January 18, 2017

Threshold signatures for Bitcoin wallets are finally here

Today we are pleased to release our paper presenting a new ECDSA threshold signature scheme that is particularly well-suited for securing Bitcoin wallets. We teamed up with cryptographer Rosario Gennaro to build this scheme. Threshold signatures can be thought of as “stealth multi-signatures.” [Read more…]

Consensus in Bitcoin: One system, many models

At a technical level, the Bitcoin protocol is a clever solution to the consensus problem in computer science. The idea of consensus is very general — a number of participants together execute a computation to come to agreement about the state of the world, or a subset of it that they’re interested in.

Because of this generality, there are different methods for analyzing and proving things about such consensus protocols, coming from different areas of applied math and computer science. These methods use different languages and terminology and embody different assumptions and views. As a result, they’re not always consistent with each other. This is a recipe for confusion; often people disagree because they’ve implicitly assumed one world-view or another. In this post I’ll explain the two main sets of models that are used to analyze the security of consensus in Bitcoin.

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Expert Panel Report: A New Governance Model for Communications Security?

Today, the vulnerable state of electronic communications security dominates headlines across the globe, while surveillance, money and power increasingly permeate the ‘cybersecurity’ policy arena. With the stakes so high, how should communications security be regulated? Deirdre Mulligan (UC Berkeley), Ashkan Soltani (independent, Washington Post), Ian Brown (Oxford) and Michel van Eeten (TU Delft) weighed in on this proposition at an expert panel on my doctoral project at the Amsterdam Information Influx conference. [Read more…]