Date: Wed, 26 Apr 2023 18:37:59 +0000
To: "bitcoin-dev@lists.linuxfoundation.org"
 <bitcoin-dev@lists.linuxfoundation.org>
From: Dr Olga Ukolova <ukolova@mycitadel.io>
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Subject: [bitcoin-dev] MyCitadel wallet v1.3 advances time-locked multi-sigs
	further
Precedence: list

Dear community,


MyCitadel [1] by Pandora Prime SA is a Bitcoin wallet that was first to sup=
port
account-based multi-sigs with time-locks and complex miniscript descriptors=
.
Today an updated version 1.3 is released, extending this support, allowing =
the=20
same signer to participate in multiple spending conditions in SegWit v0
contexts. This enables creation of complex time-locked conditions involving=
=20
the same signers in different spending policies (for instance having 2-of-4=
=20
multi-sig which in 1 year becomes 1-of-2).


Details
=3D=3D=3D=3D=3D=3D=3D

A year ago we created desktop version of MyCitadel: it was the first bitcoi=
n=20
wallet fully written in Rust (using GDK3 framework) and also the first=20
with a support for both branched tapscripts and gracefully degrading=20
time-locked multi-sigs (with the later working for both Taproot and SegWit =
v0).

Today we are happy to inform you about new release v1.3, with two main=20
improvements:

* Creation of degrading time locked multi-sigs in SegWit v0 context, where=
=20
  same device/signer can participate multiple conditions with different=20
  timelocks and multisig thresholds.=20

  NB: Previously, miniscript was preventing from creating SegWit policies=
=20
  re-using the same extended key, while in Taproot it was possible [2].=20
  We have mitigated the problem by introducing account-based spending polic=
ies,=20
  using different account from the same signer in different script branches=
.

* Support for exporting Bitcoin Core/BIP380-compatible wallet descriptors,=
=20
  which include Taproot script tree and miniscript fragments.


More about MyCitadel
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

MyCitadel was designed with approach that avoids touching private keys and=
=20
seeds. Unlike many other wallets, it is based not on BDK but on an
alternative stack of rust libraries called "descriptor wallet library" [3],=
=20
created by the LNP/BP Standards Association [4]. This library provides=20
compile-time type-level guarantees avoiding usage of private keys in wallet=
=20
descriptors, and miniscript fragments. The wallet works with hardware=20
signers, and also can produce and export PSBT files, which may be signed=20
elsewhere (including air gaped devices, or even command-line hot-wallet=20
signers, if needed).


Accessing release
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

If you want to check it out, play with it or leave feedback, please feel
free to go to the release GutHub discussion [5], which also links to the=20
released binaries [6].


Acknowledgements
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

This release was made possible because with the help we received from=20
the NYM project team, which had provided both valuable ideas and financial=
=20
support for continued MyCitadel development.


Thank you.

Regards,
Olga Ukolova
CEO Pandora Prime SA, Switzerland
https://mycitadel.io
Twitter: @mycitadel_io

[1]: https://mycitadel.io
[2]: https://github.com/rust-bitcoin/rust-miniscript/issues/338#issuecommen=
t-1137750428
[3]: https://github.com/BP-WG/descriptor-wallet
[4]: https://www.lnp-bp.org
[5]: https://github.com/mycitadel/mycitadel-desktop/discussions/90
[6]: https://github.com/mycitadel/mycitadel-desktop/releases/tag/v1.3.0