From: Adam Stiles <ajstiles@gmail.com>
To: Nico Schottelius <nico.schottelius@ungleich.ch>
Cc: wireguard@lists.zx2c4.com
Subject: Re: How to verify a wireguard public key?
Date: Thu, 24 Dec 2020 15:42:00 -0800 [thread overview]
Message-ID: <CAB5G8p9nCdxkikyubjfjJ4bB4+9LXNrEbCN+ONfZn28g26WE0Q@mail.gmail.com> (raw)
In-Reply-To: <87k0t75h3e.fsf@ungleich.ch>
Hi Nico,
WireGuard uses Curve25519 keys. A Curve25519 secret key is a random 32
byte value with a few special bits flipped, and a public key is
calculated from a secret key.
There's some good info here (https://cr.yp.to/ecdh.html), including
this questions and answer:
"How do I validate Curve25519 public keys?"
"Don't. The Curve25519 function was carefully designed to allow all
32-byte strings as Diffie-Hellman public keys."
I just saw Jason's response, and so this is a bit redundant, but the
reference above is a good one.
Best,
Adam
On Thu, Dec 24, 2020 at 3:21 PM Nico Schottelius
<nico.schottelius@ungleich.ch> wrote:
>
>
> Good morning,
>
> I am currently extending uncloud [0] to support wireguard tunnels and
> keys. At the moment it is not entirely clear how to verify that a
> certain string is a valid wireguard key.
>
> I first tried checking that it is valid base64, but not all base64
> strings are valid wireguard keys.
>
> Then I tried using `echo $key | wg pubkey && echo ok` - which seems to
> check the key format, however the intended behaviour here is misused.
>
> Does anyone have a pointer on how to reliably identify wireguard public
> keys?
>
> Is the wireguard key always 32 bytes when decoded from base64? Tests
> with a number of public keys seems to indicate that.
>
> Best regards,
>
> Nico
>
>
> [0] https://code.ungleich.ch/uncloud/uncloud
>
> --
> Modern, affordable, Swiss Virtual Machines. Visit www.datacenterlight.ch
next prev parent reply other threads:[~2020-12-25 14:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-24 16:00 Nico Schottelius
2020-12-24 23:30 ` Jason A. Donenfeld
2020-12-24 23:42 ` Adam Stiles [this message]
2020-12-25 9:10 ` Nico Schottelius
2020-12-25 23:37 ` Matthias May
2020-12-25 23:47 ` Jason A. Donenfeld
2020-12-25 22:16 ` Matthias Urlichs
2020-12-26 8:09 ` Nico Schottelius
2020-12-26 9:03 ` Matthias Urlichs
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