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Date: Fri, 23 May 2014 10:32:34 -0700
Message-ID: <CAAS2fgR39ChTjhmY-wpcgUoHWGJenazQyOaj5=ym5zYOHiFQig@mail.gmail.com>
From: Gregory Maxwell <gmaxwell@gmail.com>
To: Kyle Jerviss <bitcoin-devel@jerviss.org>
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Cc: Bitcoin Development <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] PSA: Please sign your git commits
Precedence: list

On Fri, May 23, 2014 at 9:48 AM, Kyle Jerviss <bitcoin-devel@jerviss.org> w=
rote:
> Multisig is great for irreversible actions, but pointless most of the
> time, which is why no PGP developer or user ever thought to implement it.
>
> If you lose a key and an attacker signs a bogus email or commit with it,
> we all roll back with no lasting harm done.

PGP in general is not very thoughtful about security. There are a lot
of things it does poorly. This is easily excusable considering the
historical context it came from=E2=80=94 it was the first real cryptographi=
c
tool I used, at the time its distribution had concerns about legality,
just getting things into people's hands was an achievement enough.

From a cryptosystem perspective much more powerful things can be done
now, but there is a long way to go in figuring out how to many any
cryptographic tool usable to people.

PGP is a general purpose tool=E2=80=94 which is the hardest kind to write=
=E2=80=94 its
also used in a lot of irreversible contexts: If your key deploys a bad
software release and it steals everyone's data or wipes their disks=E2=80=
=94
thats not an irreversible action by any means.

If you want threshold pgp though=E2=80=94 it's possible. The RSA cryptosyst=
em
is directly compatible with threshold cryptography. It's just that no
one has written the tools. There are implementations of the bare
cryptosystem however.

One of my longer term would-be-nice goals for a upgrade bitcoin script
2.0 would be being thoughtful enough in the design that it could be
adopted as a signing cryptosystem in other applications (e.g. tools
similar to GPG)=E2=80=94 allowing for things like creating a public key whi=
ch
can only issue trust level 0 certifications, only certifications for
certain organizations (e.g. *.debian.org) unless thresholded with an
offline key, or only signing for messages meeting a certain
programmatic predicate generally.