Subject: [perpass] encrypted PPP

From: Nick Thomas <[email-masked]>
Date: Fri, 06 Sep 2013 10:29:19 +0100

Hi all,

PPP gets a lot of use still, especially between EUs and access ISPs,
where it's generally not encrypted. RFC1968 exists, but doesn't actually
seem useful any more.

I'm envisioning a PPP enhancement where EU and ISP can exchange public
keys beforehand, out-of-band if necessary, but it's all extremely fuzzy
at the moment. My access ISP, who I have considerable trust in, has no
real control over the infrastructure between my house and their access
node near London - all that's BT-operated, and they just get to
terminate PPP over it.

Thoughts-in-general?

/Nick

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From: Paul Wouters <[email-masked]>
Date: Fri, 6 Sep 2013 12:25:02 -0400 (EDT)

On Fri, 6 Sep 2013, Nick Thomas wrote:

[ note, using "EU" for "end user" is _very_ confusing ]

> node near London - all that's BT-operated, and they just get to

Any ISP that does not trust the last-mile providers should offer their
customers VPN access via IPsec. Actually, they should offer it
regardless so their users can use a VPN to connect to the ISPs
infrastructure when the user is roaming on his laptop/phone as well.

There is no "ppp encryption" the ISP can add, because the last-mile
provider usually terminates the PPP(OE) session. They need to add
encryption on the resulting IP layer, not below it.

Paul

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From: Dean Willis <[email-masked]>
Date: Fri, 6 Sep 2013 14:14:07 -0500

> encryption on the resulting IP layer, not below it.

I concur completely, but might add that TLS-style VPNs (OpenVPN, for example) can be useful here too. But in either case, there's a significant opex cost for the ISP.

This also means, probably, having VPN software in your router. And the code in your router is probably compromised by NSA, MSS, or both.

--
Dean

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From: Nick Thomas <[email-masked]>
Date: Fri, 06 Sep 2013 20:49:27 +0100

> encryption on the resulting IP layer, not below it.

Having discussed this with my access ISP, they've confirmed that they
are responsible for terminating the PPP session, and could implement
encrypted PPP in principle. Maybe this is ridiculously uncommon, I don't
know.

IPsec is great, and what I'm using over the last mile at the moment, but
encrypting PPP appeals to me a lot. And maybe all that's needed is
updating the list of crypto schemes in RFC1968?

/Nick