Ability to support anonymonity for orders

[boolafish]

Description

As a trader, I want to make sure the order is anonymous on plasma chain,
So that other traders cannot learn unnecessary information from my order.

sub story of #53

Note

I would say just make this story using zk-snark. We can add story to investigate other possible solutions if there's concern on zk-snark.
related to #68

Successful Criteria

• Document the proof using zk-snark

[boolafish]

[previously commented in wrong issue lol...]

A note from the meeting with Clearpool. Basically operator should not be able to see the orders as well. If we want to do so, and assumes OmieseGo would be the one running operator, it means OmiseGO would need to get some regulation certificate (?) to be able to run, also, it would only be able to provide service to limited countries that such certificate allows.

[boolafish]

(slack) Some high level note
pepesza [21 hours ago]
We should go SNARKs route because:

1. SGX is just crazy - it's unknown unknowns.
2. The only possible way of doing STARKs today is buying stack from Starkware. I don't believe we have a mandate to spend community money on proprietary stack.
3. SNARKs, while it would require some programming usually reserved to implementers of cryptographic stacks, are really doable. In the worst case we will pay someone in the field to help us review/audit the code. The rest of the implementation is clearly in our reach

[boolafish]

As we decide to focus on snark and most of the discussion sits in #87, would close this one and just use that one further on.