FH-Card im Handy: NFC-basierte Zutrittssysteme Christof Arnosti & Dominik Gruntz Institut für Mobile und Verteilte Systeme

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1 FH-Card im Handy: NFC-basierte Zutrittssysteme Christof Arnosti & Dominik Gruntz Institut für Mobile und Verteilte Systeme

2 NFC in the Press 5 May

3 NFC in the Press Google Trends Google NFC 5 May

4 NFC Experience at FHNW 2005/06 First NFC demonstrator (Siemens CX70 Emoty) NFC was included in a removable cover 2009/10 Mobile Payment project (Nokia 6131 NFC) touch'n'pay Self Service Shop (together with NEXPERTS / e24) Supported by the Hasler foundation NFC Forum Global Competition: First price in the category "The Best NFC Service of the Year 2010" 2010/11 Android Nexus S (with NFC) Tag reading/writing and P2P (several publications) 2012 Access Control (Siemens: MIFARE on NFC devices) 2013 MOONACS (Bixi / KTI) 2014 ibeam P2P (ibeam Solutions GmbH / AFF)

5 AGENDA NFC Device Operating Modes What is NFC? NFC Architecture What is the Secure Element? MOONACS: Mobile on/offline Mobile on/offline NFC based ACS Variant 1: HCE Variant 2: Device Fidelity 5 May

6 What is NFC NFC (Near Field Communication) Communication technology based on radio waves at MHz Compatible to ISO/IEC A (Mifare), B and F (FeliCa) Short range (<= 10 cm theoretical) Effective: 1-4 cm Low speed (106 / 216 / 414 kbps) => 13-50KBytes per sec Effective: 24 kbps => 3KB per sec Low friction setup (no discovery and no pairing as with Bluetooth) Setup-time < 0.1 Sec Standardization: NFC Forum (founded 2004 by NXP, Sony, Nokia) Definition of standards Popularization of NFC Today: More than 150 members 5 May

7 NFC Applications Smart Poster Reading data from a tag (comparable to QR-code-reading) Tasks Use NFC tags to automate tasks (e.g. set volumes, set alarms, etc) or to configure a WiFi network 5 May

8 NFC Applications Device Connection ear-phones, speakers, cameras or printers (Bluetooth connection initiated by NFC) Sharing Data Videos, pictures, business cards, coupons 5 May

9 NFC Applications Access Control Emulation of a contactless card Mobile Payment Emulation of a contactless card 5 May

10 NFC Device Operating Modes Reader-Writer Mode Peer-To-Peer Mode Tag/Card Emulation Mode 5 May

11 NFC Device Operating Modes Reader-Writer Mode Mobile Device is able to read external tags/smartcards, Device becomes RFID reader/writer (and can launch applications) Tag content: Text, URI (WebLink, Phone Number), SmartPoster Like QR-Codes, but faster Tags No need to launch an application With Android, an intent is thrown if a tag is detected Different form factors for NFC tags: tags, stickers, cards, key fobs, clocks Supported Technologies: ISO A/B, Mifare Ultralight, Classic/Standard 1K/4K NXP DESFire, Sony Felica, etc. => NFC Forum Specs define how NFC Messages are stored 5 May

12 NFC Device Operating Modes Peer-To-Peer Mode Bidirectional P2P connection to exchange data between devices Proximity triggered interactions Technologies S-Beam (Samsung): Android Beam: NFC + Wifi direct NFC + Bluetooth Standard: SNEP (Simple NDEF Exchange Prot.) Applications Exchange of vcards (e.g. XING) Hand-over of Tickets & P2P Payment Web-page sharing, Youtube-video-sharing Application sharing Exchange of device info in order to establish a faster connection automatically (e.g. Bluetooth) 5 May

13 NFC Device Operating Modes Tag/Card Emulation Mode Device emulates a passive tag (typically a smart card) Device can emulate (contain) multiple smartcards Reader can t distinguish between real smartcard & tag emulation Android: Emulated tag can be read only if screen is on Examples Access to the farm shop (Legic key) Oyster-Card, London Visa paywave Payment System Google Wallet, ApplePay, Tapit NFC Swatch 5 May

14 AGENDA NFC Device Operating Modes What is NFC? NFC Architecture What is the Secure Element? MOONACS: Mobile on/offline Mobile on/offline NFC based ACS Variant 1: HCE Variant 2: Device Fidelity 5 May

15 NFC Device Architecture Structure of a NFC device Host-Controller Application Execution Environment (AEE) Controls UI, Communication and peripheral devices (Phone OS) NFC-Controller Contactless Front-end (CLF) Converter between HF signal and digital data Secure Element Trusted Execution Environment (TEE) Secure environment to execute and store security relevant applications and data App 1 NFC Controller Host- Controller NFC API Antenna App 2 Secure Element 5 May

16 Secure Element Secure Element nonremovable removable emulated Embedded Hardware (Secure IC) UICC over SWP (Secure SIM) MicroSD- Card (Secure MC) Bluetooth Stickers Micro-USB Stickers 5 May

17 AGENDA NFC Device Operating Modes What is NFC? NFC Architecture What is the Secure Element? MOONACS: Mobile on/offline Mobile on/offline NFC based ACS Motivation Variant 1: HCE Security Variant 2: Device Fidelity Summary 5 May

18 MOONACS: Mobile on/offline NFC based ACS Project Description Mobile based access control Access Point not connected Based on Host Card Emulation Online: Server is contacted Offline: Access Tokens Variant to a TapIt solution, but Globally applicable Independent of Swisscom Partners Bixi Systems Supported by CTI/KTI 5 May

19 FHNW access now: Online reader 5 May

20 1. FHNW access now: Offline reader 2. 5 May

21 Moonacs basics Door has no own connection to a server 5 May

22 Bixi Online Solution: TapIt NFC solution by Swisscom Uses SIM-Card as smartcard, mobile phone provides NFC connectivity Partnership with salt, sunrise For Access Control Systems: Emulation of classic card on SIM Get rights for offline doors via refiller terminal or via mobile network Possible to instantly deactivate card over mobile network (if connected) Needs phone battery (phone can be shut down) Otherwise like normal access card IDConnect Product by LEGIC to allow MNO-independent sim cart solutions. 5 May

23 Motivation for Moonacs Less hardware for customers No connection between door and server needed No more refilling Independent of 3rd party companies Mobile Network Operators LEGIC IDConnect Internationally scalable Different security levels Host Card Emulation DeviceFidelity 5 May

24 HCE Variant 5 May

25 HCE Variant: Online Authentication Authorization 5 May

26 HCE Variant: Offline Rights update 5 May

27 HCE Variant: Offline Authentication / Authorization 5 May

28 Security Critical for Access Control Systems! Assumptions The smartphone is insecure (digitally and physically) All connections are insecure The BIXI Secure Server is secure The reader is secure Analyzed attack vectors: Digital attacks (no physical access to the mobile) Physical attacks (physical access to the mobile) 5 May

29 Security: What to protect? Indirect communication between reader and server Authenticity of the messages which are sent over untrusted connections and devices Symmetric cryptography Authentication of the mobile Public / private cryptography, private key on mobile 5 May

30 Theft of the smartphone Attack: an attacker steals the smartphone with the intent to use it to open doors Preventions Only allow the software to operate when the phone is unlocked Online access can be disabled instantly on the server side Offline access can be disabled by revocation of rights as soon as the phone has an online connection Compared with card based systems: More secure 5 May

31 Theft of cryptographic secrets Attack: an attacker uses malware to extract the private key from the smartphone With this information, an attacker can authenticate himself as the attacked smartphone Preventions The private key can be stored securely Hardware-based KeyStore since Android 4.3 (model dependent) special microsd cards Bluetooth tokens But if the Hardware based KeyStore is not present this means the user would have to use special hardware Compared with card based systems: Less secure 5 May

32 Proxy attack (Physical) Attack: an attacker uses two smartphones to «extend the reach» of NFC over the internet NFC Preventions Only allow the software to operate when the phone is unlocked Compared with card based systems: More secure 5 May

33 Proxy attack (Software) Attack: an attacker installs malware on the users phone. He then uses live information from the users phone transferred over the internet to simulate a legitimate request. Preventions Shown later in the presentation Compared with card based systems: Less secure 5 May

34 Security New technology based on software This means some advantages, some disadvantages + «Always connectible» of card no longer true - All purpose device (smartphone) - can be attacked in software 5 May

35 DeviceFidelity Variant SmartSD card (Secure Element on MicroSD card) Communication via NFC and from Smartphone app Secret information on DeviceFidelity Provides security against software attacks (proxy / key theft) 5 May

36 DeviceFidelity Variant Activate NFC 5 May

37 DeviceFidelity Variant Sends request data 5 May

38 DeviceFidelity Variant Deactivates NFC 5 May

39 DeviceFidelity Variant Prepares authentication 5 May

40 DeviceFidelity Variant Reads authorization request 5 May

41 DeviceFidelity Variant Get authorization data (Online case) 5 May

42 DeviceFidelity Variant Write authorization data 5 May

43 DeviceFidelity Variant Enable NFC 5 May

44 DeviceFidelity Variant Reads authentication & authorization data 5 May

45 DeviceFidelity Variant 5 May

46 Why DeviceFidelity? Secrets stored in a secure place No possibility to use a software proxy, since the authentication can t be done by the smartphone but only by NFC 5 May

47 Comparison Card TapIt Host Card Emulation Device Fidelity NFC on (Theft / physical proxy) Always on Always on On unlocked device On user interaction Key security Secure Secure Device dependent (mostly secure on modern phones) Software proxy Not possible Not possible Insecure if and only if attacker has control over device Offline door right refilling Time to open (Important for usability) Terminal system dependent Over Mobile Network or terminal system dependent Online over smartphone Online: Phone connection dependent. Offline: very short Secure Secure Online over smartphone Like Host Card Emulation + ~ sec 5 May

48 Project status Already implemented by FHNW: Online part of the protocol Server Android application DeviceFidelity application Reader simulator Currently at work by Bixi Reader Connection between server and backend To be implemented by FHNW and Bixi: Offline part of the protocol To be coming: Prototype at IMVS 5 May