PowerPoint Presentation

Security and Trust Issues in 3D ICsJennifer DworakSouthern Methodist University

Al CrouchASSET InterTech

Presented at the 2011 Board Test Workshop, October 25-27, 2011Overview: Security needs to be considered in design and test of 3D ICsSecurity is a already significant concern for 2D Trojans and CounterfeitsMeasures exist to expose both

Security and Trust is much more complex in 3DLack of access to each dieComplexity of developing functional testsIndividual die are hidden between other dieVertical routes are more difficult to virtually probe for illicit connections

Types of Counterfeits in 2DReverse engineer, design, and manufacture chips to be functionally similar to the originalSalvage old chips from boards and sell them as new chipsRe-label low-performing die as high-performingSell defective parts as working chips

Impact of counterfeitsLess reliable than valid dieHarms the reputation of the real chip providerDenies revenue to original chip providerIncreases support costs the counterfeit die may require support or may be returnedMay contain malicious functionality

Selected Counterfeit IncidentsBetween 2007 and 2010 over 5.6 million counterfeit semiconductor devices were seized by Customs and Border Patrol (CBP) and ICE (Immigrations and Custom Enforcement)In 2009, a NASA probe project was delayed nine months and went 20% over-budget due partly to counterfeit parts.Entire NEC product line was counterfeited in across multiple factories in China and TaiwanCompany called VisionTech imported more than 3200 identified or suspected shipments of counterfeit microelectronics to the U.S.Sold to military for use in missile targeting systems, identification friend-or-foe systems, among othersThousands of parts may still be in the supply chain

VisionTechs Cost to CompaniesAMD$34.9KNational Semiconductor$5.9KAltera$7.6KNEC$24.8KAnalog Devices$75.6KPeregrine Semiconductor$2.6KCypress Semiconductor$33.4KPhillips Electronics$1.6KFreescale$40KRenesas$2.4KInfineon Technologies$10KSamsung Elect. America$77.2KIntel$100.9KSTMicroelectronics$18.6KIntersil$1.9KTexas Instruments$92.9KLinear Technology$32KToshiba$2.4KMaxim$1.6KXilinx$22.2KMitel$2.6KTotal$591.4K6Detecting/Avoiding CounterfeitsBuying from authorized suppliersInspection of packagingIncoming testDevice authentication (e.g. with die ID and a trusted database.)Reporting suspected or discovered counterfeit incidents to an anti-counterfeiting clearinghouseHardware TrojansMalicious changes to a design intentionally inserted by an attackerMay be inserted at any stage of the design and manufacturing process: specification, RTL, manufacturing, supply chainMost attention has focused on manufacturingInserted with the intention of being stealthyTwo components:TriggerPayload

2D Circuit with Combinational TrojanTrigger should be stealthyB=0, C=0 should be rare during functional operationB=0, C=0 should not be targeted during structural test.

TriggerPayloadPayload should affect something of functional importance to attackerLeak DataCause ErrorsReduce PerformanceDestroy the chipSequential 2D TrojanTriggerCounter01Encryption circuitciphertextkeyData to broadcastplaintextHow can we detect Trojans inserted at manufacturing?Logic testing is generally ineffectiveToo hard to activateSide channels affected by even inactive TrojansDelayPowerObtain fingerprints of chips verified as Trojan-freeProcess variations make comparison difficult Difference between Trojan and non-Trojan containing circuits is very small.Only works if Trojan is inserted at maskChip IDDelayFingerprintgoodbadReal Life Trojans.

On September 6, 2007, the Israeli Air Force carried out an airstrike on a Syrian nuclear reactor in Operation Orchard.

Hidden back door in microprocessors used in radar may have allowed them to be disabled remotely.

beforeafterFrench microprocessors used in military applications have remote kill switches to allow them to be disabled.During the Cold War, secret cameras were inserted inside Xerox 914 copy machines in the Soviet embassy to record copied documents.So what changes in 3D?Where can Trojans and Counterfeits be inserted?

ManufacturingSpec

Supply ChainDesign

3rd Party AssemblerDie Access and ObservabilitySo what does this mean for security?Die in 3D ICs are less observable.An entire board in a packageAccess to all die comes only through the base dieCant visually inspect die once assembledCant remove and analyze die once assembled.Overall variability is likely to increase.

Its easier to hide things and harder to find them!!

Potential 3D Security IssuesBase DieInterposerUpper Die2D Trojan in Real DieTrojan in InterposerCounterfeit Die or InterposerTrojan Firmware in Programmable DieTrojan Extra DieIssue 1: 2D Trojan in a DiePotential Actions:Data Collection and Transmission (e.g. encryption codes)Denial of Service or Early Reliability Failures (such as generating a high temp spot)Chip/Die Destruction (e.g. on-demand kill-switch)

Base DieInterposerUpper DieTrojan in Real DieDetecting a 2D Trojan in a 3D StackVariations increase in 3DRelative size of Trojan effect is minisculeMay need to shut off power to all but one dieNeed ability to obtain accurate delay measurements to flops and TSVsVerify design and 3rd party IP at RTL

Base DieInterposerUpper DieTrojan in Real DieIssue 2: Counterfeit Die or InterposerSame as 2D:Less reliable and may contain TrojansBuy from trusted sources & perform incoming testAuthenticate on-die device ID with a trusted databaseNew ProblemsPoor copying of packages no longer helps with detectionNeed to access device ID securely through stackCan no longer replace by desoldering from board.

Issue 3: Extra Die in StackOriginal Die StackExtra Die in stack can cause complex Trojans

If TSV information is standardized or published, that info can be used by Trojan designer to access desired info.

RF Antenna could be added with an extra die on top of the stack and broadcast the data on the busRF TX dieExtra memoryand controller dieOut of band TSVsExtra memory and controller die can save selected data for later extraction.Detecting Extra Die in StackDepends on where in the stack extra die are located: top of stack is harder:Strategies:Voltage dropTemperature ProfileSide Channel Analysis (Power and Delay)X-rays or other imaging approaches

Extra processorExtra processor die can drive data bus with opposite values when triggeredshorting power and ground.Issue 4: Evil FPGAs in StackFPGAs likely to be included for valid reasons:Replace ASICsBuilt-in Self RepairTest other parts of stackSecurity Concerns:Firmware CorruptionExtra FPGA in stackTrojan can be inserted in the field

Hot Spot on FPGA die created by significant switching when Trojan die is triggered.

Very complex Trojans are possibleIssue 5: Trojan InterposersUpper DieLower DieInterposerSilicon Interposers may be needed to align TSVs on adjacent dieincluding TSVs for power and ground.Upper DieLower DieTrojan InterposerTrojan LogicTrojan Logic in the Interposer (or in one of the die in the stack) could be used to shut off power or data to all upper dieIn 2D, this is like shutting off power or data to most of the chips on the board!!!If the Trojan is in an interposer, it would not be visible to JTAG or any other DFT hardware by design.Issue 6: Incorrect Die OrderingProcessorMemoryASIC 1ASIC 2RF TransceiverOriginal orderingProcessorMemoryASIC 1ASIC 2RF TransceiverTrojan orderingEspecially if standard interposers are available, an attacker could reorder the die.Causes loss of reliability and performance.Detection Methods: Testing and Die IDs (JTAG, INTEST, etc.)Issue 7: Protecting IPToday, defective chips can be de-soldered and sent back to the manufacturer for FA.In 3D entire stack will need to be spent.

Need to be able to access individual die for debug.Need to protect the IP of each die provider.

AMD ProcessorTI Analog DieMemoryARM Core

OutlookSome of these issues are likely easier to solve than others.Even the easy ones wont be detected if you arent looking!When 3D assembly issues are solved and 3D becomes commonplace, really evil counterfeits are possible.Easy to manufacture with standard, interchangeable dieHard to detect in packageIncoming Test is Mandatory!

Conclusions3D Security and Trust must be addressed at both design and test.Research is needed to mitigate these issues now.Waiting may make solutions much more expensive or impossible to implementIf we dont look for these issues, they will happen, and the consequences could be disastrous.

The End.