---
_id: '13904'
abstract:
- lang: eng
  text: In this paper, we introduce updatable anonymous credential systems (UACS)
    and use them to construct a new privacy-preserving incentive system. In a UACS,
    a user holding a credential certifying some attributes can interact with the corresponding
    issuer to update his attributes. During this, the issuer knows which update function
    is run, but does not learn the user's previous attributes. Hence the update process
    preserves anonymity of the user. One example for a class of update functions are
    additive updates of integer attributes, where the issuer increments an unknown
    integer attribute value v by some known value k. This kind of update is motivated
    by an application of UACS to incentive systems. Users in an incentive system can
    anonymously accumulate points, e.g. in a shop at checkout, and spend them later,
    e.g. for a discount.
author:
- first_name: Johannes
  full_name: Blömer, Johannes
  id: '23'
  last_name: Blömer
- first_name: Jan
  full_name: Bobolz, Jan
  id: '27207'
  last_name: Bobolz
- first_name: Denis Pascal
  full_name: Diemert, Denis Pascal
  id: '44071'
  last_name: Diemert
- first_name: Fabian
  full_name: Eidens, Fabian
  id: '25078'
  last_name: Eidens
citation:
  ama: 'Blömer J, Bobolz J, Diemert DP, Eidens F. Updatable Anonymous Credentials
    and Applications to Incentive Systems. In: <i>Proceedings of the 2019 ACM SIGSAC
    Conference on Computer and Communications Security - CCS ’19</i>. Proceedings
    of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS
    ’19. ; 2019. doi:<a href="https://doi.org/10.1145/3319535.3354223">10.1145/3319535.3354223</a>'
  apa: Blömer, J., Bobolz, J., Diemert, D. P., &#38; Eidens, F. (2019). Updatable
    Anonymous Credentials and Applications to Incentive Systems. <i>Proceedings of
    the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19</i>.
    26th ACM Conference on Computer and Communications Security, London. <a href="https://doi.org/10.1145/3319535.3354223">https://doi.org/10.1145/3319535.3354223</a>
  bibtex: '@inproceedings{Blömer_Bobolz_Diemert_Eidens_2019, series={Proceedings of
    the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19},
    title={Updatable Anonymous Credentials and Applications to Incentive Systems},
    DOI={<a href="https://doi.org/10.1145/3319535.3354223">10.1145/3319535.3354223</a>},
    booktitle={Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications
    Security - CCS ’19}, author={Blömer, Johannes and Bobolz, Jan and Diemert, Denis
    Pascal and Eidens, Fabian}, year={2019}, collection={Proceedings of the 2019 ACM
    SIGSAC Conference on Computer and Communications Security - CCS ’19} }'
  chicago: Blömer, Johannes, Jan Bobolz, Denis Pascal Diemert, and Fabian Eidens.
    “Updatable Anonymous Credentials and Applications to Incentive Systems.” In <i>Proceedings
    of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS
    ’19</i>. Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications
    Security - CCS ’19, 2019. <a href="https://doi.org/10.1145/3319535.3354223">https://doi.org/10.1145/3319535.3354223</a>.
  ieee: 'J. Blömer, J. Bobolz, D. P. Diemert, and F. Eidens, “Updatable Anonymous
    Credentials and Applications to Incentive Systems,” presented at the 26th ACM
    Conference on Computer and Communications Security, London, 2019, doi: <a href="https://doi.org/10.1145/3319535.3354223">10.1145/3319535.3354223</a>.'
  mla: Blömer, Johannes, et al. “Updatable Anonymous Credentials and Applications
    to Incentive Systems.” <i>Proceedings of the 2019 ACM SIGSAC Conference on Computer
    and Communications Security - CCS ’19</i>, 2019, doi:<a href="https://doi.org/10.1145/3319535.3354223">10.1145/3319535.3354223</a>.
  short: 'J. Blömer, J. Bobolz, D.P. Diemert, F. Eidens, in: Proceedings of the 2019
    ACM SIGSAC Conference on Computer and Communications Security - CCS ’19, 2019.'
conference:
  end_date: 2019-11-15
  location: London
  name: 26th ACM Conference on Computer and Communications Security
  start_date: 2019-11-11
date_created: 2019-10-18T08:09:44Z
date_updated: 2023-01-10T10:25:27Z
ddc:
- '006'
department:
- _id: '7'
- _id: '64'
doi: 10.1145/3319535.3354223
file:
- access_level: closed
  content_type: application/pdf
  creator: jbobolz
  date_created: 2019-10-18T08:07:49Z
  date_updated: 2019-10-18T08:07:49Z
  file_id: '13907'
  file_name: full_eprinted_v2.pdf
  file_size: 838949
  relation: main_file
file_date_updated: 2019-10-18T08:07:49Z
has_accepted_license: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2019/169.pdf
oa: '1'
project:
- _id: '1'
  name: SFB 901
- _id: '4'
  name: SFB 901 - Project Area C
- _id: '13'
  name: SFB 901 - Subproject C1
publication: Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications
  Security - CCS '19
series_title: Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications
  Security - CCS '19
status: public
title: Updatable Anonymous Credentials and Applications to Incentive Systems
type: conference
user_id: '25078'
year: '2019'
...
---
_id: '3265'
abstract:
- lang: eng
  text: "We present CLARC (Cryptographic Library for Anonymous Reputation and Credentials),
    an anonymous credentials system (ACS) combined with an anonymous reputation system.\r\n\r\nUsing
    CLARC, users can receive attribute-based credentials from issuers. They can efficiently
    prove that their credentials satisfy complex (access) policies in a privacy-preserving
    way. This implements anonymous access control with complex policies.\r\n\r\nFurthermore,
    CLARC is the first ACS that is combined with an anonymous reputation system where
    users can anonymously rate services. A user who gets access to a service via a
    credential, also anonymously receives a review token to rate the service. If a
    user creates more than a single rating, this can be detected by anyone, preventing
    users from spamming ratings to sway public opinion.\r\n\r\nTo evaluate feasibility
    of our construction, we present an open-source prototype implementation."
author:
- first_name: Kai
  full_name: Bemmann, Kai
  last_name: Bemmann
- first_name: Johannes
  full_name: Blömer, Johannes
  id: '23'
  last_name: Blömer
- first_name: Jan
  full_name: Bobolz, Jan
  id: '27207'
  last_name: Bobolz
- first_name: Henrik
  full_name: Bröcher, Henrik
  id: '41047'
  last_name: Bröcher
- first_name: Denis Pascal
  full_name: Diemert, Denis Pascal
  id: '44071'
  last_name: Diemert
- first_name: Fabian
  full_name: Eidens, Fabian
  id: '25078'
  last_name: Eidens
- first_name: Lukas
  full_name: Eilers, Lukas
  last_name: Eilers
- first_name: Jan Frederik
  full_name: Haltermann, Jan Frederik
  id: '44413'
  last_name: Haltermann
- first_name: Jakob
  full_name: Juhnke, Jakob
  id: '48090'
  last_name: Juhnke
- first_name: Burhan
  full_name: Otour, Burhan
  last_name: Otour
- first_name: Laurens Alexander
  full_name: Porzenheim, Laurens Alexander
  id: '47434'
  last_name: Porzenheim
- first_name: Simon
  full_name: Pukrop, Simon
  last_name: Pukrop
- first_name: Erik
  full_name: Schilling, Erik
  last_name: Schilling
- first_name: Michael
  full_name: Schlichtig, Michael
  id: '32312'
  last_name: Schlichtig
- first_name: Marcel
  full_name: Stienemeier, Marcel
  last_name: Stienemeier
citation:
  ama: 'Bemmann K, Blömer J, Bobolz J, et al. Fully-Featured Anonymous Credentials
    with Reputation System. In: <i>Proceedings of the 13th International Conference
    on Availability, Reliability and Security - ARES ’18</i>. New York, NY, USA: ACM.
    doi:<a href="https://doi.org/10.1145/3230833.3234517">10.1145/3230833.3234517</a>'
  apa: 'Bemmann, K., Blömer, J., Bobolz, J., Bröcher, H., Diemert, D. P., Eidens,
    F., … Stienemeier, M. (n.d.). Fully-Featured Anonymous Credentials with Reputation
    System. In <i>Proceedings of the 13th International Conference on Availability,
    Reliability and Security - ARES ’18</i>. New York, NY, USA: ACM. <a href="https://doi.org/10.1145/3230833.3234517">https://doi.org/10.1145/3230833.3234517</a>'
  bibtex: '@inproceedings{Bemmann_Blömer_Bobolz_Bröcher_Diemert_Eidens_Eilers_Haltermann_Juhnke_Otour_et
    al., place={New York, NY, USA}, title={Fully-Featured Anonymous Credentials with
    Reputation System}, DOI={<a href="https://doi.org/10.1145/3230833.3234517">10.1145/3230833.3234517</a>},
    booktitle={Proceedings of the 13th International Conference on Availability, Reliability
    and Security - ARES ’18}, publisher={ACM}, author={Bemmann, Kai and Blömer, Johannes
    and Bobolz, Jan and Bröcher, Henrik and Diemert, Denis Pascal and Eidens, Fabian
    and Eilers, Lukas and Haltermann, Jan Frederik and Juhnke, Jakob and Otour, Burhan
    and et al.} }'
  chicago: 'Bemmann, Kai, Johannes Blömer, Jan Bobolz, Henrik Bröcher, Denis Pascal
    Diemert, Fabian Eidens, Lukas Eilers, et al. “Fully-Featured Anonymous Credentials
    with Reputation System.” In <i>Proceedings of the 13th International Conference
    on Availability, Reliability and Security - ARES ’18</i>. New York, NY, USA: ACM,
    n.d. <a href="https://doi.org/10.1145/3230833.3234517">https://doi.org/10.1145/3230833.3234517</a>.'
  ieee: K. Bemmann <i>et al.</i>, “Fully-Featured Anonymous Credentials with Reputation
    System,” in <i>Proceedings of the 13th International Conference on Availability,
    Reliability and Security - ARES ’18</i>, Hamburg, Germany.
  mla: Bemmann, Kai, et al. “Fully-Featured Anonymous Credentials with Reputation
    System.” <i>Proceedings of the 13th International Conference on Availability,
    Reliability and Security - ARES ’18</i>, ACM, doi:<a href="https://doi.org/10.1145/3230833.3234517">10.1145/3230833.3234517</a>.
  short: 'K. Bemmann, J. Blömer, J. Bobolz, H. Bröcher, D.P. Diemert, F. Eidens, L.
    Eilers, J.F. Haltermann, J. Juhnke, B. Otour, L.A. Porzenheim, S. Pukrop, E. Schilling,
    M. Schlichtig, M. Stienemeier, in: Proceedings of the 13th International Conference
    on Availability, Reliability and Security - ARES ’18, ACM, New York, NY, USA,
    n.d.'
conference:
  end_date: 2018-08-30
  location: Hamburg, Germany
  name: ARES 2018 - SECPID
  start_date: 2018-08-27
date_created: 2018-06-14T11:19:29Z
date_updated: 2022-01-06T06:59:07Z
ddc:
- '000'
department:
- _id: '64'
doi: 10.1145/3230833.3234517
file:
- access_level: closed
  content_type: application/pdf
  creator: feidens
  date_created: 2018-11-08T10:17:39Z
  date_updated: 2018-11-08T10:17:39Z
  file_id: '5428'
  file_name: react_acs.pdf
  file_size: 920843
  relation: main_file
file_date_updated: 2018-11-08T10:17:39Z
has_accepted_license: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2018/835
oa: '1'
place: New York, NY, USA
project:
- _id: '1'
  name: SFB 901
- _id: '4'
  name: SFB 901 - Project Area C
- _id: '13'
  name: SFB 901 - Subproject C1
- _id: '44'
  name: KogniHome - die mitdenkende Wohnung
publication: Proceedings of the 13th International Conference on Availability, Reliability
  and Security - ARES '18
publication_identifier:
  isbn:
  - 978-1-4503-6448-5
publication_status: accepted
publisher: ACM
quality_controlled: '1'
related_material:
  link:
  - relation: software
    url: https://github.com/upbcuk
status: public
title: Fully-Featured Anonymous Credentials with Reputation System
type: conference
user_id: '25078'
year: '2018'
...