From: Tom Trevethan <tom@commerceblock•com>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: [bitcoin-dev] Fwd: Blinded 2-party Musig2
Date: Thu, 27 Jul 2023 14:25:33 +0100 [thread overview]
Message-ID: <CAJvkSsea+aKJFkNpNxHPAGCxrYwU+8wXOzV-8yH=qacGta++ig@mail.gmail.com> (raw)
In-Reply-To: <CAJvkSsfa8rzbwXiatZBpwQ6d4d94yLQifK8gyq3k-rq_1SH4OQ@mail.gmail.com>
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@Jonas
OK, thanks, I get the logic now. I believe this attack can be mitigated (at
least in the case of using this scheme for statechains) by the receiver of
a coin verifying the construction of all previous challenges.
So in this case, the sender of a coin would record R2[K-1] in addition to m
(and any c blinding nonce used) for the signature it generates with the
server. It would then send this (and all previous R2 values i = 0, ...,
K-2) to the receiver.
The receiver would then query the server for the full set (i = 0, ..., K-1)
of R1[i] values it has generated, and the corresponding (blinded) c[i]
values used for each co-signing it has performed on this key. The
receiver would then verify that each previous c[i] (i = 0, ... K-1) has
been correctly formed and includes the server generated R1[i].
If any of the c values fail to verify against the values of R1 provided by
the server, then the coin is invalid.
On Thu, Jul 27, 2023 at 9:08 AM Jonas Nick <jonasdnick@gmail•com> wrote:
> No, proof of knowledge of the r values used to generate each R does not
> prevent
> Wagner's attack. I wrote
>
> > Using Wagner's algorithm, choose R2[0], ..., R2[K-1] such that
> > c[0] + ... + c[K-1] = c[K].
>
> You can think of this as actually choosing scalars r2[0], ..., r2[K-1] and
> define R2[i] = r2[i]*G. The attacker chooses r2[i]. The attack wouldn't
> make
> sense if he didn't.
>
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next prev parent reply other threads:[~2023-07-27 13:25 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-24 7:46 [bitcoin-dev] " Tom Trevethan
2023-07-24 10:50 ` ZmnSCPxj
2023-07-24 14:25 ` Erik Aronesty
2023-07-24 16:08 ` Tom Trevethan
2023-07-24 15:57 ` Tom Trevethan
2023-07-24 14:12 ` Jonas Nick
2023-07-24 14:40 ` Erik Aronesty
2023-07-24 15:40 ` Jonas Nick
2023-07-24 16:51 ` AdamISZ
2023-07-25 14:12 ` Erik Aronesty
2023-07-25 16:05 ` Tom Trevethan
2023-07-26 4:09 ` Erik Aronesty
2023-07-26 17:40 ` Andrew Poelstra
2023-07-26 19:59 ` Jonas Nick
2023-07-26 20:35 ` Tom Trevethan
2023-07-26 22:06 ` Erik Aronesty
2023-07-27 2:54 ` Lloyd Fournier
2023-07-27 8:07 ` Jonas Nick
[not found] ` <CAJvkSsfa8rzbwXiatZBpwQ6d4d94yLQifK8gyq3k-rq_1SH4OQ@mail.gmail.com>
2023-07-27 13:25 ` Tom Trevethan [this message]
2023-08-07 0:55 ` Tom Trevethan
2023-08-08 17:44 ` moonsettler
2023-08-09 15:14 ` Tom Trevethan
2023-08-10 3:30 ` Lloyd Fournier
2023-08-10 11:59 ` Tom Trevethan
2023-08-14 6:31 ` Lloyd Fournier
2023-08-30 10:52 ` Tom Trevethan
2023-07-24 15:39 ` Jonas Nick
2023-07-24 16:22 ` Tom Trevethan
2023-07-26 9:44 ` moonsettler
2023-07-26 14:59 ` Jonas Nick
2023-07-26 19:19 ` AdamISZ
2023-07-26 19:28 ` moonsettler
2023-07-27 5:51 ` AdamISZ
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