Ben DiFrancesco: Umbra – Privacy Preserving Token Transfers #496
Channel: Epicenter Podcast
Date: 2023-05-19

Public transaction history in blockchains represents one of their key features which, alongside immutability, aim to provide an alternative to CeFi. However, this transparency comes at a price: privacy. As a result, different solutions have been proposed, that preserve privacy while maintaining all the other benefits of blockchain technology, but there currently isn't a one-size-fits-all answer to this problem. For example, zero knowledge proofs convey the validity of a transaction batch without sharing any other details, but the underlying arithmetic circuits are both complex as well as computational intensive. Umbra proposes a system that relies completely on elliptic curve cryptography, employing multiple private-public key pairs to achieve stealth payments.

We were joined by Ben DiFrancesco, founder & CEO of ScopeLift, to talk about Umbra's privacy preserving stealth token transfer system and if the need for privacy on blockchains outweighs any implicit UX frictions.

Topics discussed in this episode:
0:00 - Introduction
0:27 - Ben’s background
7:34 - Umbra's mission
10:04 - How Umbra works
17:21 - Non-interactive key distribution
19:40 - Potential solutions (& trade-offs) for Umbra's computational intensity
27:41 - Generating private-public key pairs by the Umbra smart contract
32:38 - User experience (UX) for senders and receivers
39:38 - Fee structure for deterring griefing attacks
43:05 - How Umbra works for ERC20 tokens & NFTs
47:30 - Privacy preserving withdrawals from stealth addresses
54:39 - Privacy vs. UX friction
59:29 - Smart wallets & account abstraction
1:02:43 - Prioritising privacy

Links mentioned in this episode: 
- Ben DiFrancesco on Twitter: bit.ly/4367m8Y
- Umbra on Twitter: bit.ly/3WgsAPv
- ScopeLift on Twitter: bit.ly/3BIGYq6

This episode is hosted by Friederike Ernst. Show notes and listening options: https://epicenter.tv/496