Re: [babel] BASE64 and hex encoding HMAC keys for user presentation

Juliusz Chroboczek <jch@irif.fr> Sat, 22 December 2018 16:25 UTC

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Date: Sat, 22 Dec 2018 17:25:43 +0100
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From: Juliusz Chroboczek <jch@irif.fr>
To: Dave Taht <dave.taht@gmail.com>
Cc: babel-users <babel-users@lists.alioth.debian.org>, Babel at IETF <babel@ietf.org>
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Subject: Re: [babel] BASE64 and hex encoding HMAC keys for user presentation
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> I would like the bird and babel implementations to allow for and use
> BASE64 and hex encodings.

> This allows for a shorter, more human friendly representation of both
> cryptographically generated keys and the keys humans are more likely
> to remember and type without error. In the latter case, guidelines as
> to length, mixed case and punctuation would be useful.

I think that the HMAC key should be generated automatically.  I'd hope
that any actual production deployment of HMAC would generate HMAC keys
either randomly or by using a suitable KDF (or whatever the right acronym
is) and distribute it automatically.

(At the current time, I'm not advocating designing a key distribution
protocol to go with HMAC -- I'm in favour of using a centralised script
that uses ssh to distribute keys.  Please see https://cr.yp.to/djbdns/tcp.html)

So no, I'd rather not encourage people to generate HMAC keys manually.

-- Juliusz