When I first created my decentralized exchange I wrote a whitepaper that introduced several new concepts.
- Green addresses (a way to do blockchain key management with high security – https://keys.casa uses the same technique.)
- Crypto-asset trading with minimal trust and only standard transactions (using micro-payment channels)
- Time-locked refunds without nLockTime (using https://roberts.pm/timechain)
- Peer-to-peer networking (using https://github.com/StorjOld/pyp2p)
- A (broken) decentralized order book
You can read the original paper here: https://github.com/robertsdotpm/coinbend/blob/master/server/www/whitepaper.pdf