Re: SV: Re: Coding of national characters?

[pgut001@xxxxxxxxxxxxxxxxx (Peter Gutmann)]

>It looks to me that BMPString is actually defined in the later version
>of the ASN.1 specification (ISO/IEC 8824) as a subset of UniversalString
>(with a different tag!). I have only the 88 version so I haven't been able
>to check this. Does that mean that BMPString can replace UniversalString
>wherever it appears (e.g. the DirectoryString definition of X.520)?
 
The (rather complex) issues surrounding this are explained in the X.509 style 
guide (with some recent updates to cover character set issues), available from 
http://www.cs.auckland.ac.nz/~pgut001/x509guide.txt.  Apologies to people who 
already know about the guide, but these sorts of questions seem to come up a 
fair bit so I've cc'd the message back to the list in case anyone else wants 
to know how to handle character set issues.

I've also written some code which should be able to take virtually any input 
text and convert it to an X.509-kosher form, if anyone wants to test this 
(especially with multibyte and widechar character sets) please let me know - 
I've only really got access to ASCII and 8859-1 environments so some of the 
stuff is guesswork.
 
Peter.