Subject: [TLS] Re: FATT Chance: On the Robustness of Standalone and Hybrid ML-KEM Key Exchange in TLS 1.3
From: Viktor Dukhovni <[email-masked]>
To: [email-masked]
Date: Mon, 8 Jun 2026 18:27:53 +1000
List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." <tls.ietf.org>

On Mon, Jun 08, 2026 at 09:33:49AM +0200, Simon Josefsson wrote:

> The above argument is often repeated, but I think there are naunces that
> get lost when phrased like that.  Security is rarely binary either or,
> but more of a spectrum.  All ECDSA keys in the world won't automatically
> be revealed on the first day a CRQC is demonstrated.  People still run
> RSA 1024 deployments (e.g., DNSSEC)

In DNSSEC, ECDSA P-256 exceeds the deployment of RSA, and with RSA
domains, the KSKs are most commonly 2048 bits, with RSA-1024 KSKs on
only ~0.2% of signed domains.  Yes, migration to PQC will take time.

Today's numbers:

 - Algorithm frequencies:
    https://stats.dnssec-tools.org/#/?dnssec_param_tab=0

        KSK Alg                Domain count
        13 (ECDSA P-256)    |  14891802
        8  (RSA SHA2-256)   |  10202696
        15 (Ed25519)        |  576447
        10 (RSA SHA2-512)   |  179838
        14 (ECDSA P-384)    |  166224
        7  (RSA SHA1 NSEC3) |  73316
        5  (RSA SHA1)       |  11194

 - RSA KSK bit count frequencies:
    https://stats.dnssec-tools.org/#/?dnssec_param_tab=2

        Bits     Domain Count
        2048  |  10008497
        4096  |  405294
        1024  |  24925
        1280  |  17001
        1536  |  5251
        3072  |  2138
        512   |  388
        2024  |  148
        2560  |  139

For ZSKs (that are much easier to rotate, if the operator bothers)
RSA-1024 is dominant at ~90%.

 - RSA ZSK bit count frequencies:
    https://stats.dnssec-tools.org/#/?dnssec_param_tab=3

        Bits     Domain Count
        1024  |  9039068
        2048  |  1066378
        4096  |  72116
        1280  |  8079
        3072  |  2753
        512   |  433
        1032  |  277
        1536  |  271
        2304  |  137

-- 
    Viktor.  🇺🇦 Слава Україні!