Subject: [IPsec] 3GPP question about ECDSA support

From: John Mattsson <[email-masked]>
Date: Fri, 22 Jul 2016 17:46:36 +0000

3GPP is currently apopting ECDSA for all uses of IKEv2 (older releases
used RSA). My 3GPP SA3 colleagues (cc) have asked me to forward the
question below to the IPSec wg. As discussed in Buenos Aires, 3GPP and
IETF should coordinate more, I hope the IPSec wg can provide valuable
feedback.

Cheers,
John

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Hi all,

I have a question regarding support of ECDSA and I hope to get some views
on this list.

3GPP has introduced ECDSA for IKEv2 in 3GPP specification TS 33.310 and is
now considering, which RFC should be adopted regarding ECDSA, RFC 4754 or
RFC 7427?

We basically would like to understand better what is the future for ECDSA
and RSA authentication and especially if there is information on what is
the deployment status of RFC4754 and RFC7427.

Any views on this would be appreciated.

Br, Vesa Lehtovirta
----------------------------------------------------

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From: Paul Wouters <[email-masked]>
Date: Fri, 22 Jul 2016 13:56:35 -0400 (EDT)

On Fri, 22 Jul 2016, John Mattsson wrote:

> Subject: [IPsec] 3GPP question about ECDSA support
>

See https://tools.ietf.org/html/draft-ietf-ipsecme-rfc4307bis-07#section-4

While the old style "auth by IKE algorithm number" are still at SHOULD,
they will be demoted in the near future because we are promoting using
Digital Signatures as per RFC 7427 instead.

https://tools.ietf.org/html/rfc7427

As the draft states:

    RSA authentication, as well as other specific
    Authentication Methods, are expected to be replaced with the generic
    Digital Signature method of [RFC7427].

    [...]

    ECDSA based Authentication Methods are also expected to be downgraded
    as it does not provide hash function agility.  Instead, ECDSA (like
    RSA) is expected to be performed using the generic Digital Signature
    method.

The advantage is that the AUTH algorithm will be negotiated by OID and
be independent of any IKE/IPsec RFC's.

New standards should really only use 7427 for authentication.

ECDSA should be supported via RFC-7427 and not via the legacy IKE
algorithm numbers.

Paul