Name Constraints, was Re: [caops-wg] Re: ca signing policy file

[Mike Helm]

David Chadwick writes:
> Can anyone give me evidence of support or non-support of commercial CAs 
> for the name constraints extension?

Well, in the recent past, no commercial client software supported 
name constraints, so whether commercial CAs supported them or not
was a moot point.  Well worse than that, since it's a critical
extension.  Your CA would be useless.

openssl doesn't support it, so that makes use of name constraints
in the web &c world pretty much impossible.  I am not sure whether
recent Windows products can; it would make sense that they do,
because of cross-signing support, but I don't know.