Re: DER encoding in RFC 3161

Phillip Hallam-Baker <[email protected]>
Newsgroups gmane.ietf.x509
Message-ID <CAMm+LwhdgfkbwXrfX8yiK3UDJRGOGzMJ2mXuyKqZWTdGbBE6gQ@mail.gmail.com>
I have been doing X.509v3 for 30 years now. I have yet to hear a good
answer to the question of why DER encoding is needed in PKIX.

It is a requirement of X.509 but not one that makes the slightest sense in
these days when you can store a billion certs on one disk drive and X.500
directory has fewer active users than Edison phonographs. Certificates are
moved from point A to point B as an opaque binary blob which is encoded by
the signer at signing time and only at signing time. This notion of signing
the abstract data rather than the binary bits keeps coming up but I have
yet to see anyone work out how to do it reliably, let alone add value by
doing so.

A digital signature is over a string of bits. The road to madness is paved
by canonicalization schemes.


It is sufficiently possible that there are ASN.1 parsers there that insist
on strict DER with definite length encoding throughout that changing PKIX
to allow BER encoding would now be a breaking change. And the same argument
can be made for cases where BER encoding is indicated.

So at this point, the best thing we can do is to just accept that the spec
is going to be ugly and not try to fix it.



On Tue, Jul 28, 2020 at 3:58 AM Koichi Sugimoto <koichi.sugimoto=
[email protected]> wrote:

> Hello PKIX members,
>
>
>
> RFC 3161 specifies “The eContent SHALL be the DER-encoded value of
> TSTInfo.” in “2.4.2. Response Format”
>
> Why RFC 3161 does not require DER-encoded value for full time-stamp token
> (CMS data)?
>
>
>
> On the other hand, following protocol encoding seems to require all
> DER-encoded for entire time-stamp message.
>
>
>
> 3.1. Time-Stamp Protocol Using E-mail
>
> 3.2. File Based Protocol
>
> 3.3. Socket Based Protocol
>
> 3.4. Time-Stamp Protocol via HTTP
>
>
>
> This seems time-stamp token requires DER-encoded indirectly.
>
>
>
> Regards,
>
> Koichi Sugimoto.
>
>
> _______________________________________________
> pkix mailing list
> [email protected]
> https://www.ietf.org/mailman/listinfo/pkix
>

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