Hello bitcoin-devs,

Below is a link to a BIP Draft for a new opcode, OP_CHECKOUTPUTSHASHVERIFY.
This opcode enables an easy-to-use trustless congestion control techniques
via a rudimentary, limited form of covenant which does not bear the same
technical and social risks of prior covenant designs.

Congestion control allows Bitcoin users to confirm payments to many users
in a single transaction without creating the UTXO on-chain until a later
time. This therefore improves the throughput of confirmed payments, at the
expense of latency on spendability and increased average block space
utilization. The BIP covers this use case in detail, and a few other use
cases lightly.

The BIP draft is here:
https://github.com/JeremyRubin/bips/blob/op-checkoutputshashverify/bip-coshv.mediawiki

The BIP proposes to deploy the change simultaneously with Taproot as an
OPSUCCESS, but it could be deployed separately if needed.

An initial reference implementation of the consensus changes and  tests
which demonstrate how to use it for basic congestion control is available
at https://github.com/JeremyRubin/bitcoin/tree/congestion-control.  The
changes are about 74 lines of code on top of sipa's Taproot reference
implementation.

Best regards,

Jeremy Rubin