Resilient custody of crypto-assets, and threshold multisignatures

Abstract

Ensuring safe custody of crypto-assets, while at the same time allowing a user to easily access and transfer them, is one of the biggest challenges of this nascent industry. This is even harder considering also the multiple technological implementations behind each crypto-asset. Here we present a survey of the various solutions for this custody problem, comparing advantages and disadvantages. Then we delve deeper into some interesting schemes based on secure multiparty computation, which give a blockchain-agnostic solution that balances security, safety, and transactional ease of use, and in particular, a protocol that enhances practicality by exploiting a party that may stay offline during the key generation.