1. RFID Security and Privacy: A Research Survey
Written by: Ari Juels
Presented by Carlos A. Lopez

2. Outline
Introduction
Basic RFID Tags
Symetric-Key Tags
RFID News

3. 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
Has come to attention because
Walmart
Procter and Gamble
Department of defense
Are making and effort to deploy this tech as a tool for automated oversight of their supply chain.
- Low costs and Standardization will create an explosion in RFID use

4. RFID Overview Tags (transponders) Reader (transceiver) Database
Credit Card #
Radio signal (contactless)
Range: from 3-5 inches to 3 yards
Tags (transponders)
Attached to objects,
“call out” identifying data
on a special radio frequency
Reader (transceiver)
Reads data off the tags
without direct contact
Database
Matches tag IDs to
physical objects

5. Reading Tags
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

6. Barcode Replacement Unique Identification Automation
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
Advocates of RFID see as a successor of bar codes
EPC – Electronic Product Code tag – Main form of Barcode type RFID
EPCGlobal is a Joint Venture of UCC and EAN the bodies that regulate barcode use in world
EPC tags cost around 13cent in large quantities but their cost will drop dramatically in the next few years
The code cant be up to 96bits.
They develop a public object lookup database called ONS (Object name service) an acts as a DNS and the purpose is to route tag queries to the database of tags owners and managers

7. 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 9303.
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.
Currently the big distributors and governmental customers are pushing EPC heavily as a standard well accepted in their community, but not yet regarded as for salvation to the rest of the world.

8. Tag Types Passive: Semi-passive Active:
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
Passive tags There are 4 different ranges to consider:
Nominal range: Read range at which the tag is consider to operate.
Rogue scanning range: Sensitive reader with a very powerful antenna can exceeded the nominal range
Tag-to-Reader Eavesdropping range: Once a reader has powered a tag, a second reader can monitor resulting tag emissions without itself outputting a signal.
Reader-to-tag eavesdropping range: in some cases a reader transmits information to a tag. Because reader transmit at much higher power they are subject to eavesdropping. LF HF
UHF
Microwave
Freq. Range
KHz
13.56 MHz
MHz
GHz
Read Range
10 cm 1M
2-7 M
Application
Smart Cards, Ticketing, animal tagging,
Access Control
Small item management, supply chain,
Anti-theft, library, transportation
Transportation vehicle ID, Access/Security, large item management, supply chain
Transportation vehicle ID (tolls), Access/Security, large item management, supply chain

9. Applications Supply-chain management Payment systems Access Control
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

10. The consumer privacy problem
1500 Euros
in wallet
Serial numbers:
597387,389473…
Wig
model #4456 (cheap polyester)
30 items
of lingerie
Das Kapital and Communist-party handbook
Replacement hip
medical part #459382
Here’s
Mr. BOB
in 2015…
Privacy and tracking problem

11. …the tracking problem Wig serial #A817TS8
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
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.
Tracking Tracking: Serial number is combined with personal information such as the credit card
EPC tags carries the Unique Serial Number, The manufacturer object and the product code (SKU Stock Keeping Unit)
What types of medication therefore what illnesses he may suffer?
Loyalty cards therefore where he shops?

12. CURRENT BALANCE WMATA Smart Trip RFID
Travel history: visited stations and dates
Tracking example…
WMATA Smart Trip RFID

13. …and the authentication problem
Wig serial #A817TS8
Privacy: Misbehaving readers harvesting information from well-behaving tags
Authentication: Well-behaving readers harvesting information from misbehaving tags, particularly counterfeit ones
The food and drugs administration FDA, has called the pharmaceutical industry to apply RFID to pallets and cases by 2007, with the aim of combating counterfeit pharmaceuticals.
Texas Instruments and Verisign has proposed a digital signing of data to provide integrity.
If a reader detects 2 or more tags with the same serial number it is clear that a problem has arisen

14. 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
This caterorization is rought, because they can uses other features such as
Memory
Communication Speed
Random-number generation
Power
However it serves their purpose of in demarcating available security tools.

15. Privacy Killing and Sleeping Re-naming approach The proxy approach
Relabeling
Minimalist cryptography
Encryption
The proxy approach
Watchdog Tag
RFID Guardian
Distance Measurement
Blocking
Soft-blocking
Trusted Computing
The lack of cryptography in basic RFID is a big impediment to security design
Privacy has focused on the consumer privacy.

16. 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

17. 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
The tags carries a unique identifier S
PK Public Key and law-enforcement have the Secret Key SK
Shops and banks possess re-encryption readers program with PK
S encrypted with the Key emits C an only decrypted by SK

18. Privacy (Cont 3) The proxy approach Watchdog Tag RFID Guardian
Privacy has focused on the consumer privacy.

19. 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
The guardian might implement a policy like “My tags should only be subject to scanning with 30meter of my home”

20. 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 has focused on the consumer privacy.

21. Privacy (Cont 5) Blocking Trusted Computing
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
Privacy has focused on the consumer privacy.

22. 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.

23. 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
The tag transmit Ti
The reader generates a random bit string R
The tag computes H=h(Ki,R) and transmits H
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

24. 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 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)

25. Privacy Literature Tree approach Synchronization 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

26. So what might solve our problems?
Cryptography!
Urgent need for cheaper hardware for primitives and better side-channel 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?

27. RFDI News
RFID Passports cracked -
Can Aluminum Shield RFID Chips? -
RFID chips can carry viruses -
Nightclub allows entry by RFID’ -
Demo: Cloning a Verichip -