAdversary copy memory content and unique identier and clone the tag EPC Class 1 tag cant be prevented for cloningForms indistinguishable tags passive tags 2 tags with same identifier confuse readerTag SpoofingAlso called tag emulationSame as Tag cloningPhysical reproduction of custom design to imitate and emulate the authentic tagCan fool the automated checkout thinking product on shelfAdversary knows legitimate communication protocols and secrets

13Attacks for Impersonation contd.. Relay AttackPassive RFID communicate in close proximity If tag accessible then its assumed its in rangeVirtual clone through relay attackLeechGhost

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The two devices work in relay Communication via Leech and ghost sent over wired communication channelAuthentic Tag and Reader can be fooled that they are exchanging data with each other Data can be modified during communicationNot bounded by regulatory standardElectronic voting machine,e passportsReplay AttackAdversary may use captured reader tag communication at a later time Data protected by strong cryptography and authentication susceptible to attacks

15Attacks for Information LeakageAttacks focus on acquiring data stored in tag ,causing information leakageAttacks includeUnauthorised Tag ReadingCovert ChannelSide Channel AttackTag Modification

16Un-authorised tag readingSimplest attackIllegitimate reader is placed to access tag data within proximity of tagCost and power constraints data on passive tags not secureNo encryption algorithm Have no on\off switch17

2.Covert ChannelUnintended or authorised communication paths that can be used to transfer information that violated the security proceduresFor Passive RFID Tags its possible to create communication channels through user defined memory banks Secretly report medical or social information3.EavesdroppingAdversary uses electronic device with antenna to listen forward channel or backward channel communication Easy to capture the forward channel communication from greater distanceData captured can be used in relay or replay attack

184.Side Channel AttacksHaving crypto module on RFID Tag not enoughTarget Hardware implementation rather than the algorithmCMOS circuits have different power,delay,electromagnetic interference,which can be recorded by adversary Side Channel easily defeat AES,DES,RSA,ECC algorithmsWireless nature makes it easy to capture the above information5.Tag ModificationModify data stored on the tagAdversary may wipe out price stored on tagMedical information may be easily modifiedRFID tags have user writable memory exploited by adversary to modify and delete the previous informationEffectiveness on Tag organisation data and WRITE mechanism implemented on tag19Attacks for Denial of Service(DOS)

Adversary try to break communication link between tag and reader and disable reader from accessing the tag Attacks in this category areKill command abusePassive RFID implement KILL command abuseTag stop responding further queriesProcess protected by password on tagSet of tags share same KILL commands or master passwordsKill command may make tag unresponsivePassive InterferenceLink between RFID tag and reader is susceptible to interference of water or metalRadio waves bounce off surfaces cancelling effect in unintentional wayAdversary may use foiled line bags to shield tags from electromagnetic interference to block the accessJammingActive signals send out the radio signals to disrupt the reader tag communicationThis type of attack can be carried out using radio noise generators eg power switching supplies and electronic generators

20Attacks Through Physical ManipulationAttacks in this category requires adversary to be in physical contact with the tag and readerThe attacks in this category includePhysical TamperingObtain or modify the data stored on tagCan be done through microprobing,focussed ion beam editing,fault injection,and laser cutter microscopesCostly Able to bypass logical level security e.g. password and authenticationTag Swapping ,Removal, and DestructionSwapping is to swap tags between two objectsRemoval is removing tag from associated objectPhysically disable tags through the use of chemicalsAdvantage of poor tag adherence to the objectTag ReprogrammingTargets those tags that are programmable through RF or wired devicesAdversary either creates clone of the tag or cause inconsistency between the data and tag stored in the database21Fingerprinting RFID tags For AnticounterfeitingManufacturing Differences of RFID Tags can be used to fingerprint that is unique and to individual tag to prevent counterfeitingSteps involved are enrollment phase and verification phaseDuring an Enrollment phase features of the tag are measured to create the fingerprintDuring the Verification phase features of tag that claims to be authentic tag are measured and resulting fingerprint is compared with enrolled fingerprint using the matching algorithm22Fingerprinting RFID tags For Anticounterfeiting23Basic steps involved in fingerprintingRF fingerprint uniquely identifies amplitude ,phase, frequency caused by hardware changes which can be used by military to uniquely find the location of the transmitterChallenge of fingerprinting is that tag modifies signal sent from the reader HF RFID tags used in e passports were able to distinguish different models of tags but not the different tags of same modelFocus on measuring the transient response Passive HF RFID tag operate in near field and uses inductive couplingExpensive high bandwith oscilloscope is required to such signals

Tag Minimum Power ResponsePassive UHF RFID tags fingerprinting is done using MPR(Minimum Power Response)MPR-minimum power required for a tag to power up and respond at multiple frequenciesMeasured using bottom up algorithmRepeatedly send signals from reader to tag starting at low power level and increasing the power until the response is detected50 same model tags are taken measured 6 times at 101 different frequencies between 860MHz and 960MhzAfter measuring data is analysed through statistical two way analysis ANOVA to determine if tags had different MPRs Result were Different tags have a significant effect on MPR and frequency has a significant effect on MPRAfter determining the MPR of different tags author used MPR as fingerprint in the identification systemThe K nearest algorithm was used to identify the given tag based on previous enrolled tagThe identification system effectiveness was measured using the False Positive Rate(FP),AND Area under Receiver Operating Characterstic Curve(ROC AUC)

24Tag Minimum Power ResponseA True Positive value is an instance where the measurement of tag is positively associated with the correct tagA False Positive value is an instance where the measurement of tag is positively associated with the incorrect tagAn ROC plot is fraction of True Positives against the fraction of false positivesThe are under the ROC curve represents the probability of randomly chosen positive matching instance being ranked higher than the chosen incorrect instanceA table is shown to show the results

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Tag Frequency and Transient ResponseInvestigated in passive UHF RFID tagsResults showed difference between different tag models in third and fifth harmonics but not significant difference between same tag models tagsTag Transient response is used to create the fingerprint in transmitters like cell phonesThe tag transient response is part of signal from the tag when it tries to backscatter the information to the reader.Fingerprint did not work for passive UHF tags because these tags do not have active power source and they work in far field 26Tag Timing ResponseThree different model tags were tested by measuring ten tags of each modelThe time used to send the ID , checksum,and control bits when queried by reader was measured and it was found to be unique for two of the three models of tags that were tested After determining that the tag response is different it was used to fingerprint the tagIdentification system for each model was used to measure the worst case analysisKNN was used as the matching algorithm to identify a given tag based on previously enrolled TR and following data was obtained27