Those who have been in crypto long enough remember the not-so-good-ol’ days when an air-gapped machine was the only way to store private keys securely. Thankfully, the wallet space has come a long way from that era. But we still live in a world where the seed phrase is the single atomic point of failure. Enter threshold signatures schemes (TSS), a multi-party computation (MPC) where different parties generate a key and are all required to create a valid signature.  We’re joined by Omer Shlomovits and Ouriel Ohayon, Co-founders of ZenGo. Their product is a ‘keyless’ crypto wallet, which means users never need to generate or store a key which gives them access to their funds. Keys are created with an MPC, where both ZenGo and the user are required to sign a transaction. TTS opens up exciting new possibilities like social recovery, user permissions for teams, and inheritance planning schemes. The important distinction between ZenGo and existing multi-signature wallets is that they achieve this using only cryptography, and do not rely on on-chain elements like smart contracts or op_scriptSig in Bitcoin. Topics covered in this episode: - Omer and Ouriel’s respective backgrounds in academia and online consumer-facing products - What lead them to want to build yet another crypto wallet - The state of custody in the crypto wallet ecosystem and the challenge which remain unaddressed - A quick refresh on cryptographic primitives and multi-party computations (MPC) - The building blocks of cryptographic signatures and threshold signature schemes (TSS) - How TSS is different from Bitcoin multi-sig and smart contract multi-sig - TSS in ECDSA vs. Schnorr signatures - Applications and use cases for TSS - ZenGo’s on-boarding, restore process and use of biometrics - The future of wallet interoperability in a world of proprietary cryptographic schemes Episode links:  - [ZenGo: Bitcoin & Cryptocurrency Wallet](https://zengo.com) - [‎ZenGo: Bitcoin & Crypto Wallet on the App Store](https://Zengo.com/enjoy) - [Threshold Signatures Explained](https://www.binance.vision/security/threshold-signatures-explained) - [ShareLock: Mixing for Cryptocurrencies from Multiparty ECDSA](https://eprint.iacr.org/2019/563.pdf) - [KZen Networks on GitHub](https://github.com/KZen-networks) - [Zengo Research](https://zengo.com/research/) - [KZen Research Telegram Group](https://t.me/kzen_research) - [Tel Aviv Blockchain Week Recap with Anna Rose of the Zero Knowledge Podcast](https://www.youtube.com/watch?v=ccywXWTSFKM) Sponsors:  - Vaultoro: Trade gold to Bitcoin instantly and securely starting at just 1mg - http://vaultoro.com - Trail of Bits: Trust the team at the forefront of blockchain security research - https://trailofbits.com This episode is hosted by Sebastien Couture & Brian Fabian Crain. Show notes and listening options: [epicenter.tv/306](https://epicenter.tv/306)

We’re pleased to be joined by the legendary cryptographer and computer scientist, David Chaum. From his early beginnings at Berkley, David pioneered many of the cryptographic techniques used in secure systems and cryptocurrencies today. Blind signatures, which are used in zero-knowledge proofs, and mix networks, used in Tor heavily rely on his work. At the dawn of the Internet, David founded DigiCash, what many believe to be a direct ancestor of Bitcoin. Today, David continues to pursue his mission to bring data privacy to all as his most recent project, Elixxir, aims to create a truly private messaging and payment app with a mass-market appeal. Topics covered in this episode: - David’s background as a Ph.D. student at Berkeley and his thesis entitled “Computer Systems Established, Maintained, and Trusted by Mutually Suspicious Groups” - What drove him to work on cryptography and privacy systems - His relationship to the early cypherpunk movement - David’s contribution to cryptography primitives such as blind signatures, undeniable signatures, group signatures and mixers - The story of DigiCash and how the company was founded - The idea behind Cyberbucks and why the company ultimately went bankrupt - Cryptocurrency adoption as a chicken-and-egg problem - David’s personal views and practices with regards to online privacy - His thoughts on the blockchain space today and his views on the future of the industry - His current project, Elixxir, a messaging and payment app which protects users’ data and metadata Episode links:  - [David Chaum’s website](https://chaum.com) - [DigiCash](https://www.investopedia.com/terms/d/digicash.asp) - [lists.cpunks.org Mailing Lists](https://lists.cpunks.org/mailman/listinfo) - [DigiCash - Wikipedia](https://en.wikipedia.org/wiki/DigiCash) - [Blind Signatures for Untraceable Payments](https://www.chaum.com/publications/Chaum-blind-signatures.PDF) - [DigiCash announcement article from 1994](https://www.chaum.com/ecash/articles/1994/05-27-94%20-%20World_s%20first%20electronic%20cash%20payment%20over%20computer%20networks.pdf) - [Project Page: Multiparty Computation](https://www.chaum.com/spymasters/) - [Security without Identification](https://www.chaum.com/publications/Security_Wthout_Identification.html) - [Elixxir - Home](https://elixxir.io/) - [Elixxir - Real Cryptography, Real Time: Precomputations in Elixxir](https://elixxir.io/blog/real-cryptography-real-time) - [Elixxir - Why Mark Zuckerberg wants no privacy, why he wrote his letter,  and why it won’t help him](https://elixxir.io/blog/why-zuckerberg-wants-no-privacy) - [Elixxir - Point of Departure](https://elixxir.io/blog/point-of-departure) - [cMix white paper](https://drive.google.com/file/d/1B1jv03qc8E1kx0kvGFx4blzwXrQepMyy/view) Sponsors:  - Vaultoro: Trade gold to Bitcoin instantly and securely starting at just 1mg - http://vaultoro.com - Trail of Bits: Trust the team at the forefront of blockchain security research - https://trailofbits.com This episode is hosted by Sebastien Couture & Friederike Ernst. Show notes and listening options: [epicenter.tv/304](https://epicenter.tv/304)