AN EXTENSIBLE AND PRIVACY- PRESERVING MOBILE ID Michael Hlzl, MSc - PowerPoint PPT Presentation

AN EXTENSIBLE AND PRIVACY- PRESERVING MOBILE ID Michael Hölzl, MSc Institute of Networks and Security, JKU Linz IKT Sicherheitskonferenz 2017 26. September 2017, Villach

Digital Identity: State of the Art  OpenID: some (large) providers, many (small) consumers  Facebook  Google  ...  FIDO  U2F  UAF  Governmental eIDs (German ePerso, Austrian “Bürgerkarte”, etc.) → optimized for web page login, not physical identification Extensibility in a Privacy-preserving eID 2

Motivating Scenario: Convergence of Security-Critical Services Extensibility in a Privacy-preserving eID 3

Mobile eID Use Case 1: Driving license verification by Police  All relevant attributes need to be presented, e.g. ID number:  Name 123456789  Date of birth Surname:  Full-resolution photo EINSTEIN  Vehicle classes Givenname: Albert  Restrictions/limitations  ... Date of Birth: Sex: 1879-03-14 M  Offline ID attributes transfer and Place of Birth: GENUINE offline verification Ulm, Germany Citizenship:  Should also work when mobile USA, Switzerland phone battery is empty! Signature: Extensibility in a Privacy-preserving eID 4

Mobile eID Use Case 2: Age Verification  Age verification by e.g.  Automated vending machines ID number:  Bouncers at clubs 123456789  Entrance staff for birthday Surname: rebate promotions EINSTEIN Givenname:  Only age attribute should be Albert transferred in privacy- Date of Birth: Sex: sensitive manner 1879-03-14 M > 16 years Place of Birth: GENUINE Ulm, Germany Citizenship: USA, Switzerland Signature: Extensibility in a Privacy-preserving eID 5

Mobile eID Use Case 3: Time-based Ticket for Public Transport  Typical for public transport  Monthly ID number:  Yearly 123456789  (any time period) Surname: EINSTEIN  No identifiers should be Givenname: transferred Albert  Location traces are highly Date of Birth: Sex: sensitive personal data 1879-03-14 M > 16 years Place of Birth: GENUINE Ulm, Germany Citizenship: USA, Switzerland Signature: Extensibility in a Privacy-preserving eID 6

Extensible and Privacy-preserving Mobile eID Extensibility in a Privacy-preserving eID 7

Building Blocks  NFC Secure Element (SE)  Protect identity keys & integrity assurances  Code isolation  Can be powered by the NFC field  Downside: constrained performance (see [1])  Attribute-based Credentials (ABC)  Issuance of attributes within a cryptographic container (credential) by trusted authority  Allows selective disclosure (SD) of these attributes  Downside: operations can become time-consuming (especially on an SE, e.g. [2]) Extensibility in a Privacy-preserving eID 8

Extensibility and Privacy-preserving Mechanisms  Domains  eID derives pseudonym for each enrolled ID number: 123456789 domain Surname:  Domain can add data attributes to eID (e.g. EINSTEIN Givenname: transport ticket validity period) Albert  Trust-on-First-Use (TOFU) database protects derive against pseudonym linking  Profiles  Controlled by user  Defines the set of accessible attributes  Can be associated with a domain Extensibility in a Privacy-preserving eID 9

Secure Channel Protocols  Purpose  eID validation  Profile selection  Attribute exchange  We define two processes  Domain enrollment  Verification Extensibility in a Privacy-preserving eID 10

Protocols: Domain Enrollment  Initiated by eID holder on mobile device  User approves with PIN/password  Secure channel between SE and domain manager  Based on Alpár and Hoepmann in [3]  ABC to authenticate session keys  Use of the nonce of the selective disclosure (SD) mechanism  Combined with a domain pseudonym derivation Extensibility in a Privacy-preserving eID 11

Protocols: Domain Enrollment Extensibility in a Privacy-preserving eID 12

Evaluation  Storage Space on SE  Each enrolled domain requires: 1x EC-point, 1x profile description (e.g. 4 bytes for 32 attributes) ➔ 69 bytes  Computation times on SE  Domain enrollment  Verification Extensibility in a Privacy-preserving eID 13

Austrian mobile Driving License (AmDL)  Current prototype at research center u'smile Extensibility in a Privacy-preserving eID 14

Conclusion  Mobile eID for real-world identification  Possibility to use it for many services ID number: 123456789  Protocols for efficient attribute Surname: EINSTEIN exchange Givenname: Albert Date of Birth: Sex: 1879-03-14 M Place of Birth: Ulm, Germany  Protocols can be run on smart cards Citizenship: USA, Switzerland Signature: within reasonable time (below 2s) Extensibility in a Privacy-preserving eID 15

AN EXTENSIBLE AND PRIVACY- PRESERVING EID Michael Hölzl, MSc Institute of Networks and Security, JKU Linz JOHANNES KEPLER hoelzl@ins.jku.at UNIVERSITÄT LINZ Altenberger Str. 69 4040 Linz, Österreich www.jku.at

Bibliography [1] M. Hölzl, R. Mayrhofer, and M. Roland. Requirements for an Open Ecosystem for Embedded Tamper Resistant Hardware on Mobile Devices. In Proceedings of International Conference on Advances in Mobile Computing & Multimedia , MoMM ’13, pages 249–252. ACM, 2013. [2] P. Vullers and G. Alpár. Efficient Selective Disclosure on Smart Cards Using Idemix. In Policies and Research in Identity Management (IDMAN) , pages 53–67. Springer Berlin Heidelberg, Apr. 2013. [3] G. Alpár and J.-H. Hoepman. A Secure Channel for Attribute-based Credentials: [Short Paper]. In Proceedings of the 2013 ACM Workshop on Digital Identity Management, DIM ’13, pages 13–18. ACM, 2013. Extensibility in a Privacy-preserving eID 17

Credits  Icons  SIM Card by Arthur Shlain from the Noun Project  People pattern by Gregor Cresnar from the Noun Project  Agreement by Chameleon Design from the Noun Project  Smart Phone by Emily Haasch from the Noun Project  Airplane Ticket by Creative Stall from the Noun Project  Bus tickets by Iulia Ardeleanu from the Noun Project  Loyalty Card by icon 54 from the Noun Project  Business card by Karthik Aathis from the Noun Project Extensibility in a Privacy-preserving eID 18