Overview of the latest RFID Research at Auto-ID Lab, ADELAIDE

1. Overview of the latest RFID Researchat Auto-ID Lab, ADELAIDE Alfio Grasso Deputy Director, Auto-ID Lab, Adelaide Overview of the latest RFID Research 21st March 2007

2. Overview • Auto-ID Lab, Adelaide • Security • Anti-Counterfeiting and Security • Authentication • Lightweight Cryptography • Specialised RFID Tag Antenna Design • Conclusions

3. Adelaide, Auto-ID Lab Overview of the latest RFID Research 21st March 2007

4. The Auto-ID Laboratories

5. Auto-ID Labs • One of 7 Auto-ID Labs around the world • MIT, USA • Cambridge, UK • Adelaide, Australia • Keio, Japan • Fudan, China • St Gallen, Switzerland • ICU, Korea

6. Three entities • Auto-ID Lab • EPCglobal research • via sub-award from MIT • RFID Automation • Contract Research • Eight Consultancies • One Research Contract • One Research Project • Australasian Adoption Research Initiative • RFID adoption, Networking, Resources

7. Contract Research • Separate from the EPCglobal funded work • Commercial Infrastructure • Adelaide Research & Innovation Pty Ltd • Intellectual Property Protection • Pork CRC Research Contract • Joint Strike Fighter

8. Auto-ID Lab, Personnel • Prof. Peter Cole • Mr. Alfio Grasso • Dr. Behnam Jamali • Mr. Damith Ranasinghe • Mr. Kin Seong Leong • Ms. Mun Leng Ng • Mr. Raja Ghosal • Mr. Manfred Jantscher (visiting)

9. Anti-counterfeiting and SecurityAuthenticationLightweight Cryptography Overview of the latest RFID Research 21st March 2007

10. Auto-ID Labs • In 2006 Global Auto-ID Labs launched the Flagship Project • Anti-Counterfeiting and Secure Supply-Chain • Focuses on protection against counterfeiting and on product traceability. • The main emphasis is on EPC technology without neglecting other methods. • In addition to the technology, topics include the impacts on processes within an enterprise, the assessment of customer acceptance and the analysis of business cases in order to examine operational efficiency. • http://www.autoidlabs.org/publications/page.html

11. Powering channel Authorised Legitimate Physical channel Interrogator Forward channel (Reader to Tag commands) Tag Backward channel (Tag to Reader responses) Insecure communication channel RFID Channels

12. Security and Privacy Concepts • Security aims • Confidentiality • Integrity • Authentication • Non-reputation • Availability • Privacy aims • Anonymity • Unlinkability

13. Security Models • Unconditional security • Perfect security, assumes unrestricted computational power of an adversary • Computational security • No known algorithm to break it within polynomial time • Practical security • No breaking algorithm within N operations, with N chosen to be high. Modern primitives offer practical security. • Provable security • Possible to show the complexity of breaking a primitive is equivalent to solving a well know supposedly hard mathematical problem

14. Security Services • Confidentiality • Only authorised parties receive information • Authentication • The ability of a party to be sure the message is from a claimed source • Integrity • Assures us a message is not altered on the way • Non-reputation • Proof of transmission and reception • Access Control • Restricts and controls access to a system • Availability • Provides means to assure a system is available when needed

15. Attacks • Ciphertext-only attack • Known-plaintext attack • Chosen-plaintext attack • Adaptive chosen-plaintext attack • Chosen-ciphertext attack • Adaptive chosen-ciphertext attack • Known-key attack • Man-in-the-middle attack • Replay attack • Impersonation attack • Dictionary attack • Incomplete session attack

16. Some Security Issues • Eavesdropping • Corporate espionage. • Victim of theft • Cloning and Physical attacks • Fraud: counterfeiting RFID-labeled items. • Theft: replace merchandise with decoy label. • Denial of service. • Corrupt data with fake tags. • Disrupt RFID-dependent infrastructures. • Communication layer weaknesses • Insecurities from tag generated random numbers • Power analysis of the powering channel

17. Some Privacy Issues • Profiling • Identify a person’s interest by the RFID items they carry • Tracking • Any RFID item can potentially identify the person • If a payment is made via a credit card, any tags on that person can be used to identify that person, and track them • Once the identity is known they can be tracked. • RFID enabled currency can be used to determine cash on a target.

18. RFID Security Framework • Low cost labels. • 200-4000 gates available for security (cost limitation). • Time available for operations : 5 -10 ms. • Label reading speeds: 1000-1500 labels/s. • Data transmission rates: in the order of 100kbps. • Labels reveal their presence through a non-identifying signal. • The long term security of label contents can not be guaranteed. • Power utilization of security related silicon should not exceed the tag power consumption range of 50-100 microwatts.

19. Initial Proposals • Kill tags at checkout. • Customers may want to build applications. • Erase unique identifiers at checkout. • Still allows tracking by tag “constellations”. • Restrict and detect unauthorized reads. • Cheap to build, hard to always detect. • Some scope is found with security schemes designed with reader distance based trust • Use strong cryptography to protect tags. • Too expensive for low-cost (5-cent) tags.

20. Cryptography Overview of the latest RFID Research 21st March 2007

21. Kerchoff’s principle • Do not rely on keeping an algorithm secret. • Even if you think no one will think of it, someone almost certainly will. • Publish an algorithm but keep the key secret. • That key should be chosen from amongst a large number of possible keys, that could be used. • Have some mathematical foundation for the belief that it will be hard to extract the key from what can be overheard.

22. Shannon insights • Add confusion and diffusion • Confusion: encoding the information, e.g. • Swapped (A -> X), shifted (A +3 =D), or Ac (mod p), • Diffusion: spreading the information, adding redundant information, or noise

23. Public Key Cryptography • Public key ciphers • Examples • RSA • Diffie-Hellman • ECC • Digital signatures • These form the second group of keyed cryptographic tools. Based on key pairs instead a single shared key. Only one key need be kept secret. Sometimes called asymmetric key systems. The receiving party issues the public encrypting key and keeps to itself the decrypting key.

24. Public Key Encryption The key pair used in the example is the secret key SBob of Bob and the public key PBob of Bob.

25. Precautions needed • In practice P is prime of 300 digits and a and b are at least 100 digits long • Is vulnerable to man in the middle attack • Cure is to digitally sign what is sent if a public key infrastructure is available, or use a pre-shared password.

26. Elliptic Curve Cryptography • Uses the discrete log problem • but over a finite abelian group of points x, y on an elliptic curve • y2 = x3 + a*x + b mod (p) • ECC keys can be shorter for the same security when compared with other systems • No mathematical proof of the difficulty has been published but the scheme is accepted as a standard by USA National Security Agency. • Keys must be large enough. • A 109 bit key has been broken (roughly same security to RSA 640) • 160 bits ECC - same security as RSA 1024 bits. • 224 bits ECC - same security as RSA 2048 bits.

27. One Time Codes Overview of the latest RFID Research 21st March 2007

28. Need for something simpler • RFID tags cannot support the computing burdens of the usual systems that are supported by significant computing power at both ends of a communication link, nor even of the lightweight protocols listed above. • There is a need for something significantly simpler • One Time Codes • Only proven security method by Shannon Entropy (1949) • Provides Perfect Secrecy

29. One time codes: 1 • Have available a set of purely random numbers in the tag and matching tag dependent number in a secure data based • Some are to authenticate the tag to a reader, some to authenticate a reader to a tag, some might be to permit authenticated change of tag identity to prevent trace of items • Use certain of these to XOR with tag identities to disguise them from eavesdroppers.

30. One time codes: 2 • Need a large supply to cater for many authentications • Options • Reserve a pair for final authentication by end user • Recharge in a secure environment • Assume an eavesdropper cannot be every where and use old codes for identity change for fresh reader or tag authentications • Better to use a shrinking function

31. Shrinking Generators Overview of the latest RFID Research 21st March 2007

32. The Shrinking Function • Two linear shift registers, A (data) and S (sampling), with different seeds, clocked together. • Outputs are combined as follows • If S is 1, output is A • If S is 0, there is no output and another clock is applied • This scheme has been resistant to cryptanalysis for 12 years. • No known attacks if • feedback polynomials are secret and • registers are too long for an exhaustive search.

33. R1 LFSR Clock Q D Buffer Output (K) CLK CE R2 LFSR Shrinking Generator • Shrinking Generator • Minimal hardware complexity • Shrink the output from LFSR R1 • Produce irregular sequence K • Practical alternative to a one time pads • Known attacks have exp time complexity • Keep connection polynomials secret • Use maximum length LFSRs

34. Physically Uncloneable Functions in RFID Overview of the latest RFID Research 21st March 2007

35. = y e ( x ) K Simple challenge-response protocol • Reader chooses a challenge, x, which is a random number and transmits it to the label. • The label computes and transmits the value y to the reader (here e is the encryption rule that is publicly known and K is a secret key known only to the reader and the particular label). • The reader then computes . • Then the reader verifies that.

36. A lightweight primitive • Physically Uncloneable Functions • Easy to compute but hard to predict • Alternative to storing keys on insecure hardware devices k ={ gate and wire delay variations due to IC fabrication process variations} f(c1,c2,c3,…,cm, k) {c1,c2,c3,…,cm} {r} = Î c ( c , c , c , . . . , c ) { 0 , 1 } 1 2 3 n where = Î r ( r , r , r , . . . , r ) { 0 , 1 } 1 2 3 m

37. PUF structure • Use of PUFs on RFID tags to securely store keys • 800 challenge-response pairs to uniquely identify over 109 chips

38. Tag authentication • Use sets of challenges and responses to authenticate tags • The response bit string can be compared with that stored in a secure database • Similarly to a one time pad, challenges can not be used again

39. Backend support • A secure backend database is required to store challenge response pairs • A secure method of distributing challenge response pairs are required • Labels need to be characterised prior to deployment

40. Lightweight hardware • Use XOR operation to allow challenge sets to be reused • simple to implement and low computation complexity

41. Mutual authentication • Use Reader generated Random numbers • Reuse hardware on tag (CRC generator) • Achieves mutual authentication and prevents unauthorised users from obtaining tag EPC

42. Specialised RFID tag antenna design Tag Constraints Small UHF Animal Ear Tag (pigs) Small HF Animal Ear Tags (pigs, sheep) Compact Metal Mount Tags (UHF) Dual Frequency Tag Antennas Overview of the latest RFID Research 21st March 2007

43. RFID Tag Constraints • Consist ofBasic requirement:- Compact- Reliable- Inexpensive

44. Small UHF Animal Ear Tags Overview of the latest RFID Research 21st March 2007

45. A Simple Loop Antenna Front view Back view

46. UHF ear tag

47. Small HF Animal Ear Tags Overview of the latest RFID Research 21st March 2007

48. HF ear tag

49. Compact Metal Mount UHF Tag Overview of the latest RFID Research 21st March 2007

50. Metallic Environment • Metallic Environment • Surrounding • Warehouses full of metallic shelves • Industrial area with heavy machinery • Object to be identified • Canned food • Metallic mechanical parts • Metallic beer kegs • Challenge • To get sufficient fields to reach RFID tag antenna near metal.