Internet DRAFT - draft-jones-cbor-date-tag
draft-jones-cbor-date-tag
CBOR Working Group M. Jones
Internet-Draft A. Nadalin
Intended status: Standards Track Microsoft
Expires: October 23, 2020 J. Richter
pdv Financial Software GmbH
April 21, 2020
Concise Binary Object Representation (CBOR) Tags for Date
draft-jones-cbor-date-tag-01
Abstract
The Concise Binary Object Representation (CBOR, RFC 7049) is a data
format whose design goals include the possibility of extremely small
code size, fairly small message size, and extensibility without the
need for version negotiation.
In CBOR, one point of extensibility is the definition of CBOR tags.
RFC 7049 defines two tags for time: CBOR tag 0 (RFC 3339 date/time
string) and tag 1 (Posix "seconds since the epoch"). Since then,
additional requirements have become known. This specification
defines a CBOR tag for an RFC 3339 date text string, for applications
needing a textual date representation without a time. It also
defines a CBOR tag for days since the Posix epoch, for applicaitons
needing a numeric date representation without a time. It is intended
as the reference document for the IANA registration of the CBOR tags
defined.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on October 23, 2020.
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Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Notation and Conventions . . . . . . . . . . 3
2. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
2.1. Concise Binary Object Representation (CBOR) Tags
Registrations . . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 3
4. References . . . . . . . . . . . . . . . . . . . . . . . . . 3
4.1. Normative References . . . . . . . . . . . . . . . . . . 3
4.2. Informative References . . . . . . . . . . . . . . . . . 4
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 4
Document History . . . . . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
The Concise Binary Object Representation (CBOR) [RFC7049] provides
for the interchange of structured data without a requirement for a
pre-agreed schema. RFC 7049 defines a basic set of data types, as
well as a tagging mechanism that enables extending the set of data
types supported via an IANA registry.
This specification defines a CBOR tag for a text string representing
a date but not a time. The tagged text string is represented as
specified by the RFC 3339 [RFC3339] "full-date" production.
This specification also defines a CBOR tag for an integer
representing a date but not a time. The tagged integer is a positive
or negative value indicating the number of days since the IEEE Std
1003.1, 2013 Edition [POSIX.1] epoch date 1970-01-01.
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1.1. Requirements Notation and Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. IANA Considerations
2.1. Concise Binary Object Representation (CBOR) Tags Registrations
This section registers the following values in the IANA "Concise
Binary Object Representation (CBOR) Tags" registry [IANA.cbor-tags].
o Tag: 1004 (value requested)
o Data Item: UTF-8 text string
o Semantics: RFC 3339 full-date string
o Reference: [[ this specification ]]
o Tag: 100 (ASCII 'd') (value requested)
o Data Item: Positive or negative integer
o Semantics: Number of days since the epoch date 1970-01-01
o Reference: [[ this specification ]]
3. Security Considerations
The security considerations of RFC 7049 apply; the tags introduced
here are not expected to raise security considerations beyond those.
A date, of course, has significant security considerations; these
include the exploitation of ambiguities where the date is security
relevant or where the date is used in access control decisions.
4. References
4.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
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[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
4.2. Informative References
[IANA.cbor-tags]
IANA, "Concise Binary Object Representation (CBOR) Tags",
<http://www.iana.org/assignments/cbor-tags>.
[POSIX.1] IEEE, "The Open Group Base Specifications Issue 7",
IEEE Std 1003.1, 2013 Edition, 2013,
<http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/
V1_chap04.html#tag_04_15>.
Acknowledgements
Thanks to Carsten Bormann for supporting creation of this
specification. Parts of the explanatory text in this specification
come from draft-bormann-cbor-time-tag-02.
Document History
[[ to be removed by the RFC Editor before publication as an RFC ]]
-01
o Added tag for numeric date values relative to the Posix Epoch that
was proposed by Joerg Richter.
-00
o Initial version.
Authors' Addresses
Michael B. Jones
Microsoft
Email: mbj@microsoft.com
URI: https://self-issued.info/
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Anthony Nadalin
Microsoft
Email: tonynad@microsoft.com
Joerg Richter
pdv Financial Software GmbH
Email: joerg.richter@pdv-fs.de
Jones, et al. Expires October 23, 2020 [Page 5]
