ASN.1 Translation
RFC 6025

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 03

Internet Engineering Task Force (IETF)                        C. Wallace
Request for Comments: 6025                            Cygnacom Solutions
Category: Informational                                      C. Gardiner
ISSN: 2070-1721                                         BBN Technologies
                                                            October 2010

                           ASN.1 Translation

Abstract

   Abstract Syntax Notation One (ASN.1) is widely used throughout the
   IETF Security Area and has been for many years.  Some specifications
   were written using a now deprecated version of ASN.1 and some were
   written using the current version of ASN.1.  Not all ASN.1 compilers
   support both older and current syntax.  This document is intended to
   provide guidance to specification authors and to implementers
   converting ASN.1 modules from one version of ASN.1 to another version
   without causing changes to the "bits on the wire".  This document
   does not provide a comprehensive tutorial of any version of ASN.1.
   Instead, it addresses ASN.1 features that are used in IETF Security
   Area specifications with a focus on items that vary with the ASN.1
   version.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   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).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see 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/rfc6025.

Wallace & Gardiner            Informational                     [Page 1]
RFC 6025                    ASN.1 Translation               October 2010

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.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  ASN.1 Design Elements  . . . . . . . . . . . . . . . . . . . .  3
     2.1.  Open Types . . . . . . . . . . . . . . . . . . . . . . . .  3
       2.1.1.  ANY DEFINED BY . . . . . . . . . . . . . . . . . . . .  4
       2.1.2.  OCTET STRINGs and BIT STRINGs  . . . . . . . . . . . .  5
       2.1.3.  Information Object Classes . . . . . . . . . . . . . .  5
     2.2.  Constraints  . . . . . . . . . . . . . . . . . . . . . . .  8
       2.2.1.  Simple Table Constraints . . . . . . . . . . . . . . .  8
       2.2.2.  Component Relation Constraints . . . . . . . . . . . .  9
       2.2.3.  Content Constraints  . . . . . . . . . . . . . . . . . 11
     2.3.  Parameterization . . . . . . . . . . . . . . . . . . . . . 12
     2.4.  Versioning and Extensibility . . . . . . . . . . . . . . . 13
       2.4.1.  Extension Markers  . . . . . . . . . . . . . . . . . . 14
       2.4.2.  Version Brackets . . . . . . . . . . . . . . . . . . . 14
   3.  Character Set Differences  . . . . . . . . . . . . . . . . . . 15
   4.  ASN.1 Translation  . . . . . . . . . . . . . . . . . . . . . . 16
     4.1.  Downgrading from X.68x to X.208  . . . . . . . . . . . . . 16
     4.2.  Upgrading from X.208 to X.68x  . . . . . . . . . . . . . . 16
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 17
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
     6.1.  Normative References . . . . . . . . . . . . . . . . . . . 18
     6.2.  Informative References . . . . . . . . . . . . . . . . . . 18

Wallace & Gardiner            Informational                     [Page 2]
RFC 6025                    ASN.1 Translation               October 2010

1.  Introduction

   This document is intended to serve as a tutorial for converting ASN.1
   modules written using [CCITT.X208.1988] to [CCITT.X680.2002], or vice
   versa.  Preparation of this document was motivated by [RFC5911] and
   [RFC5912], which provide updated ASN.1 modules for a number of RFCs.

   The intent of this specification is to assist with translation of
   ASN.1 from one version to another without resulting in any changes to