RFID Overview. Outline. Definition. Barcode Replacement. Reading Tags

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1 Outline 1. Introduction 2. Basic RFID Tags 3. Symetric-Key Tags 4. RFID News Written by: Ari Juels Presented by Carlos A. Lopez Definition RFID: Is a technology for automated identification of objetcs and people RFID devices are called RFID Tags Small Microchip (Itachi Mu-chip 0.002x0.002in) Transmit data over the air Responds to interrogation Possible successor of barcodes EPCGlobal Inc Oversees the development of standards RFID Overview ID: Tags (transponders) Attached to objects, call out identifying data on a special radio frequency Credit Card # Radio signal (contactless) Range: from 3-5 inches to 3 yards Reader (transceiver) Reads data off the tags without direct contact Database Matches tag IDs to physical objects Reading Tags Barcode Replacement The read process starts when an RFID reader sends out a query message Invites all tags within range to respond More than one RFID tag may respond at the same time This causes a collision Reader cannot accurately read information from more than one tag at a time Reader must engage in a special singulation protocol to talk to each tag separately Unique Identification Type of Object Vs. Unique among millions Act as a pointer to a database Automation Optically scanned Line-of-sight Contact with readers Careful physical position Requires human intervention

2 RFID Standards Some standards that have been made regarding RFID technology include: ISO 14223/1 RFID of Animals, advanced transponders ISO 14443: HF (13.56 MHz) RFID-enabled passports under ICAO ISO 15693: HF (13.56 MHz) used for non-contact smart payment and credit cards ISO/IEC different Parts ISO 18185: "e-seals" for tracking cargo containers using the 433 MHz and 2.4 GHz frequencies. EPCglobal - Most likely to undergo International Standardization according to ISO rules as with all sound standards in the world. Tag Types Passive: All power comes from a reader s signal Tags are inactive unless a reader activates them Cheaper and smaller, but shorter range Semi-passive On-board battery, but cannot initiate communication Can serve as sensors, collect information from environment: for example, smart dust for military applications Active: On-board battery power Can record sensor readings or perform calculations in the absence of a reader Longer read range LF HF UHF Microwave Freq. Range KHz MHz MHz GHz Read Range 10 cm 1M 2-7 M 1M Application Smart Cards, Ticketing, Small item management, Transportation vehicle Transportation vehicle ID animal tagging, supply chain, ID, Access/Security, (tolls), Access/Security, Access Control Anti-theft, library, large item management, large item management, transportation supply chain supply chain Applications The consumer privacy problem Supply-chain management logistics, inventory control, retail check-out Payment systems ExxonMobil SpeedPass I-Pass/EZ-Pas/Smart Tag toll systems Credit Cards Access Control Passports Library books Hospital and Health Centers Money - Yen and Euro banknoter anti-counterfeiting Animal Tracking - and Human??? Human-implantable RFID Here s Mr. BOB in items of lingerie Replacement hip medical part # model #4456 (cheap polyester) Das Kapital and Communistparty handbook 1500 Euros in wallet Serial numbers: , the tracking problem Mr. Bob pays with a credit card - his RFID tags now linked to his identity determines level of customer service Mr. Bob attends a political rally - law enforcement scans his RFID tags Mr. Jones wins Award - physically tracked by paparazzi via RFID serial #A817TS8 CURRENT BALANCE Read ranges of a tag Nominal Range Range intend to operate Rogue Scanning Range Powerful antenna amplifies the read range Tag-To-Reader Eavesdropping range A second reader can monitor the resulting tag emission Reader-to-Tag eavesdropping range - Sometimes the reder send information with a greater power than the tags. Travel history: visited stations and dates WMATA Smart Trip RFID

3 and the authentication problem Privacy: Misbehaving readers harvesting information from wellbehaving tags Authentication: Well-behaving readers harvesting information from misbehaving tags, particularly counterfeit ones serial #A817TS8 Basic RFID tags Vs. Symmetric Key tags Cannot: Execute standards cryptographic operations Strong Pseudorandom number generation Hashing Low-cost tags EPC tags Used in most gates Privacy Killing and Sleeping Re-naming approach Relabeling Minimalist cryptography Encryption The proxy approach Watchdog Tag RFID Guardian Distance Measurement Blocking Soft-blocking Trusted Computing Returning to basic issue of privacy: Kill codes EPC tags have a kill function On receiving password, tag self-destructs Tag is permanently inoperative No post-purchase benefits Developed for EPC to protect consumers after point of sale Dead tags tell no tales Privacy is preserve Why not sleep them? Would be difficult to manage in practice Users might have to manage her PIN for her tags Privacy (Cont 2) Re-naming approach Even if the tag has no intrinsic meaning it can still enable tracking (Solution: Change over time) Relabeling Consumer are equipped to re-label tags with new identifier, but able to reactive old information Minimalist cryptography Change names each time is interrogated Encryption Re-Encryption - Public Key cryptosystem - Periodically re-encrypted by law enforcement Universal Re-encryption Privacy (Cont 3) The proxy approach Watchdog Tag RFID Guardian

4 So what might solve our problems? Higher-powered intermediaries like mobile phones RFID Guardian and RFID REP (RFID Enhancer Proxy) Please show reader certificate and privileges Privacy (Cont 4) Distance Measurement Distance as a measure of trust A tag might release general information I m attached to a bottle of water when scanned at a distance, but release more specific information, like unique identifier at a close range. Privacy (Cont 5) Blocking Scheme depends on the incorporation of a modifiable bit called a privacy bit It uses a blocking tag which prevents unwanted scanning of tag on a private zone Soft-blocking -On the reader Do not scan tags whose privacy is on Trusted Computing Authentication ECP tags Class-1 Gen-2 have no explicit anti-counterfeiting features Yoking: Is a protocol that provides cryptographic proof that 2 tags have been scanned simultaneously to try to solve that the reader actually reads what is trying to scan. Symmetric-Key Tags (capable of computing symmetric key) Cloning With a simple challenge-response protocol a tag T, can authenticate itself to a reader that shares the key Ki 1. The tag transmit Ti 2. The reader generates a random bit string R 3. The tag computes H=h(Ki,R) and transmits H 4. The reader verifies H =h(ki,r) Digital Signature Transponders ( created by Texas Instrument and used by Speedpass) Based on the secrecy of the algorithm Security through obscurity was crack by student at Johns Hopkins Reverse-Engineering Key cracking Simulation Reverse - Engineering and side channels Relay Attacks Man-in-the-middle attacks can bypass any cryptographic protocol Privacy Symmetric-Key Management Problem Leads to a paradox A tag identifies itself before authenticating the readers The tag emits it identifier Ti So the reader can learn the identity of the tag Privacy unachievable Tag emits E = f kti [P] where P is a input value Once receiving E, the reader searches all the spaces of tags keys, trying to decrypt E under every key K until its obtains P (The reader has all the tag s key on it)

5 Privacy Literature Tree approach Proposed approach where a tag contains more than one symmetric key in a hierarchical structure define by a tree S. Every node has a unique key Each tag is assigned to a unique leaf It contains the key defined by the path from the root S to the leaf Can be useful for: A tag holder can transfer ownership of an RFID tag to another party, while history remains private A centralized authority with full tag information can provision readers to scan particular tags over limited windows time Synchronization approach Symmetric-key primitive The European network for excellence in cryptographic is evaluating 21 candidates stream ciphers So what might solve our problems? Cryptography! Urgent need for cheaper hardware for primitives and better sidechannel defenses Some of talk really in outer limits, but basic caveats are important: Pressure to build a smaller, cheaper tags without cryptography RFID tags are close and personal, giving privacy a special dimension RFID tags change ownership frequently Key management will be a major problem Think for a moment after this talk about distribution of kill passwords Are you ready for the Verichip? RFDI News RFID Passports cracked - atch_fi.html Can Aluminum Shield RFID Chips? - RFID chips can carry viruses - Nightclub allows entry by RFID bajabeachclub.htm Demo: Cloning a Verichip -