[cabfpub] [Cscwg-public] [EXTERNAL] Re: Code signing and Time stamping

Thu Apr 29 09:07:44 UTC 2021

Could it be argued, at least conceptually, that there should be a separate CABForum working group dedicated entirely to Time Stamping?  After all, the Code Signing ecosystem doesn't have a monopoly on Time Stamping.  For example, Adobe software uses Time Stamping in the context of Document Signing.  If Adobe wanted to collaborate with CABForum members on Time Stamping certificate profiles, what (assuming Adobe had no interest in Code Signing) would be the best venue for that?

(Please note: I'm not advocating any position here; I'm just thinking aloud).

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From: Cscwg-public <cscwg-public-bounces at cabforum.org> on behalf of Bruce Morton via Cscwg-public <cscwg-public at cabforum.org>
Sent: 26 April 2021 14:18
To: Ben Wilson <bwilson at mozilla.com>; cscwg-public at cabforum.org <cscwg-public at cabforum.org>; Dean Coclin <dean.coclin at digicert.com>; CA/Browser Forum Public Discussion List <public at cabforum.org>
Subject: Re: [Cscwg-public] [EXTERNAL] Re: [cabfpub] Code signing and Time stamping

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To follow up, the CSCWG charter includes the following documents:

a. EV Code Signing Guidelines, v. 1.4 and subsequent versions

b. Version 1.0 Draft of November 19, 2015, Baseline Requirements for the Issuance and Management of Publicly-Trusted Code Signing Certificates (subject to the CSCWG making a written finding that the provenance of such document is sufficiently covered by the Forum’s IPR Policy)

The documents define requirements or reference: timestamp authority (TSA), timestamps, timestamp implementation method, timestamp certificate, timestamp signed objects, TSA logging, and timestamp key protection. The documents also define the certificate profiles for timestamp root, timestamp subordinate CA and timestamp authority. As such, the CSCWG has considered it is in scope to manage these documents and the requirements associated to allow timestamp signatures with code signed using certificates conforming to the CSBRs.

The CSBRs also state, “CAs complying with these Requirements MAY also assert the reserved policy OIDs in such Certificates.” The reserved policy OIDs reference those required for Non-EV and EV code signing certificates. The CSBRs do not reference an OID for a timestamp certificate, since the OID has not been reserved. It is also considered appropriate to use all applicable reserved certificate policy OIDs as we consider deploying dedicated PKI hierarchies to support code signing.

As such, the CSCWG plans to add the following reserved certificate policy OID to the CSBRs, which may be included in a timestamp certificate, which meets the requirements of the CSBRs:

{joint-iso-itu-t(2) international-organizations(23) ca-browser-forum(140) certificate-policies(1) code-signing-requirements(4) timestamping(2)} (2.23.140.1.4.2)

Bruce.

From: Cscwg-public <cscwg-public-bounces at cabforum.org> On Behalf Of Ben Wilson via Cscwg-public
Sent: Tuesday, April 20, 2021 12:09 PM
To: Dean Coclin <dean.coclin at digicert.com>; CA/Browser Forum Public Discussion List <public at cabforum.org>
Cc: cscwg-public at cabforum.org
Subject: [EXTERNAL] Re: [Cscwg-public] [cabfpub] Code signing and Time stamping

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Just a few thoughts to move this conversation forward, and speaking as a CSCWG interested party and not to advocate any position of Mozilla, I think the answer depends on how strict or flexible the CABF wants to be as an organization when it comes to interpreting the scope of a working group charter.

It seems that the mention of time stamping in a code signing work product would be allowed even under a strict interpretation.  While creating standards for issuing and managing time stamping certificates would certainly be out of scope with a flexible interpretation.

The Scope in the Charter does not expressly include or exclude the assignment of a time stamping OID for time stamping certificates.

https://cabforum.org/2019/03/26/code-signing-certificate-wg-charter/#1-Scope<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Furldefense.com%2Fv3%2F__https%3A%2Fcabforum.org%2F2019%2F03%2F26%2Fcode-signing-certificate-wg-charter%2F*1-Scope__%3BIw!!FJ-Y8qCqXTj2!KO_2DRjCLlG3XphTaFOKt3DIbyewuzdXb3w04DZftMjNQ74YZEHuLmO13bB-Y764wXA%24&data=04%7C01%7C%7C427335acc5eb4722c34408d908b5c6ea%7C0e9c48946caa465d96604b6968b49fb7%7C0%7C0%7C637550399087360682%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=On%2FYLtGShUwaWS%2FOYXT0aqM7HYc7PBpRLxglLEMhWN0%3D&reserved=0>

Included in the scope is "Version 1.0 Draft of November 19, 2015, Baseline Requirements for the Issuance and Management of Publicly-Trusted Code Signing Certificates (subject to the CSCWG making a written finding that the provenance of such document is sufficiently covered by the Forum’s IPR Policy)."  Time stamping was discussed in that draft, and I recall that the CSCWG did make the required written finding of provenance.  Is the assignment of a timestamping OID a logical outcome of the continued work on that earlier document?

Ben

On Mon, Apr 19, 2021 at 2:31 PM Dean Coclin via Public <public at cabforum.org<mailto:public at cabforum.org>> wrote:

A discussion on last week’s CA/B call about code signing and time stamping brought up a question as to whether the latter was in scope of the CSCWG charter (https://cabforum.org/2019/03/26/code-signing-certificate-wg-charter/<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Furldefense.com%2Fv3%2F__https%3A%2Fcabforum.org%2F2019%2F03%2F26%2Fcode-signing-certificate-wg-charter%2F__%3B!!FJ-Y8qCqXTj2!KO_2DRjCLlG3XphTaFOKt3DIbyewuzdXb3w04DZftMjNQ74YZEHuLmO13bB-wNVdJJQ%24&data=04%7C01%7C%7C427335acc5eb4722c34408d908b5c6ea%7C0e9c48946caa465d96604b6968b49fb7%7C0%7C0%7C637550399087370641%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=hife2VbpDtPAJlkwyMrVvFS%2Btf3CL78iZCa7Ah6iACk%3D&reserved=0>).

Bruce said there was no CP OID for time stamping and that the group wanted to create one IAW with the CA/B Forum registry. Ryan was concerned that this was outside the CSCWG charter as it was not specifically mentioned therein. Dimitris commented that it was included in charter scope 1a which pulls in the EV CS guidelines where time stamping is specified. Ryan did not seem convinced and asked that the discussion continue on the list.

The working group has not had a chance to discuss this since the Forum meeting but plans to do so on the next call.

I’ve included the CS Public list on this thread since the topic is of interest to members/observers there. If a respondent does not have posting rights, I can re-post for them.

Dean

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