Date: Mon, 3 Jul 2017 08:05:40 +0300
From: Lars Wirzenius <liw@liw.fi>
To: Wladimir Palant <gtiobnam@palant.de>
Message-ID: <20170703050540.p5co243yxedvsaca@liw.fi>
References: <2d0a8c01-9f58-1ee7-7e20-53fe65d96718@palant.de>
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In-Reply-To: <2d0a8c01-9f58-1ee7-7e20-53fe65d96718@palant.de>
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Cc: obnam-dev@obnam.org
Subject: Re: [rfc] Passphrase-based encryption
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On Mon, Jul 03, 2017 at 12:14:44AM +0200, Wladimir Palant wrote:
> Hi,
>=20
> with GPG being great and all that, I'd still prefer having the option to =
use
> a plain passphrase and AES encryption with obnam. IMHO, this approach has
> two advantages:
>=20
> * Considerably simpler setup, you merely need to come up with a high-entr=
opy
> passphrase.
> * Much easier to back up - you don't need to worry about losing the
> passphrase due to a hard drive crash. If you are afraid of forgetting it,
> then writing it down and keeping somewhere safe will do.

If you want this, you should write a plugin that adds symmetric
encryption in addition to the PGP based on that Obnam currently
provides. You should probably do it by only encrypting the symmetric
encryption key that PGP encrypts. This would allow PGP and symmetric
to be used on the same repo by different clients.

I am afraid, however, that I am unlikely to accept the plugin into
Obnam proper, since I don't think it makes things better. It's true
that it will probably be easier to set up, but at the cost of more
difficult key management.

Backing up small files such as PGP keys is so easy I don't agree with
that part of your argument. It's a matter of a few kilobytes. You
could put the key into a QR code and print it on paper.

Also, environment variables can be read by other processes, just like
command line arguments can be. See /proc/*/environ. The environ files
are only readable by the owner, but it's still not a way to pass
secrets, in my opinion. Defense in depth, and all that.

> * The current encryption plugin will use /dev/random rather than
> /dev/urandom by default.

Since 1.20 (October 2010) the default is /dev/urandom.

--=20
I want to build worthwhile things that might last. --joeyh

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