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From: Jeremy Rubin <jeremy.l.rubin@gmail.com>
To: Rusty Russell <rusty@rustcorp.com.au>,
	 Bitcoin Protocol Discussion
	<bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] TXHASH + CHECKSIGFROMSTACKVERIFY in lieu of CTV and ANYPREVOUT
Date: Mon, 7 Feb 2022 20:34:30 -0800	[thread overview]
Message-ID: <CAD5xwhgP2_51Dvar0f1tsMrCXZ61W9-HnLgR45D-54Oc7-X1ag@mail.gmail.com> (raw)
In-Reply-To: <87leymuiu8.fsf@rustcorp.com.au>

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Rusty,

Note that this sort of design introduces recursive covenants similarly to
how I described above.

Whether that is an issue or not precluding this sort of design or not, I
defer to others.

Best,

Jeremy


On Mon, Feb 7, 2022 at 7:57 PM Rusty Russell via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Russell O'Connor via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
> writes:
> > Given the overlap in functionality between CTV and ANYPREVOUT, I think it
> > makes sense to decompose their operations into their constituent pieces
> and
> > reassemble their behaviour programmatically.  To this end, I'd like to
> > instead propose OP_TXHASH and OP_CHECKSIGFROMSTACKVERIFY.
> >
> > OP_TXHASH would pop a txhash flag from the stack and compute a (tagged)
> > txhash in accordance with that flag, and push the resulting hash onto the
> > stack.
>
> It may be worth noting that OP_TXHASH can be further decomposed into
> OP_TX (and OP_TAGGEDHASH, or just reuse OP_SHA256).
>
> OP_TX would place the concatenated selected fields onto the stack
> (rather than hashing them) This is more compact for some tests
> (e.g. testing tx version for 2 is "OP_TX(version) 1 OP_EQUALS" vs
> "OP_TXHASH(version) 012345678...aabbccddeeff OP_EQUALS"), and also range
> testing (e.g amount less than X or greater than X, or less than 3 inputs).
>
> > I believe the difficulties with upgrading TXHASH can be mitigated by
> > designing a robust set of TXHASH flags from the start.  For example
> having
> > bits to control whether (1) the version is covered; (2) the locktime is
> > covered; (3) txids are covered; (4) sequence numbers are covered; (5)
> input
> > amounts are covered; (6) input scriptpubkeys are covered; (7) number of
> > inputs is covered; (8) output amounts are covered; (9) output
> scriptpubkeys
> > are covered; (10) number of outputs is covered; (11) the tapbranch is
> > covered; (12) the tapleaf is covered; (13) the opseparator value is
> > covered; (14) whether all, one, or no inputs are covered; (15) whether
> all,
> > one or no outputs are covered; (16) whether the one input position is
> > covered; (17) whether the one output position is covered; (18) whether
> the
> > sighash flags are covered or not (note: whether or not the sighash flags
> > are or are not covered must itself be covered).  Possibly specifying
> which
> > input or output position is covered in the single case and whether the
> > position is relative to the input's position or is an absolute position.
>
> These easily map onto OP_TX, "(1) the version is pushed as u32, (2) the
> locktime is pushed as u32, ...".
>
> We might want to push SHA256() of scripts instead of scripts themselves,
> to reduce possibility of DoS.
>
> I suggest, also, that 14 (and similarly 15) be defined two bits:
> 00 - no inputs
> 01 - all inputs
> 10 - current input
> 11 - pop number from stack, fail if >= number of inputs or no stack elems.
>
> Cheers,
> Rusty.
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>

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  reply	other threads:[~2022-02-08  4:34 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-26 17:20 [bitcoin-dev] TXHASH + CHECKSIGFROMSTACKVERIFY in lieu of CTV and ANYPREVOUT Russell O'Connor
2022-01-26 22:16 ` Jeremy
2022-01-27  4:20   ` James Lu
2022-01-27 19:16   ` Russell O'Connor
2022-01-28  0:18     ` James O'Beirne
2022-01-28 13:14       ` Michael Folkson
2022-01-28 14:17         ` Anthony Towns
2022-01-28 16:38           ` Jeremy
2022-01-28 14:13       ` Russell O'Connor
2022-01-28 15:14         ` James O'Beirne
2022-01-29 15:43           ` Russell O'Connor
2022-01-29 17:02             ` Jeremy Rubin
     [not found]             ` <CAD5xwhjHv2EGYb33p2MRS=VSz=ciGwAsiafX1yRHjxQEXfykSA@mail.gmail.com>
2022-01-29 17:14               ` Russell O'Connor
2022-01-31  2:18       ` Anthony Towns
2022-01-28  1:34 ` Anthony Towns
2022-01-28 13:56   ` Russell O'Connor
2022-02-01  1:16     ` Anthony Towns
2022-02-08  2:16       ` Russell O'Connor
2022-02-17 14:27         ` Anthony Towns
2022-02-17 14:50           ` Russell O'Connor
2022-02-08  3:40 ` Rusty Russell
2022-02-08  4:34   ` Jeremy Rubin [this message]
2022-02-11  0:55     ` [bitcoin-dev] Recursive covenant opposition, or the absence thereof, was " David A. Harding
2022-02-11  3:42       ` Jeremy Rubin
2022-02-11 17:42       ` James O'Beirne
2022-02-11 18:12         ` digital vagabond
2022-02-12 10:54           ` darosior
2022-02-12 15:59             ` Billy Tetrud
2022-02-17 15:15           ` Anthony Towns
2022-02-18  7:34       ` ZmnSCPxj
2022-02-23 11:28       ` ZmnSCPxj
2022-02-23 18:14         ` Paul Sztorc
2022-02-24  2:20           ` ZmnSCPxj
2022-02-24  6:53         ` Anthony Towns
2022-02-24 12:03           ` ZmnSCPxj
2022-02-26  5:38             ` Billy Tetrud
2022-02-26  6:43               ` ZmnSCPxj
2022-02-27  0:58                 ` Paul Sztorc
2022-02-27  2:00                   ` ZmnSCPxj
2022-02-27  7:25                     ` ZmnSCPxj
2022-02-27 16:59                       ` Billy Tetrud
2022-02-27 23:50                         ` Paul Sztorc
2022-02-28  0:20                     ` Paul Sztorc
2022-02-28  6:49                       ` ZmnSCPxj
2022-02-28  7:55                         ` vjudeu
2022-03-04  8:42                           ` ZmnSCPxj
2022-03-04 13:43                             ` vjudeu
2022-02-28 22:54                         ` Paul Sztorc
2022-03-01  5:39                           ` Billy Tetrud
2022-03-02  0:00                             ` Paul Sztorc
2022-03-04 12:35                               ` Billy Tetrud
2022-03-04 20:06                                 ` Paul Sztorc
2022-02-26  6:00             ` Anthony Towns
2022-02-15  8:45     ` [bitcoin-dev] " Rusty Russell
2022-02-15 18:57       ` Jeremy Rubin
2022-02-15 19:12         ` Russell O'Connor
2022-02-16  2:26         ` Rusty Russell
2022-02-16  4:10           ` Russell O'Connor

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