KEYPROV Working Group Sean Turner, IECA Internet Draft Russ Housley, Vigil Security Intended Status: Standard Track July 14, 2008 Expires: January 14, 2009 Symmetric Key Package Content Type draft-ietf-keyprov-symmetrickeyformat-03.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 14, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract This document defines the symmetric key format content type. It is transport independent. The Cryptographic Message Syntax can be used to digitally sign, digest, authenticate, or encrypt this content type. Turner & Housley Expires January 14, 2009 [Page 1] Internet-Draft Symmetric Key Package Content Type July 2008 Table of Contents 1. Introduction...................................................2 1.1. Requirements Terminology..................................2 1.2. ASN.1 Syntax Notation.....................................2 2. Use Cases......................................................3 2.1. Online Use Cases..........................................3 2.1.1. Transport of Keys from Server to Cryptomodule........3 2.1.2. Transport of Keys from Cryptomodule to Cryptomodule..3 2.1.3. Transport of Keys from Cryptomodule to Server........3 2.1.4. Server to Server Bulk Import/Export of Keys..........4 2.2. Offline Use Cases.........................................4 2.2.1. Server to Server Bulk Import/Export of Keys..........4 3. Symmetric Key Package Content Type.............................5 4. Security Considerations........................................6 5. IANA Considerations............................................6 6. References.....................................................6 6.1. Normative References......................................6 6.2. Non-Normative References..................................7 APPENDIX A: ASN.1 Module..........................................8 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 ASN.1 [X.680, X.681, X.682, X.683]. Turner & Housley Expires January 14, 2009 [Page 2] Internet-Draft Symmetric Key Package Content Type July 2008 2. Use Cases These use cases help in understanding the applicability of this specification to real world situations. 2.1. Online Use Cases This section describes the use cases related to provisioning the keys using an online provisioning protocol such as [DSKPP]. 2.1.1. Transport of Keys from Server to Cryptomodule For example, a mobile device user wants to obtain a symmetric key for use with a cryptomodule on the device. The cryptomodule client from vendor A initiates the provisioning process against a provisioning system from vendor B using a standards-based provisioning protocol such as [DSKPP]. The provisioning entity delivers one or more keys in a standard format that can be processed by the mobile device. For example, in a variation of the above, instead of the user's mobile phone, a key is provisioned in the user's soft token application on a laptop using a network-based online protocol. As before, the provisioning system delivers a key in a standard format that can be processed by the soft token on the PC. For example, the end-user or the key issuer wants to update or configure an existing key in the cryptomodule and requests a replacement key container. The container may or may not include a new key and may include new or updated key attributes such as a new counter value in HOTP key case, a modified response format or length, a new friendly name, etc. 2.1.2. Transport of Keys from Cryptomodule to Cryptomodule For example, a user wants to transport a key from one cryptomodule to another. There may be two cryptographic modules, one on a computer one on a mobile phone, and the user wants to transport a key from the computer to the mobile phone. The user can export the key and related data in a standard format for input into the other cryptomodule. 2.1.3. Transport of Keys from Cryptomodule to Server For example, a user wants to activate and use a new key and related data against a validation system that is not aware of this key. This key may be embedded in the cryptomodule (e.g., SD card, USB drive) that the user has purchased at the local electronics retailer. Along Turner & Housley Expires January 14, 2009 [Page 3] Internet-Draft Symmetric Key Package Content Type July 2008 with the cryptomodule, the user may get the key on a CD or a floppy in a standard format. The user can now upload via a secure online channel or import this key and related data into the new validation system and start using the key. 2.1.4. Server to Server Bulk Import/Export of Keys From time to time, a key management system may be required to import or export keys in bulk from one entity to another. For example, instead of importing keys from a manufacturer using a file, a validation server may download the keys using an online protocol. The keys can be downloaded in a standard format that can be processed by a validation system. For example, in a variation of the above, an OTA key provisioning gateway that provisions keys to mobile phones may obtain key material from a key issuer using an online protocol. The keys are delivered in a standard format that can be processed by the key provisioning gateway and subsequently sent to the end-user's mobile phone. 2.2. Offline Use Cases This section describes the use cases relating to offline transport of keys from one system to another, using some form of export and import model. 2.2.1. Server to Server Bulk Import/Export of Keys For example, cryptomodules such as OTP authentication tokens, may have their symmetric keys initialized during the manufacturing process in bulk, requiring copies of the keys and algorithm data to be loaded into the authentication system through a file on portable media. The manufacturer provides the keys and related data in the form of a file containing records in standard format, typically on a CD. Note that the token manufacturer and the vendor for the validation system may be the same or different. Some crypto modules will allow local PIN management (the device will have a PIN pad) hence random initial PINs set at manufacturing should be transmitted together with the respective keys they protect. For example, an enterprise wants to port keys and related data from an existing validation system A into a different validation system B. The existing validation system provides the enterprise with a functionality that enables export of keys and related data (e.g., for OTP authentication tokens) in a standard format. Since the OTP tokens are in the standard format, the enterprise can import the Turner & Housley Expires January 14, 2009 [Page 4] Internet-Draft Symmetric Key Package Content Type July 2008 token records into the new validation system B and start using the existing tokens. Note that the vendors for the two validation systems may be the same or different. 3. 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. This content type must be DER encoded [X.690]. 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 ::= | { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) ct(1) 25 } 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 OPTIONAL -- MUST contain sKeyAttrs, sKey, or sKeyAttrs and sKey } 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. Turner & Housley Expires January 14, 2009 [Page 5] Internet-Draft Symmetric Key Package Content Type July 2008 - sKeys contains a sequence of OneSymmetricKey values. This structure is discussed below. 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 optionally contains the key value encoded as an OCTET STRING. The OneSymmetricKey field MUST include either sKeyAttrs, sKey, or sKeyAttrs and sKey. 4. 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. 5. IANA Considerations None: All identifiers are already registered. Please remove this section prior to publication as an RFC. 6. References 6.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [X.680] ITU-T Recommendation X.680 (2002) | ISO/IEC 8824-1:2002. Information Technology - Abstract Syntax Notation One. [X.681] ITU-T Recommendation X.681 (2002) | ISO/IEC 8824-2:2002. Information Technology - Abstract Syntax Notation One: Information Object Specification. [X.682] ITU-T Recommendation X.682 (2002) | ISO/IEC 8824-3:2002. Information Technology - Abstract Syntax Notation One: Constraint Specification. [X.683] ITU-T Recommendation X.683 (2002) | ISO/IEC 8824-4:2002. Information Technology - Abstract Syntax Notation One: Parameterization of ASN.1 Specifications. Turner & Housley Expires January 14, 2009 [Page 6] Internet-Draft Symmetric Key Package Content Type July 2008 [X.690] ITU-T Recommendation X.690 (2002) | ISO/IEC 8825-1:2002. Information Technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER). 6.2. Non-Normative References [DSKPP] Doherty, A., Pei, M., Machani, S., and M. Nystrom, "Dynamic Symmetric Key Provisioning Protocol (DSKPP)", work-in-progress. [RFC3852] Housley, R., "Cryptographic Message Syntax (CMS)", RFC3852, July 2004. Turner & Housley Expires January 14, 2009 [Page 7] Internet-Draft Symmetric Key Package Content Type July 2008 APPENDIX A: ASN.1 Module This appendix provides the normative ASN.1 definitions for the structures described in this specification using ASN.1 as defined in [X.680] through [X.683]. SymmetricKeyPackageModulev1 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) 33 } 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 ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) ct(1) 25 } 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 OPTIONAL -- MUST contain sKeyAttrs, sKey, or sKeyAttrs and sKey } KeyPkgVersion ::= INTEGER { v1(1), ... } Turner & Housley Expires January 14, 2009 [Page 8] Internet-Draft Symmetric Key Package Content Type July 2008 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 AttributeValue ::= ATTRIBUTE.&Type Turner & Housley Expires January 14, 2009 [Page 9] Internet-Draft Symmetric Key Package Content Type July 2008 AttributeUsage ::= ENUMERATED { userApplications (0), directoryOperation (1), distributedOperation (2), dSAOperation (3) } END Author's Address Sean Turner IECA, Inc. 3057 Nutley Street, Suite 106 Fairfax, VA 22031 USA Email: turners@ieca.com Russ Housley Vigil Security, LLC 918 Spring Knoll Drive Herndon, VA 20170 USA EMail: housley@vigilsec.com Turner & Housley Expires January 14, 2009 [Page 10] Internet-Draft Symmetric Key Package Content Type July 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). 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