<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Many organizations have policies to not re-use keys between certificates. Dropping the validity period therefore effectively drops the key usage period.</div><br class=""><div><blockquote type="cite" class=""><div class="">On Feb 21, 2017, at 10:54 AM, Ryan Sleevi via Public <<a href="mailto:public@cabforum.org" class="">public@cabforum.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div dir="ltr" class="">This doesn't seem particularly relevant - I haven't heard any suggestion that this is about ensuring frequent key rotation, as opposed to all the other policies and practices being attested to in conjunction with the keys.<br class=""><div class="gmail_extra"><br class=""><div class="gmail_quote">On Tue, Feb 21, 2017 at 10:52 AM, Dean Coclin via Public <span dir="ltr" class=""><<a href="mailto:public@cabforum.org" target="_blank" class="">public@cabforum.org</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="EN-US" link="#0563C1" vlink="#954F72" class="">
<div class="m_7917516592352108161WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="">Posting on behalf of AT&T:<u class=""></u><u class=""></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class=""><u class=""></u> <u class=""></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Arial",sans-serif;color:blue" class="">AT&T typically looks to NIST for guidance and reference on industry standards, see page 45 of the attached (NIST SP800-57-Pt1R4) document.</span></p></div></div></blockquote></div></div></div></div></blockquote></div></body></html>