draft-ietf-cbor-date-tag-02.txt   draft-ietf-cbor-date-tag-03.txt 
CBOR Working Group M. Jones CBOR Working Group M. Jones
Internet-Draft A. Nadalin Internet-Draft A. Nadalin
Intended status: Standards Track Microsoft Intended status: Standards Track Microsoft
Expires: January 1, 2021 J. Richter Expires: January 2, 2021 J. Richter
pdv Financial Software GmbH pdv Financial Software GmbH
June 30, 2020 July 1, 2020
Concise Binary Object Representation (CBOR) Tags for Date Concise Binary Object Representation (CBOR) Tags for Date
draft-ietf-cbor-date-tag-02 draft-ietf-cbor-date-tag-03
Abstract Abstract
The Concise Binary Object Representation (CBOR, RFC 7049) is a data The Concise Binary Object Representation (CBOR, RFC 7049) is a data
format whose design goals include the possibility of extremely small format whose design goals include the possibility of extremely small
code size, fairly small message size, and extensibility without the code size, fairly small message size, and extensibility without the
need for version negotiation. need for version negotiation.
In CBOR, one point of extensibility is the definition of CBOR tags. 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 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, string) and tag 1 (Posix "seconds since the epoch"). Since then,
additional requirements have become known. This specification additional requirements have become known. This specification
defines a CBOR tag for an RFC 3339 date text string, for applications defines a CBOR tag for an RFC 3339 date text string, for applications
needing a textual date representation without a time. It also needing a textual date representation without a time. It also
defines a CBOR tag for days since the Posix epoch, for applications defines a CBOR tag for days since the Posix epoch, for applications
needing a numeric date representation without a time. It is intended needing a numeric date representation without a time. These tags are
as the reference document for the IANA registration of the CBOR tags both for representations of calendar dates. It is intended as the
reference document for the IANA registration of the CBOR tags
defined. defined.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 1, 2021. This Internet-Draft will expire on January 2, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 28 skipping to change at page 2, line 28
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Notation and Conventions . . . . . . . . . . 3 1.1. Requirements Notation and Conventions . . . . . . . . . . 3
2. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 2. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
2.1. Concise Binary Object Representation (CBOR) Tags 2.1. Concise Binary Object Representation (CBOR) Tags
Registrations . . . . . . . . . . . . . . . . . . . . . . 3 Registrations . . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . 3
4. References . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Normative References . . . . . . . . . . . . . . . . . . 4 4.1. Normative References . . . . . . . . . . . . . . . . . . 4
4.2. Informative References . . . . . . . . . . . . . . . . . 4 4.2. Informative References . . . . . . . . . . . . . . . . . 4
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 4 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 4
Document History . . . . . . . . . . . . . . . . . . . . . . . . 4 Document History . . . . . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
The Concise Binary Object Representation (CBOR) [RFC7049] provides The Concise Binary Object Representation (CBOR) [RFC7049] provides
for the interchange of structured data without a requirement for a for the interchange of structured data without a requirement for a
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This specification also defines a CBOR tag for an integer This specification also defines a CBOR tag for an integer
representing a date without a time. The tagged integer is an representing a date without a time. The tagged integer is an
unsigned or negative value indicating the number of days since the unsigned or negative value indicating the number of days since the
IEEE Std 1003.1, 2013 Edition [POSIX.1] epoch date 1970-01-01. As an IEEE Std 1003.1, 2013 Edition [POSIX.1] epoch date 1970-01-01. As an
implementation note, this value has a constant offset from the implementation note, this value has a constant offset from the
Modified Julian Date value (which is defined by the Smithsonian Modified Julian Date value (which is defined by the Smithsonian
Astrophysical Observatory as the number of days since November 17, Astrophysical Observatory as the number of days since November 17,
1858); this value is the Modified Julian Date minus 40,587. 1858); this value is the Modified Julian Date minus 40,587.
Note that since both tags are for dates without times, time zones and Note that since both tags are for dates without times, time zones and
leap seconds are not applicable to these values. leap seconds are not applicable to these values. These tags are both
for representations of calendar dates.
1.1. Requirements Notation and Conventions 1.1. Requirements Notation and Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
2. IANA Considerations 2. IANA Considerations
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o Semantics: Number of days since the epoch date 1970-01-01 o Semantics: Number of days since the epoch date 1970-01-01
o Reference: [[ this specification ]] o Reference: [[ this specification ]]
3. Security Considerations 3. Security Considerations
The security considerations of RFC 7049 apply; the tags introduced The security considerations of RFC 7049 apply; the tags introduced
here are not expected to raise security considerations beyond those. here are not expected to raise security considerations beyond those.
A date, of course, has significant security considerations; these A date, of course, has significant security considerations; these
include the exploitation of ambiguities where the date is security include the exploitation of ambiguities where the date is security
relevant or where the date is used in access control decisions. relevant or where the date is used in access control decisions. When
However, typically times will also be used when making access control using a calendar date for decision making, for example access
decisions, rather than dates without times. control, it needs to be noted that since calendar dates do not
represent a specific point in time, the results of the evaluation can
differ depending upon where the decision is made. For instance, a
person may have reached their 21st birthday in Japan while
simultaneously being a day short of their 21st birthday in Hawaii.
4. References 4. References
4.1. Normative References 4.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>. <https://www.rfc-editor.org/info/rfc3339>.
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IEEE Std 1003.1, 2013 Edition, 2013, IEEE Std 1003.1, 2013 Edition, 2013,
<http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/ <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/
V1_chap04.html#tag_04_15>. V1_chap04.html#tag_04_15>.
Acknowledgements Acknowledgements
Thanks to Carsten Bormann for supporting creation of this Thanks to Carsten Bormann for supporting creation of this
specification. Parts of the explanatory text in this specification specification. Parts of the explanatory text in this specification
come from draft-bormann-cbor-time-tag-02. come from draft-bormann-cbor-time-tag-02.
Thanks to these people for reviews of the specification: Carsten Thanks to these people for reviews of the specification: Henk
Bormann, Jim Schaad, and Dale Worley. Birkholz, Carsten Bormann, Thiago Macieira, Michael Richardson, Jim
Schaad, Juergen Schoenwaelder, and Dale Worley.
Document History Document History
[[ to be removed by the RFC Editor before publication as an RFC ]] [[ to be removed by the RFC Editor before publication as an RFC ]]
-03
o Added statement that these tags are both for representations of
calendar dates.
o Described consequences of using calendar dates in access control
decisions.
-02 -02
o Addressed working group last call comments, including stating that o Addressed working group last call comments, including stating that
time zones are not applicable to these values. time zones are not applicable to these values.
-01 -01
o Changed "positive or negative" to "unsigned or negative". o Changed "positive or negative" to "unsigned or negative".
o Added an implementation note about the relationship to Modified o Added an implementation note about the relationship to Modified
 End of changes. 11 change blocks. 
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