Wasabi Research Club # 18 - Protocol KVAC
Channel: Wasabi Wallet
Date: 2020-05-05

Our researchers discuss cryptographic primitives. They discuss the commitment schemes, digital signatures, and knowledge proofs used in their Wabi-Sabi protocol. They also explain the protocol KVAC, which is a three-move Sigma protocol commonly used in zero knowledge proof systems. They discuss the high-level description of the protocol, the transfer of values and serial numbers, and how the protocol ensures privacy and security. The speaker also explains the process of registering a shin and signing a face in the Protocol KVAC, as well as the importance of choosing valid points on the curve. Lastly, they discuss the process of breaking down an input into multiple inputs and submitting commitments for each value, ensuring validity and preventing manipulation.

Topic: Protocol KVAC

Wasabi Research Club playlist:
https://www.youtube.com/playlist?list=PLPwc75tPMdsgTYlu9dJZlosCm0s7WmIpF
Join The Wasabikas Highlights playlist: https://youtube.com/playlist?list=PLPwc75tPMdsjpqK1YHYYG5b55M6Y--6Qd
Join The Wasabikas full episodes playlist: https://youtube.com/playlist?list=PLPwc75tPMdsixsuhwau82Q0IfxECo0z_E
Website: https://WasabiWallet.io
Blog: https://blog.WasabiWallet.io
Documentation: https://docs.WasabiWallet.io
GitHub: https://github.com/zkSNACKs/WalletWasabi
Podcast: https://anchor.fm/Wasabikas
YouTube: https://youtube.com/c/WasabiWallet

00:00 Overview of WabiSabi. / Fixing the mixing protocol.

02:11 Review by Istáv/Yuval. / Commitment schemes and zero-knowledge protocols (Damgard & Nielsen, 2011)

06:58 Hash-then-Message-Authentication-Code (HMAC) / Algebraic MAC.

13:40 Signal Private Group System (Chase, Perin, Zaverucha, 2019) / Sigma-protocols (Damgard, 2010)

18:47 Zero-Knowledge Proofs.

23:52 Schnorr-identification protocol as an interactive protocol. / Fiat-Shamir heuristic. / Properties: Correctness, soundness, zero-knowledge.

30:33 WabiSabi protocol. / Homomorphism. / Pedersen commitments.

38:26 Output Registration. / Blind Signature Scheme with attributes.

46:06 Cryptographic details. / Hash-and-pray

56:02 Input Registration. / Range-proof. / Witness-hiding.

01:04:22 Cryptographic details of output Registration. / Show protocol. / Issuance parameters.

01:12:07 Over-spending prevention.

01:19:58 Conclusion. / Algebraic MAcs and Keyed-Verification Anonymous Credentials. (Chase, Meiklejohn & Zaverucha, 2013)

01:23:10 Where is homomorphism of commitments used?

01:25:42 How hard are the computations for the coordinator. / lightweight.money