How can we continue to have control over our own data in the digital world? Fraunhofer AISEC’s solution is informational selfdetermination with selective disclosure. To make that happen it develops the C library libbbs as part of the TRUSTED consortium – publicly accessible as open source on GitHub.
Fraunhofer AISEC, a research partner in the EU-funded TRUSTED project, is developing and maintaining the C library libbbs, available as open-source. Implementing the IRTF draft, which is a work-in-progress research document by the Internet Research Task Force and possible future BBS standard, libbbs is a core building block for trusted data sharing.
Selective Disclosure Explained as an Everyday Problem
When you show someone your passport or a library card, you often reveal more than necessary. You might only want to prove that you are over 18, but the document also exposes your full name, address, and date of birth. In the physical world you could redact information or hand over a censored copy.
Digital documents make this problem even more complex. To verify a digital signature, the entire document must be checked – which again discloses everything.
Within the TRUSTED consortium, Fraunhofer AISEC addresses this challenge with selective disclosure, powered by zero-knowledge arguments of knowledge. Signature schemes such as BBS (the abbreviation comes from the authors of the original academic work: Boneh, Boyen, and Shacham) allow the creation of convincing cryptographic arguments. These arguments prove that you possess a valid document with near arbitrary properties such as “The document says age=35”, but theoretically even “The document has an age of at least 18”. And what makes these arguments zero-knowledge? The fact that these are the only revealed facts – everything else stays secret.
C library libbbs: Available as Open Source on GitHub
The C library libbbs:
- Implements the IRTF draft and possible future BBS standard
- Contributes to the specification of the emerging standard by providing feedback and testing limits with regards to speed, fitness for a variety of purposes (such as on embedded devices), more space efficient cryptographic proofs, future extensibility, and much more
Access the C library libbbs here: https://github.com/Fraunhofer-AISEC/libbbs
More in-depth information is provided here concerning:
From Selective Disclosure to Post-Quantum Security
Work on the C library libbbs is embedded in a broader research agenda at Fraunhofer AISEC within TRUSTED. Planned directions for future research include:
- Post-quantum resistant alternatives to BBS
- Further speed improvements
- New zero-knowledge proofs
- Hardware-bound secret keys
About Fraunhofer AISEC and Its Role in TRUSTED
Fraunhofer AISEC focuses on translating excellent IT security research into application-oriented solutions. Within TRUSTED, Fraunhofer AISEC contributes in three main areas:
- Analysis of existing Self-Sovereign Identity (SSI) technologies and their applicability in data spaces.
- Adaptation of identity management tools to existing data space specifications.
- Development of privacy-enhancing technologies and cryptographic techniques to enable cross-organizational data use for machine learning.
Through libbbs and related research, Fraunhofer AISEC strengthens TRUSTED’s role as a key enabler of secure and privacy-preserving data sharing in Europe’s emerging data spaces.
TrustED has received funding from the European Union’s Horizon Europe Research and Innovation Programme under grant agreementNo. 101168467