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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>Hi Bruce,<o:p></o:p></p><p class=MsoNormal>I agree that using the invalidityDate CRL entry extension to express when the key corresponding to a revoked code signing certificate can no longer be trusted as opposed to the revocation date is conceptually cleaner and more in line with 5280 (which states that the revocation date SHOULD NOT be backdated such that it is before the issue date of the latest CRL). <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>However, in all the documentation I’ve seen regarding Authenticode, it appears that the revocation date is the value that is checked by Windows and invalidityDate is seemingly not used.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Could Ian or Mike confirm Windows’s behavior in this regard?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal>Corey<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b>From:</b> Cscwg-public <cscwg-public-bounces@cabforum.org> <b>On Behalf Of </b>Bruce Morton via Cscwg-public<br><b>Sent:</b> Wednesday, August 25, 2021 1:59 PM<br><b>To:</b> cscwg-public@cabforum.org<br><b>Subject:</b> [Cscwg-public] Invalidity Date<o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>CSBR 13.2.1 states: A Certificate MAY have a one-to-one relationship or one-to-many relationship with the signed Code. Regardless, revocation of a Certificate may invalidate the Code Signatures on all signed Code, some of which could be perfectly sound. Because of this, <span style='background:yellow;mso-highlight:yellow'>the CA MAY specify a revocation date in a CRL</span> or OCSP response to time-bind the set of software affected by the revocation, and software should continue to treat objects containing a timestamp dated before the revocation date as valid.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The CSBRs are referring to “revocation date’, which I believe should be referring to “invalidity date” as specified in RFC 5280, <a href="https://datatracker.ietf.org/doc/html/rfc5280#section-5.3.2">https://datatracker.ietf.org/doc/html/rfc5280#section-5.3.2</a>.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Note that we need to think of the following dates:<o:p></o:p></p><ul style='margin-top:0cm' type=disc><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level1 lfo3'>Valid from<o:p></o:p></li><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level1 lfo3'>Invalidity date<o:p></o:p></li><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level1 lfo3'>Revocation date<o:p></o:p></li><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level1 lfo3'>Valid to<o:p></o:p></li></ul><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The purpose of the Invalidity date is to provide a date in the past, when the key was compromised. The revocation date would be on the date that the certificate was revoked and cannot be a past date.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Would there be any objections in changing “revocation date” to “invalidity date” in a future ballot? <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks, Bruce<o:p></o:p></p><p class=MsoNormal><i>Any email and files/attachments transmitted with it are confidential and are intended solely for the use of the individual or entity to whom they are addressed. If this message has been sent to you in error, you must not copy, distribute or disclose of the information it contains. <u>Please notify Entrust immediately</u> and delete the message from your system.</i> <o:p></o:p></p></div></body></html>