Threshold cryptography enables a group of nodes to jointly perform cryptographic computations using a key that is shared among the nodes. In most settings, for n nodes and a threshold t, any subgroup of at least t nodes will be able to perform the intended computation whereas any subgroup of less than t nodes will not.

After threshold cryptography had been primarily a field of academic research for many years, it recently gained traction in practice due to the advent of blockchains and decentralized ledger technologies more generally, whose settings are well aligned with the distributed nature of threshold cryptosystems. Nevertheless, there is still a significant gap between the academic results and the implementation of threshold cryptography for mission-critical applications.

In this talk, I will provide a gentle introduction to the topic and explain how threshold cryptography can be deployed in a highly reliable way in a blockchain network. I will also describe several use cases that make use of threshold cryptography to bridge between different blockchain networks.