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[TLS] Re: [lamps] Re: [EXTERNAL] Re: Re: Re: Re: TLS Client Certificates; a survey

Michael Richardson <mcr+ietf@sandelman.ca> Tue, 07 April 2026 19:31 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
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Date: Tue, 07 Apr 2026 15:31:21 -0400
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Subject: [TLS] Re: [lamps] Re: [EXTERNAL] Re: Re: Re: Re: TLS Client Certificates; a survey
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Peter Gutmann <pgut001=40cs.auckland.ac.nz@dmarc.ietf.org> wrote:
    > This is how rationally-written applications do things [*].  The problem is
    > that, particularly under Windows, it's very easy to get drawn into trusting
    > everything Windows trusts, which means in effect any cert issued by any

Feels like 30 years of this kind of nonsense :-(

    > Does Linux have an equivalent systemwide cert store that everything ends up
    > using?  That is, do people use the NSS cert store or the Chrome cert store as
    > a de facto equivalent of CERT_SYSTEM_STORE_LOCAL_MACHINE or whatever?

No.
1. the Chrome cert store comes with Chrome. Extensions/additions are
   per-account/per-profile.

2. /etc/ssl/certs/ is the "system" trust store, but it comes with no
   authorizations as to CA purpose. I can believe that people make the same
   "trust everything" mistake, but I think it's harder.

    > [*] In my case I tell people to key off the public key fingerprint since proof
    > of control of the user's private key is what matters, not what some random
    > CA decides to sign.  So it's more like AADS than anything-some-CA-signs-we-
    > trust.

Yes... very good advice.
But a pathology I find is that this is far more difficult to pin that than it
should be.      Postfix and fetchmail do very good jobs of logging the
fingerprint that *would* have worked...  The missing part is getting that
potential fingerprint into a database/admin-interface that makes it easy for
the administrator to authorize.

--
Michael Richardson <mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide

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