Re: [DNSOP] [Ext] DNSSEC Strict Mode

Paul Hoffman <paul.hoffman@icann.org> Thu, 25 February 2021 21:21 UTC

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From: Paul Hoffman <paul.hoffman@icann.org>
To: Ben Schwartz <bemasc=40google.com@dmarc.ietf.org>
CC: dnsop <dnsop@ietf.org>
Thread-Topic: [DNSOP] [Ext] DNSSEC Strict Mode
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Date: Thu, 25 Feb 2021 21:21:08 +0000
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Subject: Re: [DNSOP] [Ext] DNSSEC Strict Mode
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On Feb 25, 2021, at 8:06 AM, Ben Schwartz <bemasc=40google.com@dmarc.ietf.org> wrote:
> 
>> On Thu, Feb 25, 2021 at 10:26 AM Paul Hoffman <paul.hoffman@icann.org> wrote:
>> In reading draft-schwartz-dnsop-dnssec-strict-mode, I still don't understand why it is even useful. If I am signing one of my zones with two algorithms, I must intend to do so. What is the value of me saying that only one of the signing algorithms is the strong one?
>> 
> That's not especially the intent.  Currently, if you sign with two algorithms, and either of those algorithms becomes insecure*, your zone becomes susceptible to forgery.  If you mark both algorithms as Strict, then your zone remains secure (for validators who implement both algorithms and this draft).
> *possibly unbeknownst to the public


If the algorithm becomes insecure and the public knows about it, I remove that signature from my zone.

If the algorithm because insecure and I don't know about it, I am at the same risk as if my private key was compromised and I don't know about it.

Again, this seems like it could only be marginally useful relative to good signing practices.

--Paul Hoffman