[Cryptography] [FORGED] Re: Is ASN.1 still the thing?

[Erwann ABALEA]

Le mer. 15 nov. 2017 à 06:20, Nico Williams <nico at cryptonector.com> a
écrit :

> On Wed, Nov 15, 2017 at 09:27:04AM +0800, Chu Ka-cheong wrote:
> > When protobuf first released, it's main feature is the
> > interoperability between different iterations of the same protocol.
> >
> > Consider you have a message like this at the beginning?
> >
> > struct People {
> >   name: String
> >   address: String
> > }
> >
> > With ASN.1 you would probably encode it as a SEQUENCE. However, how
> > would you specify it if you know you will likely add new fields to it
> > in a V2 release maybe a week later?
>
> By using extensibility markers.  Which Protocol Buffers.. does not have.
>
>   People ::= SEQUENCE {
>     name UTF8String,
>     address UTF8String,
>     ...
>   }
>

Correct. Or by declaring the module as EXTENSIBILITY IMPLIED, or simply by
using BER/DER (where extensibility is implied in the deciding phase even if
the module doesn't declare it).

-- 
Erwann.
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