Motivation

SnarkVM process stores the inclusion prover and verifier in static location in memory. It is initialized via load_bytes method defined by the impl_remote! macro in the parameters and lazily loaded into a static location the first time the inclusion_proving_key is called. If trying to build a transaction offline using a SnarkVM process running in userspace, this will first check if the inclusion prover is located at a specific location on disk, otherwise it will attempt to download it from the internet.

As a matter of security, wasm runtimes run in a sandboxed environment and generally do not have access to their host machine's file system directly. Thus, the normal approach of checking the local filesystem is not available, and the sole option for initializing the inclusion prover is download it.

If desiring to build a transaction on an offline machine that is using a wasm binary, the inclusion prover is unable to be loaded and offline transaction building will fail. This effectively means offline transaction creation is not available in a javascript environment. Many offline wallets, custodians, and other developers generally desire to write their applications in node.js and thus are currently blocked from doing so.

This PR introduces an option to insert the inclusion prover bytes from an external source, and verify that the checksum and byte buffer length match the expected values for the inclusion prover, allowing safe external insertion of the inclusion prover.

Test Plan

Add tests that ensure

• Bytes that do not match the expected inclusion prover bytes do not pass.
• The inclusion prover is successfully loaded from external sources.
• All functionality surrounding the inclusion prover that exists when the wasm flag is not present remains unaffected.

Steps Before Marking PR as Ready for Review

• Write described tests.
• Code & style cleanup.
• Rebase onto the staging branch (this was branched from v3.8.0 tag in order to provide the SDK the ability to test offline transaction building against the latest stable mainnet tag)