They could've created a federated SGX-based model on top of any of the existing cryptocurrencies. The only reason for them to invent a new one is making $$$.
How so? When I consider how to build it on top of an existing smart contact platform you'd have to have a whole extra, nonstandard layer for key rotation and you'd miss out on privacy guarentees. If we assume their goal of privacy and sub 10s finality I can't see how they could have done it on an existing cryptocurrency.
What they've done is essentially take Monero as a base, remove mining and use Stellar Consensus then solve any new privacy issues that arise.
What they've done is essentially take Monero as a base, remove mining and use Stellar Consensus then solve any new privacy issues that arise.