MIME-Version: 1.0
From: Nadav Ivgi <nadav@shesek.info>
Date: Wed, 29 Jul 2020 18:10:42 +0300
Message-ID: <CAGXD5f3SiXHOmjSVxUQWOLT5SocQ62qTNGJOmTUtW7kDeduFjA@mail.gmail.com>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Content-Type: multipart/alternative; boundary="00000000000053ca9f05ab95f628"
Subject: [bitcoin-dev] Minsc, a Miniscript-based scripting language
Precedence: list

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Hi all,

I recently released Minsc, a high-level scripting language for expressing
Bitcoin Script spending conditions using a simple and familiar syntax.

Minsc is based on the Miniscript Policy language, with additional features
and syntactic sugar sprinkled on top, including variables, functions, infix
notation, human-readable times and more.

A live compiler (Minsc->Policy->Miniscript->Script) and documentation are
available on the website: https://min.sc

Source code (in Rust) is available on github:
https://github.com/shesek/minsc

Some example Minsc scripts:

- A user and a 2FA service need to sign off, but after 90 days the user
alone is enough

      pk(user_pk) && (9@pk(service_pk) || older(90 days))

- Traditional preimage-based HTLC

      $redeem =3D pk(A) && sha256(H);
      $refund =3D pk(B) && older(10);

      likely@$redeem || $refund

- Liquid-like federated pegin with emergency recovery keys

      $federation =3D 4 of [ pk(A), pk(B), pk(C), pk(D), pk(E) ];
      $recovery =3D 2 of [ pk(F), pk(G), pk(H) ];
      $timeout =3D older(heightwise 2 weeks);

      likely@$federation || ($timeout && $recovery)

- The BOLT #3 received HTLC policy

      fn htlc_received($revoke_pk, $local_pk, $remote_pk, $secret, $delay) =
{
        $success =3D pk($local_pk) && hash160($secret);
        $timeout =3D older($delay);

        pk($revoke_pk) || (pk($remote_pk) && ($success || $timeout))
      }

      htlc_received(A, B, C, H, 3 hours)

- 2FA where the user has a 2-of-2 setup and the service provider is a
3-of-4 federation

      fn two_factor($user, $provider, $delay) =3D
        $user && (likely@$provider || older($delay));

      $user =3D pk(user_desktop) && pk(user_mobile);
      $providers =3D [ pk(P1), pk(P2), pk(P3), pk(P4) ];

      two_factor($user, 3 of $providers, 4 months)

- Easily add NSA backdoors to everything =F0=9F=95=B5=EF=B8=8F=F0=9F=9A=AA

      _backdoor=3Dpk(usgovt), _pk=3Dpk, _older=3Dolder, _after=3Dafter,
      _sha256=3Dsha256, _ripemd160=3Dripemd160;

      fn pk(x) =3D _pk(x) || _backdoor;
      fn older(x) =3D _older(x) || _backdoor;
      fn after(x) =3D _after(x) || _backdoor;
      fn sha256(x) =3D _sha256(x) || _backdoor;
      fn ripemd160(x) =3D _ripemd160(x) || _backdoor;

      (pk(A) && sha256(H)) || (pk(B) && older(10))

Feedback is appreciated!

Nadav

P.S Since every Miniscript Policy is also a valid Minsc expression, the
min.sc web code editor UI could also be useful for experimenting with bare
policies. You'll get syntax highlighting, parentheses matching, real-time
compilation (in a web worker so the browser doesn't freeze) and syntax
error reporting.

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<div dir=3D"ltr"><div>Hi all,<br></div><div><br></div><div>I recently relea=
sed Minsc, a high-level scripting language for expressing Bitcoin Script sp=
ending conditions using a simple and familiar syntax.</div><br>Minsc is bas=
ed on the Miniscript Policy language, with additional features and syntacti=
c sugar sprinkled on top, including variables, functions, infix notation, h=
uman-readable times and more.<br><br>A live compiler (Minsc-&gt;Policy-&gt;=
Miniscript-&gt;Script) and documentation are available on the website: <a h=
ref=3D"https://min.sc">https://min.sc</a><br><br>Source code (in Rust) is a=
vailable on github: <a href=3D"https://github.com/shesek/minsc">https://git=
hub.com/shesek/minsc</a><br><br>Some example Minsc scripts:<br><br>- A user=
 and a 2FA service need to sign off, but after 90 days the user alone is en=
ough<br><br>=C2=A0 =C2=A0 =C2=A0 pk(user_pk) &amp;&amp; (9@pk(service_pk) |=
| older(90 days))<br><br>- Traditional preimage-based HTLC<br><br>=C2=A0 =
=C2=A0 =C2=A0 $redeem =3D pk(A) &amp;&amp; sha256(H);<br>=C2=A0 =C2=A0 =C2=
=A0 $refund =3D pk(B) &amp;&amp; older(10);<br><br>=C2=A0 =C2=A0 =C2=A0 lik=
ely@$redeem || $refund<br><br>- Liquid-like federated pegin with emergency =
recovery keys<br><br>=C2=A0 =C2=A0 =C2=A0 $federation =3D 4 of [ pk(A), pk(=
B), pk(C), pk(D), pk(E) ];<br>=C2=A0 =C2=A0 =C2=A0 $recovery =3D 2 of [ pk(=
F), pk(G), pk(H) ];<br>=C2=A0 =C2=A0 =C2=A0 $timeout =3D older(heightwise 2=
 weeks);<br><br>=C2=A0 =C2=A0 =C2=A0 likely@$federation || ($timeout &amp;&=
amp; $recovery)<br><br>- The BOLT #3 received HTLC policy<br><br>=C2=A0 =C2=
=A0 =C2=A0 fn htlc_received($revoke_pk, $local_pk, $remote_pk, $secret, $de=
lay) {<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 $success =3D pk($local_pk) &amp;&amp;=
 hash160($secret);<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 $timeout =3D older($delay=
);<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 <br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 pk($revok=
e_pk) || (pk($remote_pk) &amp;&amp; ($success || $timeout))<br>=C2=A0 =C2=
=A0 =C2=A0 }<br><br>=C2=A0 =C2=A0 =C2=A0 htlc_received(A, B, C, H, 3 hours)=
<br><br>- 2FA where the user has a 2-of-2 setup and the service provider is=
 a 3-of-4 federation<br><br>=C2=A0 =C2=A0 =C2=A0 fn two_factor($user, $prov=
ider, $delay) =3D <br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 $user &amp;&amp; (likely@=
$provider || older($delay));<br><br>=C2=A0 =C2=A0 =C2=A0 $user =3D pk(user_=
desktop) &amp;&amp; pk(user_mobile);<br>=C2=A0 =C2=A0 =C2=A0 $providers =3D=
 [ pk(P1), pk(P2), pk(P3), pk(P4) ];<br>=C2=A0 =C2=A0 =C2=A0 <br>=C2=A0 =C2=
=A0 =C2=A0 two_factor($user, 3 of $providers, 4 months)<br><br>- Easily add=
 NSA backdoors to everything =F0=9F=95=B5=EF=B8=8F=F0=9F=9A=AA<br><br>=C2=
=A0 =C2=A0 =C2=A0 _backdoor=3Dpk(usgovt), _pk=3Dpk, _older=3Dolder, _after=
=3Dafter,<br>=C2=A0 =C2=A0 =C2=A0 _sha256=3Dsha256, _ripemd160=3Dripemd160;=
<br><br>=C2=A0 =C2=A0 =C2=A0 fn pk(x) =3D _pk(x) || _backdoor;<br>=C2=A0 =
=C2=A0 =C2=A0 fn older(x) =3D _older(x) || _backdoor;<br>=C2=A0 =C2=A0 =C2=
=A0 fn after(x) =3D _after(x) || _backdoor;<br>=C2=A0 =C2=A0 =C2=A0 fn sha2=
56(x) =3D _sha256(x) || _backdoor;<br>=C2=A0 =C2=A0 =C2=A0 fn ripemd160(x) =
=3D _ripemd160(x) || _backdoor;<br><br>=C2=A0 =C2=A0 =C2=A0 (pk(A) &amp;&am=
p; sha256(H)) || (pk(B) &amp;&amp; older(10))<br><br>Feedback is appreciate=
d!<br><br>Nadav<br><br>P.S Since every Miniscript Policy is also a valid Mi=
nsc expression, the <a href=3D"http://min.sc">min.sc</a> web code editor UI=
 could also be useful for experimenting with bare policies. You&#39;ll get =
syntax highlighting, parentheses matching, real-time compilation (in a web =
worker so the browser doesn&#39;t freeze) and syntax error reporting.</div>

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