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

From: ZmnSCPxj <[email-masked]>
Date: Mon, 05 Jul 2021 02:39:08 +0000

Good morning Russell,

> 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.

Which is kind of the point of avoiding giving too much power, because people can be very clever and start doing unexpected things from what you think is already a limited subset.
"Give an inch and they will take a mile".

Still, as pointed out, altcoins already exist and are substantially worse, and altcoin implementations are all going to run on Turing machines anyway (which are powerful enough to offer Turing-machine functionality), so maybe this is not really giving too much power, people can already fork Bitcoin and add full EVM support on it.

Regards,
ZmnSCPxj