[cabfpub] RFC5280

[Peter Bowen]

> On Feb 24, 2016, at 10:56 AM, Jeremy Rowley <jeremy.rowley at digicert.com> wrote:
> 
> I’ve been playing around with Peter Bowen’s certlint (an excellent tool) and, looking at the cert universe as a whole, there are some noticeable issues with the BRs and RFC 5280 that I though merited a public CAB Forum discussion.  Some of this is likely me not knowing the entire history of 5280, so I appreciated any explanation. If there’s exceptions we would like to make to RFC5280, we should probably also push a bis with IETF at the same time. 
>  
> Here’s what I’m noticing are common issues:
> 1)      Org names, common names,  and address fields are limited to 64 characters. Very few international companies can comply with this restriction. It’s even worse if you are converting an IDN to a printable string.  I don’t think any browsers limit this to 64 characters?  Is there a strong objection to permitting longer strings in these fields?
> 2)      keyAgreement isn’t specifically prohibited in the BRs or 5280. However, keyAgreement should no longer be used in ECC certs because of security issues as explained by Ryan Sleevi in previous emails . We should update the BRs to prohibit keyAgreement.

I used RFCs 5280, 6818, 3279, 5480, and 5758.  Several of these specify what key usages are acceptable with which public key types.  Are you suggesting that the other PKIX RFCs are not what CAs should be following?

> 3)      Years ago, we discussed that 2047 bit certs were equivalent to 2048 bit certs (although the discussion may have occurred solely on the Mozilla mailing list).  We should codify this exception. 
> 4)      Why is teletext string not permissible on a lot of these fields? I also don’t understand the weird requirement to use printablestring over UTRF8 for some fields. Specifically, requiring a printable string for subject:serialNumber could cause issues with the EV Guidelines if a country uses an IDN as part of their registration number.  

TeletexString (along with its friends VideotexString, GraphicString, and GeneralString) are almost impossible to get right.  They all allow ISO/IEC 2022 escape sequences and require escape sequences to use characters outside the default character.  TeletexString specifically defines the default graphics (G0) character set as T.61-7bit (102) rather than ASCII (6), which leads to interesting surprises.  For example {, }, and ^ are not allowed.

Thanks,
Peter
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