Training wheels

[Mirko-von-Leipzig]

We want to (short term) loosen miden's privacy guarantees while we are still actively developing in a centralized fashion. Effectively, miden would have privacy only in the network sense and not from the node operator.

Private transactions will include the transaction data when submitting to the node operator. This data will not appear on-chain (same as it is now), but would be kept separately by the node.

This would act as training wheels, and the intention is to drop this sometime before decentralization.

There are some benefits:

• less regulatory issues
• (private) account recovery
• better debugging and support
• trivial full chain history and therefore recovery from some critical failure

and some downsides:

• more work for the node - tx data must be verified, probably by re-execution, negating (some) of the benefits of private transactions
• less complete privacy

ito implementation, it makes sense to store this data completely separately from the current database. This would minimize any actual node IO with the data beyond writing it.

This will of course require changes to RPC and the client.

[bobbinth]

One of the other main benefits is that we get to "double-check" the proofs and so any potential soundness bugs in the proving system would not cause catastrophic failures.