[cabf_validation] [EXTERNAL]Re: Ballot Proposal: Validation Method in certificatePolicies

[Corey Bonnell]

Hi Wayne,
Perhaps create another extension/OID to contain the BIT STRING of validation methods for IP addresses? Doing so would remove the need to have a special numbering scheme for IP address validation method numbers and would be straightforward to process.

Additionally, if a certificate contains only iPAddress SANs, it could omit the dNSName-specific extension entirely (likewise for a certificate that contains only dNSNames). Certificates that contain both dNSNames and iPAddress SANs are rare in practice, so there is no additional space overhead in the common case.

Thanks,
Corey


Corey Bonnell
Senior Software Engineer

Trustwave | SMART SECURITY ON DEMAND
https://www.trustwave.com<http://www.trustwave.com/>

From: Validation <validation-bounces at cabforum.org> on behalf of Wayne Thayer via Validation <validation at cabforum.org>
Reply-To: Wayne Thayer <wthayer at mozilla.com>, CA/Browser Forum Validation WG List <validation at cabforum.org>
Date: Wednesday, August 15, 2018 at 12:34 PM
To: Tim Hollebeek <tim.hollebeek at digicert.com>, CA/Browser Forum Validation WG List <validation at cabforum.org>
Subject: Re: [cabf_validation] [EXTERNAL]Re: Ballot Proposal: Validation Method in certificatePolicies

To make the BIT STRING encoding work in a single extension, we should discuss how best to collapse domain and IP address validation methods into a single "namespace". It might be best to add explicit and unique numbering to all the domain + IP address methods as part of the ballot to remove the IP address "any other method". I'd like to avoid the need for a separate mapping table (e.g. bit position 17 signifies method 3.2.2.5.3).

On Wed, Aug 15, 2018 at 9:22 AM Tim Hollebeek via Validation <validation at cabforum.org<mailto:validation at cabforum.org>> wrote:
Yeah, lots of people are going to make the same mistake I did if Method 6 is represented by bit 5 (not 6!  I like my bit numbers to be zero based, so you can just do the power thing).  Off by one errors are so much fun …

But again, I don’t think it’s a huge problem.  Only technical people are staring at this stuff, and they’ll quickly learn which values correspond to which methods.

-Tim

From: Ryan Sleevi <sleevi at google.com<mailto:sleevi at google.com>>
Sent: Wednesday, August 15, 2018 11:32 AM
To: Tim Hollebeek <tim.hollebeek at digicert.com<mailto:tim.hollebeek at digicert.com>>
Cc: Doug Beattie <doug.beattie at globalsign.com<mailto:doug.beattie at globalsign.com>>; Daymion T. Reynolds <dreynolds at godaddy.com<mailto:dreynolds at godaddy.com>>; CA/Browser Forum Validation WG List <validation at cabforum.org<mailto:validation at cabforum.org>>
Subject: Re: [cabf_validation] [EXTERNAL]Re: Ballot Proposal: Validation Method in certificatePolicies


On Wed, Aug 15, 2018 at 9:24 AM Tim Hollebeek <tim.hollebeek at digicert.com<mailto:tim.hollebeek at digicert.com>> wrote:
Given that the number of 1 bits is likely low, I don’t think BIT STRING is that hard to read.  It just means that you’re going to have to memorize that Method 6 is “64” instead of 6.  It’s slightly tougher, but if you’re the sort of person who is capable of staring at raw ASN.1, I think you can cope.

I'm not sure I understand your point about knowing that "Method 6 is 64".

Method 6 is Bit 6.
Method 7 is Bit 7.
Method 139 is Bit 139.

A certificate viewer that does not dive into constructed extensions would display the extension as its full hex (e.g. with the outer Tag and Length octets).
A certificate viewer that does dive into constructed extensions would display the inner value, typically in either base2 or base16 notation. In Base2 notation, it's 'easy' to count which bits are set. In Base16 notation, you can easily convert to Base2.
A certificate viewer that explicitly knows about this extension can:
  - Used named values for methods it recognizes - e.g. as a lookup table, same as OIDs)
  - Alternatively, note the integer position itself for which bit was set - e.g. bit 1 = method 1, bit 2 = method 2 etc. - and display that as such

But regardless, you shouldn't expect to see "Method 6 is 64". You'd expect 32, at best, but more realistically, 0x20. :)

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