Embedded Wireless Sensors Tony Arous Vincent Yu

Recap  RFID– Radio Frequency Identification  Sensors help to easily keep track of various information PeoplePeople ProductsProducts Chemical CompositionChemical Composition  Each application requires a different type of sensor

Possible Uses on Humans  Identification  Security  Tracking  Monitoring vital signs  Diabetes monitoring  Medical purposes

Focuses on Security  How secure is RFID? Encryption is weak and can easily be spoofed in hoursEncryption is weak and can easily be spoofed in hours  Example: Exxon Speedpass and Ford 40bit encryption made by TI40bit encryption made by TI With a microreader and laptop, these information can be extracted from these devicesWith a microreader and laptop, these information can be extracted from these devices

Cracking the Code

Security Problems  A more secure system is needed  Must limit what people have access to vital, secret information  Some RFID tags can be read at any time with no notification

Security Problems  Unique ID for every individual item in stores ID’s will then be tied to credit cardsID’s will then be tied to credit cards Security problems if tags are stolen, lost or removed from the productsSecurity problems if tags are stolen, lost or removed from the products  An effective method of destroying stored information after some time is needed

Privacy Issues

Current Security Problems  Today’s RFID systems use a simple encryption technique  Over 150 million RFID tags made by TI are being used today  All tags are based on the same encryption  Researchers cracked the SpeedPass technology in 16 minutes

Resolutions  Key length of the encryption should be the standard Advanced Encryption Standard (AES) in its 128-bit form  Shielding the RFID from scanners  Scanners to deactivate RFID chips when leaving the store

Problems with the Resolutions  Longer encryption lengths means higher costs, more power consumption and a possibility that it will not be backwards compatible with older devices  Shielding the device is not a good method due to added size and potentially be an inconvenience to users. This would also not be workable if the RFID would be implanted into humans  Deactivating tags is not wanted for some tags (Speedpass & Fast Lane)

Integrating Solutions  The scanners read encrypted information from RFID chip which sends it to a computer to decrypt.  The computer will then determine what information to pass to the scanner

Integrating Solutions  A computer will be able to process more information and stronger encryption codes than the scanner can

More Concepts  Other methods may work to achieve the same goal, but each one offers its own disadvantages.

Tag/Reader Combinations  Potential Solution: Restrict a tag to communicate to specific readersRestrict a tag to communicate to specific readers  Tags would maintain static information about which readers have access  Problems: Upgraded technologyUpgraded technology Expensive to require specific readersExpensive to require specific readers

Proposed Solution  Follow the method used in medical RFID technology  Communicate with authentication server to verify information  Internet connection will be necessary Additional technology neededAdditional technology needed  WiFi, Ethernet, Bluetooth Create a more efficient and secure reader/tag systemCreate a more efficient and secure reader/tag system

Proposed Solution

Internals  Requirements Power consumption: < 20 uAPower consumption: < 20 uA Chip size: < 1 mm 2Chip size: < 1 mm 2 Low cost: 5 to 50 centsLow cost: 5 to 50 cents CompatibilityCompatibility

Internals

AES Module  On-demand and live calculation  8 bit architecture

Internals  Microcontroller: RISC Machine:RISC Machine:  12 bit instructions  4 bit data bus  32 registers  AES: Pre-existing technologyPre-existing technology

Questions from Last Time  Can IDs or the information they transmit be spoofed? Yes, we need to include preventative measures in our encryption techniques.Yes, we need to include preventative measures in our encryption techniques.  How can you ensure encryption when only a limited amount of data can be stored on a RFID tag? Data is either permanently stored or generated on-demand.Data is either permanently stored or generated on-demand. Encryption device will be permanent and then transmit modified data, reducing the need for more storage space.Encryption device will be permanent and then transmit modified data, reducing the need for more storage space.

More Questions  How will you reduce the number of collisions? We’ll discuss in more detail next time based on some new techniques being researched.We’ll discuss in more detail next time based on some new techniques being researched.  What is our goal? We are looking at this project from an investigative/research point of view. We hope to make suggestions to existing technology.We are looking at this project from an investigative/research point of view. We hope to make suggestions to existing technology.

Next Time…  Discuss some security techniques being researched now Juels-Pappo Banknote Protection SchemeJuels-Pappo Banknote Protection Scheme El Gamal cryptosystemEl Gamal cryptosystem Interleaved protocolInterleaved protocol

References  /2005/1/31/technology/ &sec=technology   graz.ac.at/aboutus/people/feldhofer/papers/melecon_slides.pdf  banknote-slides.pdf 