Fixing SSL (was Re: Dutch Transport Card Broken)

[Dave Howe]

Philipp Gühring wrote:
> I once implemented SSL over GSM data channel (without PPP and without
> TCP), and discovered that SSL needs better integrity protection than
> raw GSM delivers. (I am quite sure that´s why people normally run PPP
> over GSM channels ...) SSH has the same problems. It also assumes an
> active attack in case of integrity problems of the lower layer, and
> terminates the connection.

TBH I can't see the problem - the unix philosophy of doing one thing
well, and chaining simple tools to make complex ones, works well here.

we have:

TCP - well understood, has crude integrity and reliability checks built
in, works reasonably well at converting a bunch of packets leaving and
arriving via your network connection into something vaguely like a
stream point-to-point connection. Provided by every ISP across the
planet, problems at this level can be handed off to experienced network
engineers who will at least understand the problem.

SSL - Cludge thrown together by a browser manufacturer, probably to
create a market for a bunch of companies who generated two prime numbers
and now sell the answers to simple math queries involving the numbers.
However, works reasonably well, has some crude authentication of the
server built in (via the aformentioned bunch of companies) which at
least limits potential hackers to those whose money the bunch of
companies will accept ;)
   Again, works well in its domain, but requires a reasonably reliable
channel to talk over, and a message to carry. Effectively turns an
unencrypted channel into an encrypted one, Would work as well over a
serial link as a tcp link (modulo the domain name check in the cert)

HTTP - pretty basic file transfer protocol, with limited scope for
negotiation, but designed largely to move text files from a server to a
client. requires transport, can use tcp, ssl-over-tcp, serial, whatever
your server will listen on and your client request on.

add them together and you get HTTPS. leave out the SSL, and you get HTTP
as-normally-spoke, so the SSL and HTTP are pretty much drop in modules.
you could define HTTPG (HTTP over a security protocol other than SSL)
and if a browser could support it, both TCP and HTTP would still be
happy. you could also define HTTPS-over-adis-lamp and provided the
operators were sufficiently accurate, securely download your web page
from a server on a nearby hilltop after dark by replacing the TCP layer :)

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