Editing Work (section)

== What I learned ==

Coinbend was like my master class in designing smart contracts. It taught me all about trust and how complex distributed systems are to secure. In many ways the techniques I was learning (and sometimes inventing) have become commonplace. For instance: my conception of ‘green addresses’ described in the white paper was something I invented to reduce leverage in multi-sig deposits prior to opening a micro-payment channel and now forms the basis for some of the most high-security key-management systems in the blockchain space (like keys.casa).

The Coinbend project taught me many difficult attack scenarios in distributed systems. I now notice many problems with using ‘daps’ (most often race conditions.) I learned all about applied cryptography, too - even inventing my own techniques for creating a passive key recovery system (timechains.)

I had decentralized alt-coin trading working across blockchains at a time when Ethereum didn’t even exist yet and Lightning was barely a twinkle in anyone’s eyes. In fact, it was probably the first decentralized exchange at the time that was actually trustless.

I might have been the first person to implement cross-chain contracts, too. I’ve seen many people claim to have done this over the years but there’s several good reasons to believe why these claims are false:

# The updates that were made to the cross-chain contract specification were made in response to the questions I sent TierNolan in PMs on Bitcointalk about standard TXs, transaction mutability, and other issues with the contract. I was the first person to have these issues because I was the first person to use the contract beyond theory.
# The only good Bitcoin TX library for building complex contracts was the one maintained by Peter Todd. When I wrote the original (and necessary) conditional transaction Script code to execute a cross-chain contract the library had a bug that prevented success. So if I was the first person to experience this bug it also implies I was probably the first person to try implement the contract (at least in Python.)
# I was active for years on Bitcointalk and literally no one else had software to do a cross-chain contract at the time (on existing blockchains.) The first project that did was developed by Matt Bell (https://github.com/mappum) and it was called ‘Mercury Exchange’, but even before that was released I had already implemented and abandoned cross-chain contracts for technical reasons as I believed (and still do) that micropayment channels are superior. My original prototype cross-chain contract code is here: https://github.com/robertsdotpm/crosschain_contract (messy code.)

Fast forward to today and decentralized exchanges are some of the most popular trading systems around – offering superior security, UX, reduced fees, and even in some cases - speed!

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