Date: Tue, 10 May 2022 19:03:16 +0000
To: ZmnSCPxj <ZmnSCPxj@protonmail.com>,
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
From: AdamISZ <AdamISZ@protonmail.com>
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Subject: Re: [bitcoin-dev] BIP proposal: Timelocked address fidelity bond
	for BIP39 seeds
Precedence: list

------- Original Message -------
On Tuesday, May 10th, 2022 at 17:54, ZmnSCPxj via bitcoin-dev <bitcoin-dev@=
lists.linuxfoundation.org> wrote:


> Good morning waxwing,
<snip>
>
> Ah, yes, now I remember.
> I discussed this with Tamas as well in the past and that is why we conclu=
ded that in defiads, each UTXO can host at most one advertisement at any on=
e time.
> In the case of defiads there would be a sequence counter where a higher-s=
equenced advertisement would replace lower-sequenced advertisement, so you =
could update, but at any one time, for a defiads node, only one advertiseme=
nt per UTXO could be used.
> This assumed that there would be a defiads network with good gossip propa=
gation so our thinking at the time was that a higher-sequenced advertisemen=
t would quickly replace lower-sequenced ones on the network.
> But it is simpler if such replacement would not be needed, and you could =
then commit to the advertisement directly on the UTXO via a tweak.
>
> Each advertisement would also have a specific application ID that it appl=
ied to, and applications on top of defiads would ask the local defiads node=
 to give it the ads that match a specific application ID, so a UTXO could o=
nly be used for one application at a time.
> This would be equivalent to domain separation tags that waxwing mentions.
>
> Regards,
> ZmnSCPxj
>

I suppose ultimately this brings up the question of the scope of this BIP. =
The abstract points out that the BIP contains both a definition of address =
derivation, but also how to sign fidelity bond certificates.

My feeling is that the latter might be better not included? I note that the=
 'Motivation' section gives motivation for standardisation of derivation (t=
his includes things like time schedule), but not the second area - certific=
ate signing. I think the second area is much more tricky, but much more to =
the point is, isn't it the case that that second area, can be interpreted w=
ithout consensus between wallet developers? So say you were a hardware wall=
et provider, or a "node in a box" provider - your customers want you to pro=
vide the ability move funds around, including e.g. moving funds out of an o=
ld Joinmarket wallet (in which say there is a now expired timelock address =
utxo) by just entering its BIP39 seed. If this BIP addresses that, it shoul=
d be enough.

I don't doubt that there's gains to be had from a broader community discuss=
ing and agreeing the details of how to create a fidelity bond certificate, =
but it's a separate, and more difficult, task.

Cheers,
waxwing/AdamISZ