Simple Fast Withdrawals

Even with (or without) case of “single operator with the threshold of stake”, the system must have “propose, wait for the challenge and commit” process while submitting the checkpoint. And allow anyone to challenge the invalid transaction. There are two issues here though:

  1. The challenge period must be long enough. Mitigation would be - use smaller block time and longer checkpoint time (and use partial confirmations). Similar to Plasma checkpoint cost and block time
  2. Data availability. I think that is being discussed on Minimal Viable Plasma