From: Xiaohui Liu <x.liu@scrypt•io>
To: Bitcoin Development Mailing List <bitcoindev@googlegroups.com>
Subject: Re: [bitcoindev] Signing a Bitcoin Transaction with Lamport Signatures (no changes needed)
Date: Fri, 15 Nov 2024 13:54:08 -0800 (PST) [thread overview]
Message-ID: <129a9605-7a91-42a7-a9ef-07de6662ca7en@googlegroups.com> (raw)
In-Reply-To: <ZjD-dMMGxoGNgzIg@camus>
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Hi,
How does covenant work without OP_CAT here, assuming no size limit? Don't
you still need OP_CAT to parse/introspect fields (e.g., input/output) of
the spending transaction?
Regards,
sCrypt
On Tuesday, April 30, 2024 at 7:22:54 AM UTC-7 Andrew Poelstra wrote:
> On Tue, Apr 30, 2024 at 08:32:42AM -0400, Matthew Zipkin wrote:
> > > if an attacker managed to grind a 23-byte r-value at a cost of 2^72
> > computations, it would provide the attacker some advantage.
> >
> > If we are assuming discrete log is still hard, why do we need Lamport
> > signatures at all? In a post-quantum world, finding k such that r is 21
> > bytes or less is efficient for the attacker.
> >
>
> Aside from Ethan's point that a variant of this technique is still
> secure in the case that discrete log is totally broken (or even
> partially broken...all we need is that _somebody_ is able to find the
> discrete log of the x=1 point and for them to publish this).
>
> Another reason this is useful is that if you have a Lamport signature on
> the stack which is composed of SIZE values, all of which are small
> enough to be manipulated with the numeric script opcodes, then you can
> do covenants in Script.
>
> (Sadly(?), I think none of this works in the context of the 201-opcode
> limit...and absent BitVM challenge-response tricks it's unlikely you can
> do much in the context of the 4MWu block size limit..), but IMO it's a
> pretty big deal that size limits are now the only reason that Bitcoin
> doesn't have covenants.)
>
> --
> Andrew Poelstra
> Director, Blockstream Research
> Email: apoelstra at wpsoftware.net
> Web: https://www.wpsoftware.net/andrew
>
> The sun is always shining in space
> -Justin Lewis-Webster
>
>
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next prev parent reply other threads:[~2024-11-15 22:02 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-29 0:30 Ethan Heilman
2024-04-30 12:32 ` Matthew Zipkin
2024-04-30 13:25 ` Ethan Heilman
2024-04-30 14:21 ` Andrew Poelstra
2024-04-30 20:43 ` Ethan Heilman
2024-05-01 3:46 ` Antoine Riard
2024-05-01 20:02 ` Ethan Heilman
2024-05-06 7:39 ` David A. Harding
2024-05-06 16:48 ` Andrew Poelstra
2024-05-06 18:56 ` David A. Harding
2024-05-06 19:06 ` Andrew Poelstra
2024-05-07 0:55 ` Antoine Riard
2024-05-07 16:05 ` Ethan Heilman
2024-05-07 4:11 ` David A. Harding
2024-05-07 14:34 ` Andrew Poelstra
2024-05-09 0:31 ` Ben Carman
2024-05-09 12:46 ` Andrew Poelstra
2024-05-11 2:53 ` Antoine Riard
[not found] ` <91ba7058-776d-4ff0-a179-bb2917ef03ffn@googlegroups.com>
[not found] ` <CAEM=y+UKgDRtaV5uveiX_Hn1dTDEF-DSHw0SjRu+j0s3fmp78Q@mail.gmail.com>
[not found] ` <CAOY=fzk+nKBw4kpLJLe=EngNfD5iEsWVsa5sMyPaXKp9cDAqdQ@mail.gmail.com>
[not found] ` <CAOY=fz=bcun5U75PUJJGuuB7p5dHtghrYf9gfOvj4zpiWdM_Tg@mail.gmail.com>
2024-10-25 0:20 ` Vicky
2024-10-25 9:58 ` Garlo Nicon
2024-11-15 21:54 ` Xiaohui Liu [this message]
2024-11-16 14:55 ` Ethan Heilman
[not found] ` <CAMrCH3hCN0KAiE0AdLTA8i004-R9FACpMZvQTiM_78RAxf1zbA@mail.gmail.com>
2024-11-17 21:59 ` Ethan Heilman
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