BinaryTime: An Alternate Format for Representing Date and Time in ASN.1
RFC 6019
Document | Type |
RFC - Proposed Standard
(September 2010; No errata)
Obsoletes RFC 4049
|
|
---|---|---|---|
Author | Russ Housley | ||
Last updated | 2013-03-02 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 6019 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) R. Housley Request for Comments: 6019 Vigil Security Obsoletes: 4049 September 2010 Category: Standards Track ISSN: 2070-1721 BinaryTime: An Alternate Format for Representing Date and Time in ASN.1 Abstract This document specifies a new ASN.1 type for representing time: BinaryTime. This document also specifies an alternate to the signing-time attribute for use with the Cryptographic Message Syntax (CMS) SignedData and AuthenticatedData content types; the binary- signing-time attribute uses BinaryTime. CMS and the signing-time attribute are defined in RFC 5652. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6019. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Housley Standards Track [Page 1] RFC 6019 BinaryTime September 2010 1. Introduction This document specifies a new ASN.1 [ASN1] type for representing time: BinaryTime. This ASN.1 type can be used to represent date and time values. This document also specifies an alternative to the signing-time attribute used with the Cryptographic Message Syntax [CMS] SignedData and AuthenticatedData content types, allowing the BinaryTime type to be used instead of the traditional UTCTime and GeneralizedTime types. 1.1. BinaryTime Many operating systems represent date and time as an integer. This document specifies an ASN.1 type for representing date and time in a manner that is also an integer. Although some conversion may be necessary due to the selection of a different epoch or a different granularity, an integer representation has several advantages over the UTCTime and GeneralizedTime types. First, a BinaryTime value is smaller than either a UTCTime or a GeneralizedTime value. Second, in some operating systems, the value can be used with little or no conversion. Conversion, when it is needed, requires only straightforward computation. If the endian ordering is different from the ASN.1 representation of an INTEGER, then straightforward manipulation is needed to obtain an equivalent integer value. If the epoch is different than the one chosen for BinaryTime, addition or subtraction is needed to compensate. If the granularity is something other than seconds, then multiplication or division is needed to compensate. Also, padding may be needed to convert the variable- length ASN.1 encoding of INTEGER to a fixed-length value used in the operating system. Third, date comparison is very easy with BinaryTime. Integer comparison is easy, even when multi-precision integers are involved. Date comparison with UTCTime or GeneralizedTime can be complex when the two values to be compared are provided in different time zones. This is a rare instance in which both memory and processor cycles can be saved. 1.2. Binary Signing Time Attribute The signing-time attribute is defined in [CMS]. The alternative binary-signing-time attribute is defined in this document in order to obtain the benefits of the BinaryTime type. Housley Standards Track [Page 2] RFC 6019 BinaryTime September 2010 1.3. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [STDWORDS]. 2. BinaryTime Definition The BinaryTime ASN.1 type is used to represent an absolute time and date. A positive integer value is used to represent time valuesShow full document text