Storage Mining System - proving storage for producing blocks

The Storage Mining System is the part of the Filecoin Protocol that deals with storing Client's data, producing proof artifacts that demonstrate correct storage behavior, and managing the work involved.

Storing data and producing proofs is a complex, highly optimizable process, with lots of tunable choices. Miners should explore the design space to arrive at something that (a) satisfies protocol and network-wide constraints, (b) satisfies clients' requests and expectations (as expressed in Deals), and (c) gives them the most cost-effective operation. This part of the Filecoin Spec primarily describes in detail what MUST and SHOULD happen here, and leaves ample room for various optimizations for implementers, miners, and users to make. In some parts, we describe algorithms that could be replaced by other, more optimized versions, but in those cases it is important that the protocol constraints are satisfied. The protocol constraints are spelled out in clear detail (an unclear, unmentioned constraint is a "spec error"). It is up to implementers who deviate from the algorithms presented here to ensure their modifications satisfy those constraints, especially those relating to protocol security.