Re: [Cbor] An Information-based CBOR schema language?

David Kemp <> Wed, 21 August 2019 16:59 UTC

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From: David Kemp <>
Date: Wed, 21 Aug 2019 12:57:19 -0400
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To: Carsten Bormann <>
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Subject: Re: [Cbor] An Information-based CBOR schema language?
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> Hi Carsten,

Thank you for the information and kind words; I look forward to learning
about cddl-freezer.  A script to translate JADN to JSON Schema is
surprisingly brief, about 300 lines of Python, because JSON Schema is
JSON.  I shied away from doing the same for CDDL because of the many
inconveniences of working with text, but using freezer format should make
the job much easier.

> Since the boundary between information and data models is not strict ...

Unfortunately the English language is ambiguous and easily overloaded.
Fortunately Shannon provides a more rigorous definition of information than

"My greatest concern was what to call it. I thought of calling it
> 'information,' but the word was overly used, so I decided to call it
> 'uncertainty.' When I discussed it with John von Neumann, he had a better
> idea. Von Neumann told me, 'You should call it entropy, for two reasons. In
> the first place your uncertainty function has been used in statistical
> mechanics under that name, so it already has a name. In the second place,
> and more important, no one really knows what entropy really is, so in a
> debate you will always have the advantage.'"

There may be a large gray area between information models and data models,
but there is a sharp dividing line between information and data: RFC 791
defines the information in an IPv4 address - a network with 2^32
addressable hosts can be addressed using no more than 32 bits of
information regardless of how many bits of data are used for that purpose.
JADN is more than an "Information Model" language in Webster's sense, it is
a "Model of Information" language in the Shannon sense.   I believe
modeling Shannon information is the critical key to addressing:

>  Having a single model that maps to both idiomatic JSON and concise