Auditable Attribute-Based Credentials Scheme and Its Application in Contact Tracing

Paper 2023/1060

Auditable Attribute-Based Credentials Scheme and Its Application in Contact Tracing

Pengfei Wang, Tokyo Institute of Technology
Xiangyu Su, Tokyo Institute of Technology
Mario Larangeira, Tokyo Institute of Technology, Input Output Global
Keisuke Tanaka, Tokyo Institute of Technology
Abstract

During the pandemic, the limited functionality of existing privacy-preserving contact tracing systems highlights the need for new designs. Wang et al. proposed an environmental-adaptive framework (CSS '21) but failed to formalize the security. The similarity between their framework and attribute-based credentials (ABC) inspires us to reconsider contact tracing from the perspective of ABC schemes. In such schemes, users can obtain credentials on attributes from issuers and prove the credentials anonymously (i.e., hiding sensitive information of both user and issuer). This work first extends ABC schemes with auditability, which enables designated auditing authorities to revoke the anonymity of particular issuers. For this purpose, we propose an ``auditable public key (APK)'' mechanism that extends the updatable public key by Fauzi et al. (AsiaCrypt '19). We provide formal security definitions regarding auditability and build our auditable ABC scheme by adding a DDH-based APK to Connolly et al.'s ABC construction (PKC '22). Note that the APK mechanism can be used as a plug-in for other cryptographic primitives and may be of independent interest. Finally, regarding contact tracing, we refine Wang et al.'s framework and present a formal treatment that includes security definitions and protocol construction. An implementation is provided to showcase the practicality of our design.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Published elsewhere. Minor revision. 22nd International Conference on Applied Cryptography and Network Security (ACNS '24)
Keywords
Attribute-Based CredentialsAuditable Public KeysContact Tracing
Contact author(s)
pengfei w @ outlook com
su x ab @ m titech ac jp
mario larangeira @ iohk io
keisuke @ is titech ac jp
History
2024-06-28: last of 5 revisions
2023-07-07: received
See all versions
Short URL
https://ia.cr/2023/1060
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2023/1060,
      author = {Pengfei Wang and Xiangyu Su and Mario Larangeira and Keisuke Tanaka},
      title = {Auditable Attribute-Based Credentials Scheme and Its Application in Contact Tracing},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/1060},
      year = {2023},
      url = {https://eprint.iacr.org/2023/1060}
}
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