Digitale Ausweise fr physische Identifikation? Univ.-Prof. Dr. Ren - PowerPoint PPT Presentation

Digitale Ausweise für physische Identifikation? Univ.-Prof. Dr. René Mayrhofer und Michael Hölzl, MSc Institut für Netzwerke und Sicherheit, Johannes Kepler Universität Linz Vortrag zur IKT-Sicherheitskonferenz 2016 2016-10-11 11:15, St. Johann im Pongau

Motivating Scenario: Convergence of Security-Critical Services 2016-10-11 Digitale Ausweise für physische Identifikation 2

Digital Identity: State of the Art  OpenID: some (large) providers, many (small) consumers  Facebook  Google  ...  FIDO  U2F  UAF  Österreichische Bürgerkarte → all optimized for web page login, not physical identification 2016-10-11 Digitale Ausweise für physische Identifikation 3

Motivating Scenario: Convergence of Security-Critical Services 2016-10-11 Digitale Ausweise für physische Identifikation 4

Digital (Photo-) ID for Physical Identification  Online solution: MIA (My Identity App) by Österreichische Staatsdruckerei  App for smart phones for using „virtual“ identity cards  requires online connectivity for verifying these documents  Current project in JRZ u‘smile: AmDL (Austrian mobile Driving License) with partners  A1 Telekom  Drei-Banken-EDV  LG Nexera  NXP Semiconductors  Österreichische Staatsdruckerei  SBA Research 2016-10-11 Digitale Ausweise für physische Identifikation 5

AmDL Use Case 1: Identity Verification by Police  All relevant attributes need to be presented, e.g. ID number:  Name 123456789  Date of birth Surname: EINSTEIN  Full-resolution photo  (optional) Biometric identifiers Givenname: Albert  Vehicle classes  Restrictions/limitations Date of Birth: Sex: 1879-03-14 M  ... Place of Birth:  Only accessible to officially GENUINE Ulm, Germany certified readers Citizenship: USA, Switzerland  Offline ID attributes transfer Signature: and offline verification  Should also work when mobile phone battery is empty! 2016-10-11 Digitale Ausweise für physische Identifikation 6

AmDL 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  Not the full date of birth! Place of Birth: GENUINE Ulm, Germany  Support binary yes/no answers for specific use case Citizenship: USA, Switzerland Signature: 2016-10-11 Digitale Ausweise für physische Identifikation 7

AmDL Use Case 3: Time-based Ticket for Public Transport  Typical for public transport  Monthly  Yearly  (any time period)  No identifiers should to be transferred (no name, date of birth, etc.) for privacy reasons  Location traces are highly sensitive personal data  Still need to support typical operations  Unforgeability  Revocation (loss, theft, non- payment, etc.) 2016-10-11 Digitale Ausweise für physische Identifikation 8

Requirements Functional Mobility  Real-world identification  Offline  One-to-many  Power-off  Revocation  Scalability Security Privacy  Key confidentiality  Unlinkability  Unforgeability  User control  Communication protection  Privacy-preserving attribute queries  State-of-the-art cryptography 2016-10-11 Digitale Ausweise für physische Identifikation 9

Extensible and Privacy-preserving Mobile eID 2016-10-11 Digitale Ausweise für physische Identifikation 10

Technologies  NFC Secure Element (SE)  Protect identity keys  Integrity assurances  Code isolation  Group signatures  Members can sign on behalf of the group  Anonymity in the group  Unlinkability 2016-10-11 Digitale Ausweise für physische Identifikation 11

Privacy-preserving Identification ID number: ID number: 123456789 123456789 Surname: Surname: EINSTEIN EINSTEIN Givenname: Givenname: Albert Albert Date of Birth: Sex: Date of Birth: Sex: 1879-03-14 M 1879-03-14 M > 16 years Place of Birth: Place of Birth: GENUINE Ulm, Germany GENUINE Ulm, Germany Citizenship: Citizenship: USA, Switzerland USA, Switzerland Group Signature: Signature: signature of national eID 2016-10-11 Digitale Ausweise für physische Identifikation 12

Privacy-preserving Identification  Privacy-preserving attribute queries ID number:  Attribute inequality query ID number: 123456789 123456789  E.g. above 16 years old? Surname: Surname: EINSTEIN EINSTEIN  Attribute equality query Givenname: Givenname:  E.g. Austrian citizen? Albert Albert Date of Birth: Sex: Date of Birth: Sex:  Group membership query 1879-03-14 M 1879-03-14 M > 16 years  E.g. enrolled to public transport system? Place of Birth: Place of Birth:  E.g. allowed to drive this vehicle class (for GENUINE GENUINE Ulm, Germany Ulm, Germany renting a car)? Citizenship: Citizenship: USA, Switzerland USA, Switzerland == Austrian Signature: Signature: 2016-10-11 Digitale Ausweise für physische Identifikation 13

Group/Division Membership ID number: 123456789 Surname: EINSTEIN Givenname: Albert Date of Birth: Sex: 1879-03-14 M Place of Birth: Ulm, Germany Citizenship: USA, Switzerland Signature:  Extensibility of eID for the use with numerous groups/divisions  e.g. loyalty card, public transport ticket, students card, etc.  Challenge: unlinkability, untraceability 2016-10-11 Digitale Ausweise für physische Identifikation 14

Group/Division Membership  Approach  Pseudonym concept of Austrian Bürgerkarte ID number: 123456789  Each division has an identifier Surname:  eID generates pseudonym for division EINSTEIN id d Givenname: Albert id u, d = H ( id u || id d ) derive  Divisions can add data to eID  Protected with TOFU database C = E ( pk d ,id u ,d ⊕ n || D ) where n is a random nonce and D are data attributes 2016-10-11 Digitale Ausweise für physische Identifikation 15

Extensible and Privacy-preserving Mobile eID 2016-10-11 Digitale Ausweise für physische Identifikation 16

Revocation  Scenarios  User lost her phone (the eID)  Revocation done by user  eID has been withdrawn (e.g. holder deceased)  Done by central authorities  Additional threat: identity theft 2016-10-11 Digitale Ausweise für physische Identifikation 17

Revocation  Usual approach: revocation list  Problem: no ID in group signature  Additional challenges: 1. Items on the revocation list might loose anonymity 2. Additional computation effort 3. Could weaken unlinkability 4. Growing revocation list 2016-10-11 Digitale Ausweise für physische Identifikation 18

Preserving Privacy beyond Revocation  New revocation concept based on  Offline revocation token generation on SE  Bloom filter  Features of our approach  Scalability through efficient revocation check (O(1))  Backwards unlinkability  Verifier-local revocation check  Offline verification 2016-10-11 Digitale Ausweise für physische Identifikation 19

Preserving Privacy beyond Revocation  Revocation list based on bloom filter  Probabilistic data structure  Provides scalability  Revocation token difficult to restore { x, y, z } 0 1 0 1 1 1 0 0 0 0 0 1 0 1 0 0 1 0 w 2016-10-11 Digitale Ausweise für physische Identifikation 20

Preserving Privacy beyond Revocation Revocation filter { x, y, z } 0 1 0 1 1 1 0 0 0 0 0 1 0 1 0 0 1 0  Verifier → Prover  Random identifier ch id v and challenge  Prover → Verifier rt i, v = H ( id v || H ( id u, se || gpk || c i ))  Generated revocation token σ= sign ( gsk i ,ch || rt i,v )  Validation of group membership 2016-10-11 Digitale Ausweise für physische Identifikation 21

Preserving Privacy beyond Revocation  Computation times 2016-10-11 Digitale Ausweise für physische Identifikation 22

Open Issue: Backup of Digital Identity 2016-10-11 Digitale Ausweise für physische Identifikation 23

LIKE ME! Friends with Faces Next Step: Trust us, we have Digital Identity in the Cloud a Privacy Shield! 2016-10-11 Digitale Ausweise für physische Identifikation 24

You can search And we have for everybody assistants Next Step: Data stored for Digital Identity in the Cloud future improvement of all our services 2016-10-11 Digitale Ausweise für physische Identifikation 25

We are looking for interested partners: Next Step: - technology - use cases Digital Identity in the Cloud - funding ... d i g i t a l s e r v i c e d i s c o v e r y , 1 d i s t r i b u t e d n e t w o r k s e t u p [ g l o b a l l y u n i v e r s a l ] [ o p e n ma r k e t ] certify identity 7 V E R I F I E R P E R S O N A L A G E N T T P M D i g i t a l 4 5 2 w o r l d [ l o c a l l y d i f f e r e n t ] 3 B I O M E T R I C 6 S E N S O R T P M provide unique ID 8 trigger reaction P h y s i c a l w o r l d 2016-10-07 Sicherheit in der Digitalisierung 26