[147459] in cryptography@c2.net mail archive
Re: [Cryptography] encoding formats should not be committee'ized
daemon@ATHENA.MIT.EDU (Viktor Dukhovni)
Wed Oct 2 11:01:52 2013
X-Original-To: cryptography@metzdowd.com
Date: Wed, 2 Oct 2013 14:46:05 +0000
From: Viktor Dukhovni <cryptography@dukhovni.org>
To: cryptography@metzdowd.com
In-Reply-To: <CAMm+LwidbKnvbk9fXj8uW7iM4ekvOWSO_6-9y48-amwcvRwd6Q@mail.gmail.com>
Reply-To: cryptography@metzdowd.com
Errors-To: cryptography-bounces+crypto.discuss=bloom-picayune.mit.edu@metzdowd.com
On Wed, Oct 02, 2013 at 09:09:05AM -0400, Phillip Hallam-Baker wrote:
> SMTP does not have nested structures or need
> them. A lot of application protocols do.
MIME: RFC 2045 - 2048, ...
A rather complex nested structure, and frankly rather more ambiguous
in practice than ASN.1. For example, what is the meaning of:
...
Conent-Transfer-Encoding: base64
Conent-Transfer-Encoding: 7-bit
...
This type of ambiguity is not possible with ASN.1. There are many
more edge cases in which the same MIME input is parsed very
differently by different implementations. There are many more
interesting cases, but I shall not bore you with them here.
> Text encodings are easy to read but very difficult to specify
> boundaries in without ambiguity.
Yes, and not just boundaries.
--
Viktor.
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