Re: GeneralString, UniversalString, or UTF8String?

[Nikos Mavrogiannopoulos]

On 09/21/2012 10:15 AM, Ivan Shmakov wrote:

>       I'm writing an application which has to support the full range
>       of Unicode characters being stored to and retrieved from its
>       (structured) data files, which are to be binary for both space
>       and performance reasons.
>       Although my experience with ASN.1 is limited, it seems like a
>       suitable base format for such an application.  As per [1], my
>       guess is that I should use either UniversalString or UTF8String
>       to store Unicode text strings (though I don't understand the
>       difference.)  However, as per [2], the only character sequence
>       type currently supported by GNU Libtasn1 is GeneralString.


We use UTF8String and UniversalString with libtasn1 in gnutls by
defining it as:
UTF8String ::= [UNIVERSAL 12] IMPLICIT OCTET STRING
UniversalString ::= [UNIVERSAL 28] IMPLICIT OCTET STRING

Of course there is no checking on whether the contents of these fields
conform to any standards. They are treated as opaque.

regards,
Nikos