RE: ASN.1 types for Distinguished names (was: Re: Distinguished n ames and

[Andrew Probert <[e-mail]>]

Further to my previous email, here is a comment from Microsoft:

<snip>
We have UNICODE X.509 Name ASN.1 encode/decode routines. When converting
UNICODE to a T61String we convert to UTF8. The UTF8 represents the
characters 0 .. 0x7f as a single byte, 0x80 .. 0x7ff as two bytes, and
0x800 ..0xffff as three bytes. UTF8 is also being used by Java.

<snip>

> -----Original Message-----
> From:	Brian Korver [SMTP:[e-mail]]
> Sent:	Thursday, April 03, 1997 3:32 AM
> To:	[e-mail]
> Cc:	[e-mail]; [e-mail]
> Subject:	Re: ASN.1 types for Distinguished names (was: Re:
> Distinguished names and
> 
> 
> Holger Reif writes:
> > 
> > Hi,
> > 
> > this seems to be a nice thread to jump in ;-)
> > 
> > I noticed that many of the X.520 Selected attributes are of type
> DirectoryString
> > which in turn is a choice of teletexString, printableString and
> universalString.
> > Does anybody know when which Form is to be used and wether a
> transformation 
> > between these types (if possible) is allowed and gives equal
> meaning. 
> 
> BMPString has basically replaced UniversalString because, I have
> been told, nobody used UniversalString.  I can be believe this.
> 
> Both TeletexString (T61String) and PrintableString have constraints as
> to what can be placed in them.  So for instance if you need to use a
> character such as '@', you cannot use PrintableString.
> 
> I'm unaware of any equality rules to use when comparing strings of 
> unequal type.  I assume that most implementations assume that strings
> of unequal type are by definition not equal.  IMHO this is the best
> approach because of the lack of well-defined equality matching rules.
> 
> I'm also unaware of any rules for "which string do I use" when there
> are multiple string types to choose from.
> 
> 
> > Of course, if it's within a SIGNED context then the answer is clear:
> 
> > one can't change the types. But in other cases?
> 
> brian
> [e-mail]