To give you an example there is this application called https://bisq.network/ that uses double-sided collateral in contracts to trade fiat currencies. There might be the potential to link this up with SSL, too. I've seen this application that can provide proofs that a page was in your browser https://tlsnotary.org/. Use that to prove a bank transfer happened on an SSL page and you've got yourself a dex that can work trustless with oracles.
The technical problems with that are much less important than the legal problems.
It's likely that the IRS will maul users (unless they report every transaction as a tax event!), and the bank may refuse transactions. Users may even ask the bank to refuse transactions, and then your collateral isn't really a collateral.
Isn't that a contradiction in terms?
It's kind of like how SMS messages worked fine until “if I can read an SMS sent to your number I can withdraw from your account” became part of the threat model.
Don’t these DeFi projects have an even worse track record than the centralised exchanges?
I will say one thing about Mark Cuban - he's deep into the DeFi/dApp world and seems to actually know his stuff on a deep level.
Of course, the code running a DEX is fully auditable by anyone, unlike the code powering a centralized exchange.
1. Bugs 2. Social engineering
In a decentralised exchange you increase your vulnerability to 1 trying to get rid of 2 on the exchange side, and I'm unsure you can offer the features that the bulk of traders want on a decentralised exchange. Actually, I'm sure (enough to bet 50 $ on it if there is a way to properly specify it) that the most important thing cannot be offered by decentralised exchanges: cashing out to pay your taxes in fiat.
So the theoretical "bug bounty" is way lower on a decentralized exchange. Decentralized exchanges have a smaller attack surface than centralized exchanges, and be publicly & professionally audited. That's why they don't usually get hacked.
- micropayment channels -- send money a piece at a time
- cross chain contracts -- bind simultaneous release of funds to a shared secret
- lightning channels -- cross-blockchain stateful commitments
- reputation -- not great but can still work
The order book is another part that can be decentralized. It's a little harder to do this due to the need for high speed communication but I believe its possible. Newer blockchains like Solana have different consensus algorithms that allow for a 'global clock' to be created with minimal bottlenecks. It wouldn't be as fast as everything sitting on a server but its performance would be adequate for traders, IMO.
Bonus section: dark pools could be created with SGX or MPC protocols. There are some popular decentralized exchanges at the moment. But IMO they will need more features that traders are familiar with to be competitive (there's more than just currency pairs and limit orders tbh.)
Also: big shout out to https://www.projectserum.com/