Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1.1"

"Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu> Mon, 06 May 2019 17:44 UTC

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From: "Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu>
To: "tls@ietf.org" <tls@ietf.org>
Thread-Topic: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1.1"
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Date: Mon, 6 May 2019 17:44:48 +0000
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Subject: Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1.1"
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On 5/6/19, 7:22 AM, "TLS on behalf of Hubert Kario" <tls-bounces@ietf.org on behalf of hkario@redhat.com> wrote:
    > Sure, and that was the really strange thing with TLS 1.2, why not just say
    > SHA-2 or better only, rather than adding mechanisms that were much, much
    > weaker than its predecessors?  So the simple fix is just to use SHA-2 only
    > for TLS 1.2.
    
    I don't know as I wasn't there when that was discussed, but one reason could 
    be the same as the problems we are facing now with RSA-PSS in TLS 1.3: 
    smartcards and HSMs that are limited to old algorithms.

HSMs are more likely than not to support SHA-2. Smartcards rarely perform hash themselves, relying on the software that uses them.


    Also, don't forget that signature_algorithms, at least in theory[1], was 
    supposed to also influence server certificate selection, and SHA-1 was used in 
    vast majority of certificates in PKI.

Alas. Only in some (albeit large) enclaves.