Configurable Asset Privacy and Proof-Carrying Disclosures with Ben Fisch | a16z crypto research

TL;DR

The Cap protocol allows for configurable asset privacy on the Ethereum application layer, providing users with more options for privacy control and risk management.

Transcript

welcome everybody to the seminar for the week we're really glad to have Ben Fish who uh just finished his PhD at Stanford last year working with Dan uh and now he's just started as a professor at Yale he's the co-founder and CEO of espresso Ben's known for his work on uh vdfs on uh proofs of uh groups of replication or catalytic proofs of space his... Read More

Key Insights

• 🖕 Cap offers a middle ground between transparent blockchains and fully anonymous protocols, providing users with greater privacy control.
• 👻 The protocol addresses the collateral damage caused by illicit transactions in mixing services by allowing issuers to define custom privacy policies.
• 👻 Multiple allow lists can be supported, enabling more nuanced regulation and reducing the risk of broad sanctions.
• 👻 Proof Carrying Disclosures allow for privacy and compliance in shielded pools, ensuring that users can demonstrate the legitimacy of their funds without compromising privacy.
• 😒 The challenges of designing privacy protocols involve balancing positive use and discouraging misuse, as well as the need for regulatory frameworks that consider the nuances of privacy technologies.

Questions & Answers

Q: What is the motivation behind introducing the configurable asset privacy protocol?

The motivation is to provide users with more options in terms of privacy control and risk management. The current approach to privacy in blockchain is limited to either complete transparency or full anonymity, and Cap aims to offer a middle ground.

Q: How does Cap address the collateral damage caused by illicit transactions in mixing services?

Cap allows issuers to create custom privacy policies, giving them the ability to restrict how their assets are being used. This can prevent situations where an issuer has to ban the entire flow of assets due to illegitimate use, causing collateral damage to innocent users.

Q: Can multiple allow lists be supported by the Cap protocol?

Yes, the Cap protocol supports multiple allow lists, allowing for more fine-grained control over asset membership and mitigating the risk of sanctions on entire protocols due to the actions of a few users.

Q: How does Proof Carrying Disclosures work in the context of shielded pools?

Proof Carrying Disclosures enable users to carry attestations of allow list membership through the private transaction graph. This allows users to demonstrate that their funds originated from an allowed list without revealing the actual membership on-chain, ensuring privacy and compliance simultaneously.

Summary & Key Takeaways

• The Cap protocol, developed by the Espresso team, offers a new approach to privacy in blockchain by providing configurable asset privacy options.

• The protocol allows issuers of digital assets to define custom privacy policies, balancing risk management and user privacy.

• The current version of Cap focuses on viewing keys and freezing keys, offering increased flexibility and control over asset privacy.