Network Working Group Sean Turner, IECA Internet Draft Russ Housley, Vigil Security Intended Status: Standard Track July 1, 2007 Expires: January 1, 2008 Symmetric Key Package Content Type draft-turner-symmetrickeyformat-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on January 1, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document defines the symmetric key format content type. It is transport independent. The Cryptographic Message Syntax [RFC3852] can be used to digitally sign, digest, authenticate, or encrypt this content type. Turner & Housley Expires January 1, 2008 [Page 1] Internet-Draft Symmetric Key Package Content Type July 2007 Table of Contents 1. Introduction...................................................2 1.1. Requirements Terminology..................................2 1.2. ASN.1 Syntax Notation.....................................2 2. Symmetric Key Package Content Type.............................3 3. Security Considerations........................................4 4. IANA Considerations............................................4 5. References.....................................................4 5.1. Normative References......................................4 5.2. Non-Normative References..................................4 APPENDIX A: ASN.1 Modules.........................................5 A.1. X.680 ASN.1 Module........................................5 A.2. X.208 ASN.1 Module........................................7 1. Introduction This document defines the symmetric key format content type. It is transport independent. The Cryptographic Message Syntax [RFC3852] can be used to digitally sign, digest, authenticate, or encrypt this content type. 1.1. Requirements 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 [RFC2119]. 1.2. ASN.1 Syntax Notation The key package is defined using the '93 ASN.1 [X.680, X.690]. A module for the '88 [X.208, X.209] and the '93 ASN.1 syntax are included. They result in the same encoding on the wire. Turner & Housley Expires January 1, 2008 [Page 2] Internet-Draft Symmetric Key Package Content Type July 2007 2. Symmetric Key Package Content Type The symmetric key package content type is used to transfer one or more plaintext symmetric keys from one party to another. A symmetric key package MAY be encapsulated in one or more CMS protecting content types. The symmetric key package content type has the following syntax: PKCS7-CONTENT-TYPE ::= TYPE-IDENTIFIER symmetric-key-package PKCS7-CONTENT-TYPE ::= { SymmetricKeyPackage IDENTIFIED BY id-ct-KP-sKeyPackage } id-ct-KP-sKeyPackage OBJECT IDENTIFIER ::= | { TBD } SymmetricKeyPackage ::= SEQUENCE { version KeyPkgVersion DEFAULT v1, sKeyPkgAtts [0] SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL, sKeys SymmetricKeys } SymmetricKeys ::= SEQUENCE SIZE (1..MAX) OF OneSymmetricKey OneSymmetricKey ::= SEQUENCE { sKeyAttrs SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL, sKey OCTET STRING } KeyPkgVersion ::= INTEGER { v1(1), ... } The SymmetricKeyPackage fields are used as follows: - version identifies version of the symmetric key package content structure. For this version of the specification, the default value, v1, MUST be used. - sKeyPkgAttrs optionally provides attributes that apply to all of the symmetric keys in the package. If an attribute appears here it MUST not also be included in sKeyAttrs. - sKeys contains a sequence of OneSymmetricKey values. This structure is discussed below. Turner & Housley Expires January 1, 2008 [Page 3] Internet-Draft Symmetric Key Package Content Type July 2007 The OneSymmetricKey fields are used as follows: - sKeyAttrs optionally provides attributes that apply to one symmetric key. If an attribute appears here it MUST not also be included in sKeyPkgAttrs. - sKey contains the key value encoded as an OCTET STRING. 3. Security Considerations The symmetric key package contents are not protected. This content type can be combined with a security protocol to protect the contents of the package. 4. IANA Considerations None: All identifiers are already registered. Please remove this section prior to publication as an RFC. 5. References 5.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [X.208] ITU-T Recommendation X.208: Information Technology - Abstract Syntax Notation One, 1988. [X.209] ITU-T Recommendation X.209 Information Technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER), 1988. [X.680] ITU-T Recommendation X.680: Information Technology - Abstract Syntax Notation One, 1997. [X.690] ITU-T Recommendation X.690 Information Technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER), 1997. 5.2. Non-Normative References [RFC3852] Housley, R., "Cryptographic Message Syntax (CMS)", RFC3852, July 2004. Turner & Housley Expires January 1, 2008 [Page 4] Internet-Draft Symmetric Key Package Content Type July 2007 APPENDIX A: ASN.1 Modules Appendix A.1 provides the normative ASN.1 definitions for the structures described in this specification using ASN.1 as defined in X.680. Appendix A.2 provides a module using ASN.1 as defined in [X.208]. The module in A.2 removes usage of newer ASN.1 features that provide support for limiting the types of elements that may appear in certain SEQUENCE and SET constructions. Otherwise, the modules are compatible in terms of encoded representation, i.e., the modules are bits-on-the-wire compatible aside from the limitations on SEQUENCE and SET constituents. A.2 is included as a courtesy to developers using ASN.1 compilers that do not support current ASN.1. A.1. X.680 ASN.1 Module SymmetricKeyPackageModulev1-93 { tbd } DEFINITIONS IMPLICIT TAGS ::= BEGIN -- EXPORTS ALL -- IMPORTS NOTHING PKCS7-CONTENT-TYPE ::= TYPE-IDENTIFIER KeyPackageContentTypes PKCS7-CONTENT-TYPE ::= { symmetric-key-package | ... -- Expect additional content types -- } symmetric-key-package PKCS7-CONTENT-TYPE ::= { SymmetricKeyPackage IDENTIFIED BY id-ct-KP-sKeyPackage } id-ct-KP-sKeyPackage OBJECT IDENTIFIER ::= { TBD } SymmetricKeyPackage ::= SEQUENCE { version KeyPkgVersion DEFAULT v1, sKeyPkgAttrs [0] SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL, sKeys SymmetricKeys } SymmetricKeys ::= SEQUENCE SIZE (1..MAX) OF OneSymmetricKey Turner & Housley Expires January 1, 2008 [Page 5] Internet-Draft Symmetric Key Package Content Type July 2007 OneSymmetricKey ::= SEQUENCE { sKeyAttrs SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL, sKey OCTET STRING } KeyPkgVersion ::= INTEGER { v1(1), ... } Attribute ::= SEQUENCE { type ATTRIBUTE.&id ({SupportedAttributes}), values SET SIZE (1..MAX) OF ATTRIBUTE.&Type ({SupportedAttributes}{@type}) } SupportedAttributes ATTRIBUTE ::= { ... } ATTRIBUTE ::= CLASS { &derivation ATTRIBUTE OPTIONAL, &Type OPTIONAL, -- either &Type or &derivation required &equality-match MATCHING-RULE OPTIONAL, &ordering-match MATCHING-RULE OPTIONAL, &substrings-match MATCHING-RULE OPTIONAL, &single-valued BOOLEAN DEFAULT FALSE, &collective BOOLEAN DEFAULT FALSE, -- operational extensions &no-user-modification BOOLEAN DEFAULT FALSE, &usage AttributeUsage DEFAULT userApplications, &id OBJECT IDENTIFIER UNIQUE } WITH SYNTAX { [ SUBTYPE OF &derivation ] [ WITH SYNTAX &Type ] [ EQUALITY MATCHING RULE &equality-match ] [ ORDERING MATCHING RULE &ordering-match ] [ SUBSTRINGS MATCHING RULE &substrings-match ] [ SINGLE VALUE &single-valued ] [ COLLECTIVE &collective ] [ NO USER MODIFICATION &no-user-modification ] [ USAGE &usage ] ID &id } MATCHING-RULE ::= CLASS { &AssertionType OPTIONAL, &id OBJECT IDENTIFIER UNIQUE } WITH SYNTAX { [ SYNTAX &AssertionType ] ID &id } AttributeType ::= ATTRIBUTE.&id Turner & Housley Expires January 1, 2008 [Page 6] Internet-Draft Symmetric Key Package Content Type July 2007 AttributeValue ::= ATTRIBUTE.&Type AttributeUsage ::= ENUMERATED { userApplications (0), directoryOperation (1), distributedOperation (2), dSAOperation (3) } END A.2. X.208 ASN.1 Module SymmetricKeyPackageModulev1-88 { tbd } DEFINITIONS IMPLICIT TAGS ::= BEGIN -- EXPORTS ALL -- IMPORTS NOTHING -- Symmetric Key Package Content Type and Object Identifier id-ct-KP-sKeyPackage OBJECT IDENTIFIER ::= { TBD } SymmetricKeyPackage ::= SEQUENCE { version KeyPkgVersion DEFAULT v1, sKeyPkgAttrs [0] SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL, sKeys SymmetricKeys } SymmetricKeys ::= SEQUENCE SIZE (1..MAX) OF OneSymmetricKey OneSymmetricKey ::= SEQUENCE { sKeyAttrs SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL, sKey OCTET STRING } KeyPkgVersion ::= INTEGER { v1(1), ... } Attribute ::= SEQUENCE { attrType OBJECT IDENTIFIER, attrValues SET OF AttributeValue } AttributeValue ::= ANY END Turner & Housley Expires January 1, 2008 [Page 7] Internet-Draft Symmetric Key Package Content Type July 2007 Editor's Address Sean Turner IECA, Inc. Email: turners (at) ieca (dot) com Russ Housley Vigil Security Email: housley (at) vigilsec (dot) com Turner & Housley Expires January 1, 2008 [Page 8] Internet-Draft Symmetric Key Package Content Type July 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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