Re: draft-yoon-pkix-wireless-internet-00.txt

[Eric Rescorla <ekr@xxxxxxxx>]

"Housley, Russ" <rhousley@xxxxxxxxxxxxxxx> writes:
> You said:
> >We had to consider the size of ASN.1 run-time library and its actual code 
> >size and processing time including key generation in mobile devices. We 
> >just have maximum 150Kbyte in a brand-new mobile phone. And it was nearly 
> >impossible to make a partial revision of commercial ASN.1 product without 
> >manufacturer’s (OSS etc.) assistance. So we tested not an ASN.1 but 
> >different methods again and again. Fortunately, we ported the PKI 
> >application at mobile devices and have finished testing it. Now, We are 
> >ready to launch the service.
> 
> I have experience with ASN.1 data structures limited processing 
> environments, specifically smart cards.  In this environment, we did could 
> not use a general purpose toolkit for the reasons that you discuss 
> above.  However, we found that there were very few ASN.1 data structures 
> that actually needed to be processed in the limited processing 
> environment.  In some cases, only decoders were needed.  In other case, 
> only encoders were needed.  In very few cases, both encoders and decoders 
> were needed.  Therefore, we simply wrote code for the structures that we 
> cared about.  The resulting structure-specific code was very small, and it 
> had no burdensome run-time requirements (like large tables).  It appears to 
> me that similar code could be used to implement the ASN.1 structures that 
> your draft proposes to eliminate.
I've got to agree with Russ here. Writing a generalized ASN.1 parser
is quite a bit of work. Writing a primitive decoder for a few specific
data structures is straightforward (though tedious) and can be 
executed within quite a small footprint.

-Ekr


-- 
[Eric Rescorla                                   ekr@xxxxxxxx]
                http://www.rtfm.com/