First #SmartCustody Workshop: Simple Cold Storage & Self-Custody

First Workshop: Simple Cold Storage & Self-Custody

Our first #SmartCustody workshop will be on Tue, January 29, 2019, 10:00 AM – 4:00 PM PST, at 554 San Antonio Road, Palo Alto, CA 94040-1217, Map.

You can signup for the Workshop on EventBrite.


This is the first of three different #SmartCustody workshops. This workshop is designed for individual holders of digital assets, in particular cryptocurrency traders and those high net-worth individuals who are already familiar & working with digital assets, but are seeking to learn best practices for protecting themselves and their business from theft, fraud, or loss.

  • Are you considering all possible threats to your digital assets?
  • Do you have comprehensive procedures to assess your risk profile?
  • How does your system stack up against others in industry?

Future workshops will be focused on holders of digital assets that have fiduciary responsibility to others, such as small investment funds & family firms, or those who are required to use third-party qualified custodians for management of digital assets due to the amount of funds held.

These #SmartCustody workshops are a project of Blockchain Commons, which supports blockchain infrastructure, internet security & cryptographic research.

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Project Proposal: New Social Social Key Recovery Approach

Project Proposal: New Social Social Key Recovery Approach

The goal of social key recovery is for the user to specify groups of individuals that together possess the ability to recover the root secret of a wallet. A good social key recovery protocol should not just reflect what cryptographic primitives happen to be available for use, but rather instead should be designed to correspond with the structure of trust in the user’s social network, while balancing the technical tradeoffs involved under the hood.

The most popular social key recovery algorithm, Shamir Secret Sharing is considered information-theoretically secure. That is, any combination of shares less than the necessary threshold convey absolutely no information about the secret. However, all secrets have equal weight and once a sufficient threshold is achieved the secret can be reconstructed. In social contexts this can cause a number of problems in common real-world scenarios. In addition, Shamir Secret Sharing has a history of being naively implemented including a number of serious vulnerabilities.

To quote Bitcoin Core Developer Greg Maxwell:

I think Shamir Secret Sharing (and a number of other things, RNGs for example), suffer from a property where they are just complex enough that people are excited to implement them often for little good reason, and then they are complex enough (or have few enough reasons to invest significant time) they implement them poorly.”

Ideally an implementation of social key recovery should balancing numerous competing goals:

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