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Re: Please save the pre-shared key mode
Alex Alten wrote:
>
> Jan,
>
> Cut it out. Going PK implies PKI, which in turn implies X.509.
Nonsense.
Public key techniques can be used without any infrastructure at
all, and without certificates. FreeS/WAN (www.freeswan.org) has
been doing this, with RSA keys, for some time. There are no
signatures on the keys. They are not embedded in certificates.
This code is in widespread use, and works just fine.
There are only two real problems with this.
One is that you need to authenticate transferred public keys with
some out-of-band method. This is much easier to do securely than
transferring shared secrets, but can still require careful work,
especially in a large network.
The other is that the IPsec RFCs do not specify a format for RSA
key exchange, so various implementers can make different choices
and then have their products fail to interoperate. This can and
should be fixed in a revised standard, or perhaps in a BCP RFC.
It is also clearly possible to do more than this without going
to a full PK infrastructure. Have one signing key, known to all
players and controlled by an organisation's central admin folk.
Require all keys used in IPsec to be signed by that key. This
gives some advantages over the plain RSA keys, providing an
authentication mechanism, without anything like the full
complexity of PKI.
References: