[cabfpub] Private key control

Bruce Morton bruce.morton at entrust.com
Fri Oct 24 14:19:25 UTC 2014

I think the requirement should be dropped.

If we only validate the signature on the CSR, then we do not know if there is a man-in-the-middle. You need some other data.

If we want to technically validate private key control, then we should take some action such as sending the Subscriber some information out-of-band for signature. The signature would be compared to the signature on the CSR to see if the same key was used.

The softer way that an OV/EV private key control is confirmed is by contacting the Subscriber out of band to confirm that they made/authenticate the request. I don't think this works for DV. It will also not work when the Subscriber can approve a certificate issuance with dual-factor login.

I don't think we should have the requirement unless we suggest methods that will actually work for all certificate types and our current certificate management methods.

This requirement is not in the BRs or the EV guidelines and we have not been suffering from an incidents, so again, I think the requirement should be dropped.


From: public-bounces at cabforum.org [mailto:public-bounces at cabforum.org] On Behalf Of Rick Andrews
Sent: Thursday, October 23, 2014 2:46 PM
To: Jeremy Rowley; CABFPub
Subject: Re: [cabfpub] Private key control


How about "The CA MAY verify this association by obtaining a CSR from the Applicant and validating the signature on the CSR."


From: public-bounces at cabforum.org<mailto:public-bounces at cabforum.org> [mailto:public-bounces at cabforum.org] On Behalf Of Jeremy Rowley
Sent: Wednesday, October 22, 2014 6:57 PM
Subject: [cabfpub] Private key control

During the Code Signing BR discussion a few weeks ago, we noticed that the Baseline Requirements lack a definitive requirement for the CA to confirm that the Application is properly associated with the Public Key being included in the certificate.  We'd like to remedy this oversight.  What does everyone thing about adding a section similar to the following to the BRs?
Section 11.1.5    Verification of Key Pair Association
Prior to issuing a Certificate, the CA MUST verify that the Applicant's Private Key is properly associated with the Public Key and a subject name to be included in the Certificate. The CA MAY verify this association by obtaining a CSR from the Applicant.

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