1. NFC Devices: Security and Privacy
Gerald Madlmayr, Josef Langer, Christian Kantner, Josef Scharinger
The Third International Conference on Availability, Reliability and Security
Speaker: Wei-Lun Huang

2. Outline Introduction What is NFC ? Technological aspects of NFC
Threat Model
Threats
Conclusion

3. Introduction
NFC (Near Field Communication) is a wireless proximity communication technology.
The major advantage of NFC over other wireless communication technology is simplicity.
Estimations show that by 2012 there are about 180 million mobile devices equipped with this technology.

4. What is NFC ? It’s a two-way communication technology based on RFID.
It’s a tag, and also a reader.
More point up authenticate of personal than RFID.

5. Applications of NFC

6. Wireless Communication Technology Compare
WiFi
Bluetooth
Infrared
NFC
Range
0 ~ 100 m
0 ~ 10 m
0 ~ 1 m
< 50 cm
Transfer rate
High
54 Mbps
Medium
1 Mbps
4 Mbps
Low
Security
Very High
Cost
Very Low

7. Technological aspects of NFC
Reader/Writer Mode (Proximity Coupling Device, PCD)
This mode allow the user to retrieve additional information.
Peer-to-Peer (Near Field Communication, NFC)
This mode allow two NFC enabled devices to establish a bidirectional connection to exchange contacts, Bluetooth pairing information or any other kind of data.
Card Emulation (Proximity Inductive Coupling Card, PICC)
This mode is useful for payment and ticketing applications for example.

8. Architecture of NFC integrated in a mobile device.

9. Threat Model – Use cases
Use of unique ID
External mode of secure element
Handset reads external tag
Data exchange using
Internal mode of secure

10. NFC Device Operating Modes – 1/2
Communication Flow
Operation Mode
Communication Interface
Use case
Use of unique ID
Handset providing data
Reader collecting data
Tag Emulation
Read/Write
ISO14443
Access
Loyalty
(2) External mode of secure element
Payment
(3) Handset reads external tag
Tag holding data
Handset reading tag/target
tag (emulation)
BT/WiFi-Config
VCard transfer
Smart Poster

11. NFC Device Operating Modes – 2/2
Communication Flow
Operation Mode
Communication
Interface
Use case
(4) Data exchange using
NFC
NFC target providing data
Handset collecting data
Peer (Target)
Peer (Init)
ISO14443
BT/WiFi-Config
VCard transfer
data exchange
(5) Internal mode of secure
element
Secure elements in the handset
Host Controller Application
Internal mode
Comm. channel to SE
OTA provisioning
Ticket upload
Money top up

12. Threat Model – Components and Trust Levels
Host controller
Applications can be given more trust by signing them with a code signing certificate to put them into a different security domain on the handset.
NFC controller
The communication flow between the secure elements and external readers or the host controller can be (re)routed.
Secure Element
The secure element is the only secure place in an NFC device.

13. Threat Model – Assets to be protected
The User’s privacy and personal information.
Address book, short messages e. g.
Operability of the device.
Voice and data connectivity e.g.
Functionality of the host controller and applications in the secure element.
Payment, access e.g.
Information transferred over the RF link.

14. Threats Denial of Service Relay data transferred over the RF
Skimming of applications in the secure element
Managing in-device security
Transactions over NFC peer link
Issues due to the fixed unique ID
Phishing

15. Threats - Denial of Service
It is a simply way to occupy the device.
Even it is a only error message, the device will still read it.
Some kind of mechanism controlled by user to turn on/off of the NFC reader/write functionality.

16. Threats - Relay data transferred over the RF
The smart card functionality could even be relayed if the battery was removed from the device.
This NFC transaction flight mode would be useful in case the device runs out of battery but the user still wants to use it for access or payment.

17. Threats - Skimming of applications in the secure element
Some feature allows 3rd party players also to see which other applications there are on the secure elements.
This is not an issue directly related to the NFC technology but more to the smart card industry.

18. Threats - Managing in-device security
Applications running on the host controller need to authenticate against the secure element before a communication can be established.
Use a certificate based authentication between the application running on the host and the applets in the secure element.

19. Threats - Transactions over NFC peer link
A plain data link with no security enables attackers to eave drop the communication and/or alter the data over the RF link.
Using a certificate based authentication or Diffie - Hellman Key exchange.

20. Threats - Issues due to the fixed unique ID
As the unique ID is specified in the standard for anti-collision, a simple hardware like OpenPICC simulates an arbitrary ID to spoof someone’s identity.
The ID can also be acquired by eaves dropping the communication between the reader and the smart card chip as it is not encrypted.
This issue could be bypassed by having a random number for anti- collision as already used for NFC targets and in e-passports ,so it cannot be used for tracking or identification.

21. Threats - Phishing
Attackers try to mislead users by social engineering.
This is a simple and inexpensive way to mislead the user.
Using signatures on tags and transporters would be suitable way to overcome this issue.

22. Conclusion The standardization is still ongoing.
As NFC devices and services do not only rely on a handset but also on lots of different parties, security and privacy issues should be already considered on the bottom level of technology if possible.