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April 30, 2015

coinscrum-presents-Metadata in the Blockchain: The OP_RETURN Explosion


Metadata in the Blockchain: The OP_RETURN Explosion
Presented Gideon Greenspan, Founder and CEO, Coin Sciences Ltd (
Just over a year ago, Bitcoin Core introduced an official mechanism for embedding arbitrary metadata in transactions, called OP_RETURN. This transformed bitcoin into a low-level protocol on which many decentralised applications can be built. Since then, OP_RETURN metadata has been growing exponentially, with uses including document notarisation, colored coins, messaging and permanent data storage .In this talk well begin by reviewing the history of metadata in the blockchain and its underlying economic rationale. We’ll then consider what types of applications it is suitable for, and look at some which are already growing rapidly in use.We’ll finish by presenting CoinSpark ( ), an open source protocol for enhancing bitcoin transactions which makes extensive use of OP_RETURNs. Since OP_RETURNs are currently limited to 40 bytes, well discuss some of the technical tricks that CoinSpark uses to maximize the value of those few precious bytes.
18:30hrs – Doors open, 19:00hrs – Presentation begins, 20:00hrs – Networking / beer, 21:00hrs – Ends

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Paul Gordon
Following a 20+ year career in financial markets, Paul first became interested in Bitcoin in 2011 and helped to establish one of the world's first Bitcoin meetup groups, Coinscrum, in 2012 since when he has grown the community to over 6,500 members, hosting over 250 events and introducing many of the leading projects and thought leaders in the industry.  Paul currently produces the weekly Coinscrum Markets video podcast series and is an active investor and advisor to a number of crypto and blockchain related projects.

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