Commitments

Here we illustrate the commitment scheme used to create authenticated commitments to the plaintext in scenarios where a general-purpose Notary is used. (Note that this scheme is not used when the Prover proves directly to the Verifier)

A naive approach of extending the Encryption and Decryption steps to also compute a commitment (e.g. BLAKE3 hash) using MPC is too resource-intensive, prompting us to provide a more lightweight commitment scheme.

The high-level idea is that the Prover creates a commitment to the active plaintext encoding from the MPC protocol used for Encryption and Decryption.

We also hide the amount of commitments (to preserve Prover privacy) by having the Prover commit to the Merkle tree of commitments.