Session Date/Time: 31 Mar 2023 00:30

cfrg

Summary

The CFRG meeting covered a range of topics including updates on existing drafts, proposals for new work, and discussions on security considerations for cryptographic primitives. Key discussions revolved around authoring advice for cryptographic specifications, security models for key winding schemes, and verifiable distributed aggregation functions. The meeting also explored updates on the video signature scheme, properties of attribute-based encryption, and partially blind RSA signatures.

Key Discussion Points

Authoring Advice for Cryptographic Specifications: A proposal for a new draft to provide comprehensive advice for authors of cryptographic specifications was discussed. The goal is to improve the quality, minimize ambiguity, and ensure consistent implementations.
Security Analysis of Key Winding Schemes: An analysis of the security proofs for variations of key winding signature schemes was presented, focusing on different security models and implementation choices.
Verifiable Distributed Aggregation Functions (VDAF): Security definitions for VDAF were discussed, particularly privacy and robustness. Updates and impact on the existing draft were presented.
Video Signature Scheme Updates: Updates on the video signature scheme draft were shared including modifications related to random scalar computation and the inclusion of test vectors.
Properties of Attribute-Based Encryption (ABE): Updates on the ABE draft were discussed with focus on consistency, new properties and functional examples.
Partially Blind RSA Signatures: Presentation and discussion of partially blind RSA signatures based on a new draft, motivated by privacy pass and other applications.
Plasma: A Framework for Private and Lightweight Statistics: Presentation and discussion of Plasma including the implementation of Verifiable Point Functions and comparison to Popular.
Hybrid Key Encapsulation Mechanisms (KEMs): A proposal to standardize a robust combine for hybrid KEMs was presented, highlighting the need for strong constructions in various protocols.
HpKE Extensions: The question of extending the HPKE draft with Hmac and a Cbc was opened up for the Cfrg for consideration.

Decisions and Action Items

Authoring Advice Draft: Nick Sullivan will proceed with creating an individual draft on authoring advice for cryptographic specifications. The group showed strong support and volunteered to contribute and review.
Video Signature Scheme: The group needs feedback on moving test cases to a separate document, defining map scale methods and to compress point encoding methods.
Partially Blind RSA Signatures: Present the document for adoption and bring to the list for production.
Hybrid KEM Combine: Further discussion on the mailing list regarding the use of SHA-3 versus SHA-2 and adoption of the document.

Next Steps

Nick Sullivan will circulate an individual draft on authoring advice for cryptographic specifications.
Participants should provide feedback on the video signature scheme draft.
The proposal for standardized Hybrid KEM will discussed on the mailing list.
Scott needs to post to the list regarding an crypto graphical weakness in the Partially Blind RSA signatures.