Subject: Re: [bitcoin-dev] Unlimited covenants, was Re: CHECKSIGFROMSTACK/{Verify} BIP for Bitcoin

From: "Russell O'Connor" <[email-masked]>
Date: Sun, 4 Jul 2021 22:10:17 -0400

On Sun, Jul 4, 2021 at 9:02 PM Russell O'Connor <[email-masked]>
wrote:

> Bear in mind that when people are talking about enabling covenants, we are
> talking about whether OP_CAT should be allowed or not.
>
> That said, recursive covenants, the type that are most worrying, seems to
> require some kind of OP_TWEAK operation, and I haven't yet seen any
> evidence that this can be simulated with CHECKSIG(FROMSTACK).  So maybe we
> should leave such worries for the OP_TWEAK operation.
>

Upon further thought, you can probably make recursive covenants even with a
fixed scritpubkey by sneaking the state into a few bits of the UTXO's
amount.  Or if you try really hard, you may be able to stash your state
into a sibling output that is accessed via the txid embedded in the
prevoutpoint.