[cabfpub] New Google policy on SHA-1 deprecation next 6-112 weeks

Tim Shirley TShirley at trustwave.com
Fri Aug 22 10:03:37 MST 2014

Can we clarify if the date checks apply only to the end-entity certificates?  Or do they also apply to the intermediates?  If the latter, that would require new SHA-1 intermediates to be issued with 2015-12-31 expiration dates in order to offer option #1 to customers.

From: public-bounces at cabforum.org [mailto:public-bounces at cabforum.org] On Behalf Of kirk_hall at trendmicro.com
Sent: Friday, August 22, 2014 12:15 PM
To: CABFPub (public at cabforum.org)
Subject: [cabfpub] New Google policy on SHA-1 deprecation next 6-112 weeks

For those CA/Browser Forum members who were not on the Forum conference call yesterday, I wanted to forward information that Google disclosed during the call that will affect all CAs.

Google has announced a policy to deprecate many SHA-1 certificates and some SHA-256 certificated currently in use in the next 6-12 weeks (upon the release of Chrome version 39):


Here is how we understand this.

Starting with Chrome 39, in about 12 weeks (mid-November), when Chrome encounters an SSL certificate that is SHA-1, or a SHA-256 certificate with a SHA-1 intermediate in the chain, the user will see a deprecated security UI.  Specifically:

·         If the SSL cert expires after 1/1/2016 but before 2017, then the user will see a padlock with a red line though it (and no green bar for EV certificates) and the page will be served up as normal with no user action.

·         If the SSL certificate expires after 1/1/2017, then the user will see the padlock with a red line through it, AND the page will be treated as mixed content and the user will need to perform an action to proceed.

·         Again, this will affect all SHA-1 certificates and all SHA-256 certificates issued from a SHA-1 intermediate certificate, no matter when such certificates were issued or deployed.

·         Per Google, SHA-1 roots can still be used, but all certificates in the chain must be SHA-256 to avoid the negative UI.

Google has told CAs that their affected customers have two choices over the next 6-12 weeks to avoid the negative UIs for their websites.

·         Customers can replace their SHA-1 certs that expire in 2016 or 2017 with new SHA-1 certs that expire no later than 12/31/2015 (same for new  SHA-256 certs issued from a SHA-1 intermediate), and they will get the regular UI trust symbols in Chrome, or

·         Customers can replace their SHA-1 certs (or SHA-256 certs issued from a SHA-1 intermediate) with SHA-256 certs issued from SHA-256 intermediates, which can expire in 2016 or 2017 and will receive the regular UI trust symbols in Chrome.

Kirk R. Hall
Operations Director, Trust Services
Trend Micro


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