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Physical Security IIS 2 Overview Smart cards RFIDs Attacks (Semi)-Natural tags Conclusions.

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Presentation on theme: "Physical Security IIS 2 Overview Smart cards RFIDs Attacks (Semi)-Natural tags Conclusions."— Presentation transcript:

1 Physical Security

2 IIS 2 Overview Smart cards RFIDs Attacks (Semi)-Natural tags Conclusions

3 Smart Cards

4 IIS 4 Smart cards 85.6 mm mm 0.76 mm [And96] R. J. Anderson and M. G. Kuhn. Tamper resistance - A cautionary note. In 2nd Int. Usenix Workshop on Electronic Commerce, pages 1-11, Oakland, California, Nov USENIX Association. Broken!

5 IIS 5 What makes the card smart? CPU (8, 16, 32 bit) Memory (RAM, ROM, EEPROM, Flash) I/O channel (Contact/Contact less) Cryptographic co-processor On card devices (Fingerprint, display) Standards (ISO 7816, GSM, EMV, VOP)

6 IIS 6 Main security features Symmetric crypto Asymmetric crypto relatively slow Hardware random number generator Hardware tamper resistance X-tal clock vulnerable Life cycle management

7 IIS 7 Communication ISO : 9600 bps : slow USB : bulky Bluetooth: power Biometrics: slow

8 IIS 8 Displays Plastic, glass Emissive, non-emissive Refresh, bi-stable Segment, dot-matrix Problems: connections, yield, power, thickness, price! [Pra01] D. Praca and C. Barral. From smart cards to smart objects: the road to new smart technologies. Computer Networks, 36(4): , Jul

9 IIS 9 Clock & Power Clock »Xtal 0.6 mm »MEMS (0.002% acc.) Battery »Thickness »power density »when to recharge

10 IIS 10 Integration is hard Display Button 32-bit CPU Large memory Battery Comms >> 25mm 2 Photo: Philips Semiconductors


12 IIS 12 What is an RFID tag? Antenna + small chip in ambient field Passive, replies to queries only Can be used for almost anything »Supply Chain Management & Checkout (Wallmart, Benetton) »Homeland security »User convenience »Access to buildings Nokia 6131 NFC

13 IIS 13 Passport application

14 IIS 14 Privacy issues Sniffing »Data collection in proximity (skimming) »Correlate data from different tags Counter measures »Shield antenna in passport with tinfoil »Encrypt the template with MRZ data »Reduce transmit range »Light controlled on/off switch »Long and short range interface »Time delayed transmit of sensitive info [Bir07] N. Bird, C. Conrado, J. Guajardo, S. Maubach, G. Jan Schrijen, B. Skorić, A. M. H. Tombeur, P. Thueringer, and P. Tuyls. ALGSICS - combining physics and cryptography to enhance security and privacy in RFID systems. In F. Stajano, C. Meadows, S. Capkun, and T. Moore, editors, 4th European Workshop on Security and Privacy in Ad-hoc and Sensor Networks (ESAS), volume LNCS 4572, pages , Cambridge, UK, Jul Springer. Watch this video

15 Attacks [Wit02] M. Witteman. Advances in smartcard security. Information Security Bulletin, pages , Jul

16 IIS 16 Attacks Operational »Blackmail »Burglary »Bribery Technical »Logical »Physical »Side channel Attackers »I: Clever outsiders »II: Knowledgeable insiders »III: Funded Organisations

17 IIS 17 Logical attacks The code is too complex »Hidden commands »Parameter poisoning & Buffer overflow »Malicious or buggy applets »Protocol problems (e.g. retransmit) »Proprietary crypto Counter measures »Structured design & code inspection »Formal methods »Testing

18 IIS 18 Example: RFID virus There is a large amount of code Generic protocols and facilities Back end data bases So the usual attacks: »Buffer overflow »SQL injection ;shutdown-- Dont trust data from RFID tag… [Rie06] M. R. Rieback, B. Crispo, and A. S. Tanenbaum. Is your cat infected with a computer virus? In 4th Annual IEEE Int. Conf. on Pervasive Computing and Communications (PerCom), pages , Pisa, Italy, Mar IEEE Computer Society. Best paper award

19 IIS 19 Physical attacks The circuitry is complex and vulnerable »Chemicals & etching »SEM Voltage contrast »Probe stations »Focused Ion Beam (FIB) to make probe pads Counter measures »Reduced feature size (100nm) »Multi layering »Protective layers »Sensors »Bus scrambling

20 IIS 20 Low cost physical attacks Block EEPROM writes by isolating Vpp Rent focused Ion beam [And97d] R. J. Anderson and M. Kuhn. Low cost attacks on tamper resistant devices. In 5th Int. Workshop on Security Protocols, volume LNCS 1361, pages , Paris, France, Apr

21 IIS 21 Side channel attacks Physical phenomena can be measured »Power »EM radiation (X-ray, light, sound) »Time and changed »Voltage (example later) »Frequency (example later) [Vua09] M. Vuagnoux and S. Pasini. Compromising electromagnetic emanations of wired andWireless keyboards. In 18th USENIX Security Symp., pages 1-16, Montreal, Canada, Aug USENIX Assoc. Watch this video

22 Timing attack Exponentiation by square and multiply »for i = n 2 downto 0 » X = X 2 » if (d[i] == 1) then » X = X*M Power trace shows bits 1 in the key IIS 22

23 Simple power analysis 16 rounds DES Rounds 2 & 3 IIS 23 [Koc99] P. C. Kocher, J. Jaffe, and B. Jun. Differential power analysis. In M. J. Wiener, editor, 19th Int. Conf. on Advances in Cryptology (CRYPTO), volume 1666 of LNCS, pages , Santa Barbara, California, Aug Springer.

24 IIS 24 Differential power attacks Difference in the third cycle due to difference in input value for encryption

25 IIS 25 Active attacks : Power Dip read a 0 as a 1 Protection measure »Check VCC & raise an alarm if it drops »Problem: Fast transients during start-up may raise false alarms Reading threshold Stored value of logical zero vcc gnd A power Dip at the Moment of reading a memory cell

26 IIS 26 Active attacks : Clock Glitch Dump all of the memory Replace 5MHz pulse by 4 pulses of 20MHz: 1.b = answer_address 2.a = answer_length 3.If (a == 0) goto 8 4. transmit(*b) 5. b=b+1 6. a=a-1 7.goto 3 [And97d] R. J. Anderson and M. Kuhn. Low cost attacks on tamper resistant devices. In 5th Int. Workshop on Security Protocols, volume LNCS 1361, pages , Paris, France, Apr Glitch here

27 IIS 27 Countermeasures Hardware »Lower power signals »Increase noise levels »Introduce timing noise Software »Parallelism »Introduce random delays »Constant time execution »Blinding intermediate values

28 IIS 28 Countermeasures Make attacks harder but not impossible Hard to get right Expensive to implement

29 IIS 29 Out of the box thinking The humble Capacitor »Emanates acoustic signals »Sensitive to shocks and vibration »C A / d

30 IIS 30 Listen to a PC multiplying Freeze 1500 μF capacitor

31 IIS 31 Shaking a smart card....

32 IIS 32 Attackers business case Attack Class EquipmentCostSucc. Rate Devel. Time Exec. Time LogicalPC, card reader1-10KLowWksMins PhysicalPC, Probe Station, SEM, FIB,Microscope, Chemistry Lab 100K- 1M HighMnthsDays Side Channel PC, Oscilloscope, Function Gen. 10K- 100K Med.MnthsHours Rental!

33 IIS 33 Design guidelines Define the level of security needed Perform a risk analysis Consider the attackers business case Use the right technologies Build in fraud management Design recovery and fall-back Consider the overall system

34 IIS 34 IBM 4758 Crypto Coprocessor Rolls Royce of secure devices Tamper sensing barrier Keys move in the RAM Temperature & X-ray sensor Solid aluminium case & epoxy potting low pass filter on power supply Used in ATMs Hacked! [Cla03b] R. Clayton and M. Bond. Experience using a Low-Cost FPGA design to crack DES keys. In 4th Int. Workshop on Cryptographic Hardware and Embedded Systems (CHES), volume LNCS 2523, pages , Redwood Shores, California, Springer.

35 (Semi) Natural tags

36 IIS 36 Finger printing [Buc05] J. D. R. Buchanan, R. P. Cowburn, A.-V. Jausovec, D. Petit, P. Seem, G. Xiong, D. Atkinson, K. Fenton, D. A. Allwood, and M. T. Bryan. Forgery: 'fingerprinting' documents and packaging. Nature, 436(7050):475, Jul

37 IIS 37 Philips Coating PUF [Sko08] B. Škorić, G.-J. Schrijen, W. Ophey, R. Wolters, N. Verhaegh, and J. van Geloven. Experimental hardware for coating PUFs and optical PUFs. In P. Tuyls, B. Škorić, and T. Kevenaar, editors, Security with Noisy Data - On Private Biometrics, Secure Key Storage and Anti-Counterfeiting, pages Springer London,

38 MEMS particles 1x1x12 m particles, shapes Church and school roof, power line grease/gel Jewellery fluid Spray vandals/thiefs Smart water IIS 38 [Kay92] P. H. Kaye, F. Micheli, M. Tracey, E. Hirst, and A. M. Gundlach. The production of precision silicon micromachined non-spherical particles for aerosol studies. Journal of Aerosol Science, 23(Suppl 1): , Watch this video

39 IIS 39 Conclusions Affordable tamper resistance technology exists Getting it right is difficult Out of the box thinking required

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