6031
PROPOSED STANDARD
Cryptographic Message Syntax (CMS) Symmetric Key Package Content Type
Authors: S. Turner, R. Housley
Date: December 2010
Area: sec
Working Group: keyprov
Stream: IETF
Abstract
This document defines the symmetric key format content type. It is transport independent. The Cryptographic Message Syntax (CMS) can be used to digitally sign, digest, authenticate, or encrypt this content type. [STANDARDS-TRACK]
RFC 6031
PROPOSED STANDARD
Errata Exist
Internet Engineering Task Force (IETF) S. Turner
Request for Comments: 6031 IECA
Category: Standards Track R. Housley
ISSN: 2070-1721 Vigil Security
December 2010
<span class="h1">Cryptographic Message Syntax (CMS) Symmetric Key Package Content Type</span>
Abstract
This document defines the symmetric key format content type. It is
transport independent. The Cryptographic Message Syntax (CMS) can be
used to digitally sign, digest, authenticate, or encrypt this content
type.
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 <a href="./rfc5741#section-2">Section 2 of RFC 5741</a>.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
<a href="https://www.rfc-editor.org/info/rfc6031">http://www.rfc-editor.org/info/rfc6031</a>.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and the IETF Trust's Legal
Provisions Relating to IETF Documents
(<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) 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.
<span class="grey">Turner & Housley Standards Track [Page 1]</span><span id="page-2" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
Table of Contents
<a href="#section-1">1</a>. Introduction...................................................<a href="#page-3">3</a>
<a href="#section-1.1">1.1</a>. Requirements Terminology..................................<a href="#page-3">3</a>
<a href="#section-1.2">1.2</a>. ASN.1 Syntax Notation.....................................<a href="#page-3">3</a>
<a href="#section-2">2</a>. Symmetric Key Package Content Type.............................<a href="#page-3">3</a>
<a href="#section-3">3</a>. PSKC Attributes................................................<a href="#page-4">4</a>
<a href="#section-3.1">3.1</a>. PSKC Key Package Attributes...............................<a href="#page-5">5</a>
<a href="#section-3.1.1">3.1.1</a>. Device Information Attributes........................<a href="#page-5">5</a>
<a href="#section-3.1.2">3.1.2</a>. Cryptographic Module Information Attributes..........<a href="#page-8">8</a>
<a href="#section-3.2">3.2</a>. PSKC Key Attributes.......................................<a href="#page-8">8</a>
<a href="#section-3.2.1">3.2.1</a>. Key Identifier.......................................<a href="#page-8">8</a>
<a href="#section-3.2.2">3.2.2</a>. Algorithm............................................<a href="#page-9">9</a>
<a href="#section-3.2.3">3.2.3</a>. Issuer...............................................<a href="#page-9">9</a>
<a href="#section-3.2.4">3.2.4</a>. Key Profile Identifier...............................<a href="#page-9">9</a>
<a href="#section-3.2.5">3.2.5</a>. Key Reference Identifier.............................<a href="#page-9">9</a>
<a href="#section-3.2.6">3.2.6</a>. Friendly Name.......................................<a href="#page-10">10</a>
<a href="#section-3.2.7">3.2.7</a>. Algorithm Parameters................................<a href="#page-10">10</a>
<a href="#section-3.2.8">3.2.8</a>. Counter.............................................<a href="#page-12">12</a>
<a href="#section-3.2.9">3.2.9</a>. Time................................................<a href="#page-13">13</a>
<a href="#section-3.2.10">3.2.10</a>. Time Interval......................................<a href="#page-13">13</a>
<a href="#section-3.2.11">3.2.11</a>. Time Drift.........................................<a href="#page-13">13</a>
<a href="#section-3.2.12">3.2.12</a>. Value MAC..........................................<a href="#page-13">13</a>
<a href="#section-3.2.13">3.2.13</a>. Key User Id........................................<a href="#page-14">14</a>
<a href="#section-3.3">3.3</a>. Key Policy Attributes....................................<a href="#page-14">14</a>
<a href="#section-3.3.1">3.3.1</a>. Key Start Date......................................<a href="#page-14">14</a>
<a href="#section-3.3.2">3.3.2</a>. Key Expiry Date.....................................<a href="#page-15">15</a>
<a href="#section-3.3.3">3.3.3</a>. Number of Transactions..............................<a href="#page-15">15</a>
<a href="#section-3.3.4">3.3.4</a>. Key Usage...........................................<a href="#page-15">15</a>
<a href="#section-3.3.5">3.3.5</a>. PIN Policy..........................................<a href="#page-16">16</a>
<a href="#section-4">4</a>. Key Encoding..................................................<a href="#page-18">18</a>
<a href="#section-4.1">4.1</a>. AES Key Encoding.........................................<a href="#page-18">18</a>
<a href="#section-4.2">4.2</a>. Triple-DES Key Encoding..................................<a href="#page-18">18</a>
<a href="#section-5">5</a>. Security Considerations.......................................<a href="#page-19">19</a>
<a href="#section-6">6</a>. IANA Considerations...........................................<a href="#page-19">19</a>
<a href="#section-7">7</a>. References....................................................<a href="#page-19">19</a>
<a href="#section-7.1">7.1</a>. Normative References.....................................<a href="#page-19">19</a>
<a href="#section-7.2">7.2</a>. Informative References...................................<a href="#page-21">21</a>
<a href="#appendix-A">Appendix A</a>. ASN.1 Module.........................................<a href="#page-22">22</a>
<a href="#appendix-A.1">A.1</a>. Symmetric Key Package ASN.1 Module.......................<a href="#page-22">22</a>
<a href="#appendix-A.2">A.2</a>. PSKC ASN.1 Module........................................<a href="#page-23">23</a>
<span class="grey">Turner & Housley Standards Track [Page 2]</span><span id="page-3" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span>
This document defines the symmetric key format content type. It is
transport independent. The Cryptographic Message Syntax (CMS)
[<a href="./rfc5652" title=""Cryptographic Message Syntax (CMS)"">RFC5652</a>] can be used to digitally sign, digest, authenticate, or
encrypt this content type.
The use cases that motivated the attributes in this work are
elaborated in [<a href="./rfc6030" title=""Portable Symmetric Key Container (PSKC)"">RFC6030</a>]. They are omitted to avoid duplication.
This document also includes ASN.1 definitions of the Extensible
Markup Language (XML) element and attributes defined in [<a href="./rfc6030" title=""Portable Symmetric Key Container (PSKC)"">RFC6030</a>].
<span class="h3"><a class="selflink" id="section-1.1" href="#section-1.1">1.1</a>. Requirements Terminology</span>
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 [<a href="./rfc2119" title=""Key words for use in RFCs to Indicate Requirement Levels"">RFC2119</a>].
<span class="h3"><a class="selflink" id="section-1.2" href="#section-1.2">1.2</a>. ASN.1 Syntax Notation</span>
The key package is defined using the ASN.1 in [<a href="#ref-X.680">X.680</a>], [<a href="#ref-X.681">X.681</a>],
[<a href="#ref-X.682">X.682</a>], and [<a href="#ref-X.683">X.683</a>].
<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Symmetric Key Package Content Type</span>
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 Distinguished Encoding Rules (DER)
encoded [<a href="#ref-X.690">X.690</a>].
The symmetric key package content type has the following syntax:
ct-symmetric-key-package CONTENT-TYPE ::=
{ 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
{{ SKeyPkgAttributes }} OPTIONAL,
sKeys SymmetricKeys,
... }
<span class="grey">Turner & Housley Standards Track [Page 3]</span><span id="page-4" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
SymmetricKeys ::= SEQUENCE SIZE (1..MAX) OF OneSymmetricKey
OneSymmetricKey ::= SEQUENCE {
sKeyAttrs SEQUENCE SIZE (1..MAX) OF Attribute
{{ SKeyAttributes }} OPTIONAL,
sKey OCTET STRING OPTIONAL }
( WITH COMPONENTS { ..., sKeyAttrs PRESENT } |
WITH COMPONENTS { ..., sKey PRESENT } )
KeyPkgVersion ::= INTEGER { v1(1) } ( v1, ... )
The SymmetricKeyPackage fields are used as follows:
- version identifies the 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. The SKeyPkgAttributes
information object set restricts the attributes allowed in
sKeyPkgAttrs. If an attribute appears here, then it MUST NOT also
be included in sKeyAttrs.
- 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. The SKeyAttributes information object set restricts
the attributes permitted in sKeyAttrs. If an attribute appears
here, then it MUST NOT also be included in sKeyPkgAttrs.
- sKey optionally contains the key value encoded as an OCTET STRING.
The OneSymmetricKey field MUST include sKeyAttrs, sKey, or sKeyAttrs
and sKey.
<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. PSKC Attributes</span>
The following attributes are defined to assist those using the
symmetric key package defined in this document as part of a Dynamic
Symmetric Key Provision Protocol (DSKPP) [<a href="./rfc6063" title=""Dynamic Symmetric Key Provisioning Protocol (DSKPP)"">RFC6063</a>] with Portable
Symmetric Key Container (PSKC) attributes. [<a href="./rfc6030" title=""Portable Symmetric Key Container (PSKC)"">RFC6030</a>] should be
consulted for the definitive attribute descriptions. The attributes
fall into three categories. The first category includes attributes
that apply to a key package, and these attributes will generally
appear in sKeyPkgAttrs. The second category includes attributes that
<span class="grey">Turner & Housley Standards Track [Page 4]</span><span id="page-5" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
apply to a particular key, and these attributes will generally appear
in sKeyAttrs. The third category includes attributes that apply to a
key policy. Of the attributes defined, only the Key Identifier
(<a href="#section-3.2.1">Section 3.2.1</a>) and Algorithm (<a href="#section-3.2.2">Section 3.2.2</a>) key attributes MUST be
included. All other attributes are OPTIONAL.
Like PSKC, the Symmetric Key Content Type supports extensibility.
Primarily, this is accomplished through the definition and inclusion
of new attributes, but in some instances in which the attribute
contains more than one type, the ASN.1 "..." extensibility mechanism
is employed.
A straightforward approach to conversion from XML types to ASN.1 is
employed. The <xs:string> type converts to UTF8String; the XML
<xs:dateTime> type converts to GeneralizedTime; and the XML integer
types convert to INTEGER or BinaryTime [<a href="./rfc6019" title=""BinaryTime: An Alternate Format for Representing Date and Time in ASN.1"">RFC6019</a>].
<span class="h3"><a class="selflink" id="section-3.1" href="#section-3.1">3.1</a>. PSKC Key Package Attributes</span>
PSKC key package attributes apply to an entire key package. These
attributes can be categorized by two different attribute collections:
device information and cryptographic module attributes. All of these
key package attributes are OPTIONAL.
<span class="h4"><a class="selflink" id="section-3.1.1" href="#section-3.1.1">3.1.1</a>. Device Information Attributes</span>
Device Information attributes, when taken together, MUST uniquely
identify a device to which the Symmetric Key Package is provisioned.
<span class="h5"><a class="selflink" id="section-3.1.1.1" href="#section-3.1.1.1">3.1.1.1</a>. Manufacturer</span>
The Manufacturer attribute indicates the manufacturer of the device.
Values for Manufacturer MUST be taken from either [<a href="#ref-OATHMAN" title=""List of OATH Manufacturer Prefixes (omp)"">OATHMAN</a>] prefixes
(i.e., the left column) or from the IANA Private Enterprise Number
Registry [<a href="#ref-IANAPENREG" title=""Private Enterprise Numbers"">IANAPENREG</a>], using the Organization value. When the value
is taken from [<a href="#ref-OATHMAN" title=""List of OATH Manufacturer Prefixes (omp)"">OATHMAN</a>] "oath." MUST be prepended to the value (e.g.,
"oath.<values from [<a href="#ref-OATHMAN" title=""List of OATH Manufacturer Prefixes (omp)"">OATHMAN</a>]>"). When the value is taken from
[<a href="#ref-IANAPENREG" title=""Private Enterprise Numbers"">IANAPENREG</a>], "iana." MUST be prepended to the value (e.g.,
"iana.<Organization value from [<a href="#ref-IANAPENREG" title=""Private Enterprise Numbers"">IANAPENREG</a>]>"). The attribute
definition is as follows:
at-pskc-manufacturer ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-manufacturer }
id-pskc-manufacturer OBJECT IDENTIFIER ::= { id-pskc 1 }
<span class="grey">Turner & Housley Standards Track [Page 5]</span><span id="page-6" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
<span class="h5"><a class="selflink" id="section-3.1.1.2" href="#section-3.1.1.2">3.1.1.2</a>. Serial Number</span>
The Serial Number attribute indicates the serial number of the
device. The attribute definition is as follows:
at-pskc-serialNo ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-serialNo }
id-pskc-serialNo OBJECT IDENTIFIER ::= { id-pskc 2 }
<span class="h5"><a class="selflink" id="section-3.1.1.3" href="#section-3.1.1.3">3.1.1.3</a>. Model</span>
The Model attribute indicates the model of the device. The attribute
definition is as follows:
at-pskc-model ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-model }
id-pskc-model OBJECT IDENTIFIER ::= { id-pskc 3 }
<span class="h5"><a class="selflink" id="section-3.1.1.4" href="#section-3.1.1.4">3.1.1.4</a>. Issue Number</span>
The Issue Number attribute contains an issue number to distinguish
between two devices with the same serial number. The attribute
definition is as follows:
at-pskc-issueNo ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-issueNo }
id-pskc-issueNo OBJECT IDENTIFIER ::= { id-pskc 4 }
<span class="h5"><a class="selflink" id="section-3.1.1.5" href="#section-3.1.1.5">3.1.1.5</a>. Device Binding</span>
The Device Binding attribute provides an opaque identifier that
allows keys to be bound to the device or to a class of devices.
When loading keys into a device, the attribute's value MUST be
checked against information provided to the user via out-of-band
mechanisms. The implementation then ensures that the correct device
or class of device is being used with respect to the provisioned key.
at-pskc-deviceBinding ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-deviceBinding }
id-pskc-deviceBinding OBJECT IDENTIFIER ::= { id-pskc 5 }
<span class="grey">Turner & Housley Standards Track [Page 6]</span><span id="page-7" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
<span class="h5"><a class="selflink" id="section-3.1.1.6" href="#section-3.1.1.6">3.1.1.6</a>. Device Start Date</span>
When included in sKeyPkgAttrs, the Device Start Date attribute
indicates the start date for a device. The date MUST be represented
in a form that matches the dateTime production in "canonical
representation" [<a href="#ref-XMLSCHEMA" title=""XML Schema Part 2: Datatypes Second Edition"">XMLSCHEMA</a>]. Implementations SHOULD NOT rely on time
resolution finer than milliseconds and MUST NOT generate time
instants that specify leap seconds. Keys that are on the device
SHOULD only be used when the current date is on or after the device
start date. The attribute definition is as follows:
at-pskc-deviceStartDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-deviceStartDate }
id-pskc-deviceStartDate OBJECT IDENTIFIER ::= { id-pskc 6 }
Note that usage enforcement of the keys with respect to the dates MAY
only happen on the validation server as some devices, such as smart
cards, do not have an internal clock. Systems thus SHOULD NOT rely
upon the device to enforce key usage date restrictions.
<span class="h5"><a class="selflink" id="section-3.1.1.7" href="#section-3.1.1.7">3.1.1.7</a>. Device Expiry Date</span>
When included in sKeyPkgAttrs, the Device Expiry Date attribute
indicates the expiry date for a device. The date MUST be represented
in a form that matches the dateTime production in "canonical
representation" [<a href="#ref-XMLSCHEMA" title=""XML Schema Part 2: Datatypes Second Edition"">XMLSCHEMA</a>]. Implementations SHOULD NOT rely on time
resolution finer than milliseconds and MUST NOT generate time
instants that specify leap seconds. Keys that are on the device
SHOULD only be used when the current date is before the device expiry
date. The attribute definition is as follows:
at-pskc-deviceExpiryDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-deviceExpiryDate }
id-pskc-deviceExpiryDate OBJECT IDENTIFIER ::= { id-pskc 7 } Note
that usage enforcement of the keys with respect to the dates MAY only
happen on the validation server as some devices, such as smart cards,
do not have an internal clock. Systems thus SHOULD NOT rely upon the
device to enforce key usage date restrictions.
<span class="h5"><a class="selflink" id="section-3.1.1.8" href="#section-3.1.1.8">3.1.1.8</a>. Device User Id</span>
The Device User Id attribute indicates the user with whom the device
is associated using a distinguished name, as defined in [<a href="./rfc4514" title=""Lightweight Directory Access Protocol (LDAP): String Representation of Distinguished Names"">RFC4514</a>].
For example: UID=jsmith,DC=example,DC=net. The attribute definition
is as follows:
<span class="grey">Turner & Housley Standards Track [Page 7]</span><span id="page-8" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
at-pskc-deviceUserId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-deviceUserId }
id-pskc-deviceUserId OBJECT IDENTIFIER ::= { id-pskc 26 }
As specified in [<a href="./rfc6030" title=""Portable Symmetric Key Container (PSKC)"">RFC6030</a>], there are no semantics associated with
this element, i.e., there are no checks enforcing that only a
specific user can use this device. As such, this element is for
informational purposes only.
<span class="h4"><a class="selflink" id="section-3.1.2" href="#section-3.1.2">3.1.2</a>. Cryptographic Module Information Attributes</span>
Cryptographic Module attributes uniquely identify a cryptographic
module. This is useful when the device contains more than one
cryptographic module. At this time, only one attribute is defined.
<span class="h5"><a class="selflink" id="section-3.1.2.1" href="#section-3.1.2.1">3.1.2.1</a>. Cryptographic Module Identifier</span>
When included in sKeyPkgAttrs, the Cryptographic Module Identifier
attribute uniquely identifies the cryptographic module to which the
key is being or was provisioned. The attribute definition is as
follows:
at-pskc-moduleId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-moduleId }
id-pskc-moduleId OBJECT IDENTIFIER ::= { id-pskc 8 }
<span class="h3"><a class="selflink" id="section-3.2" href="#section-3.2">3.2</a>. PSKC Key Attributes</span>
PSKC key attributes apply to a specific key. As noted earlier, the
Key Identifier (<a href="#section-3.2.1">Section 3.2.1</a>) and Algorithm (<a href="#section-3.2.2">Section 3.2.2</a>) key
attributes are REQUIRED. All other attributes are OPTIONAL.
<span class="h4"><a class="selflink" id="section-3.2.1" href="#section-3.2.1">3.2.1</a>. Key Identifier</span>
When included in sKeyAttrs, the Key Identifier attribute identifies
the key in the context of key provisioning exchanges between two
parties. This means that if PSKC is used in multiple interactions
between a sending and receiving party, using different containers
referencing the same keys, the KeyId MUST use the same KeyId values
(e.g., after initial provisioning, if a system wants to update key
metadata values in the other system, the KeyId value of the key where
the metadata is to be updates MUST be the same as the original KeyId
value provisioned). The attribute definition is as follows:
<span class="grey">Turner & Housley Standards Track [Page 8]</span><span id="page-9" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
at-pskc-keyId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyId }
id-pskc-keyId OBJECT IDENTIFIER ::= { id-pskc 9 }
<span class="h4"><a class="selflink" id="section-3.2.2" href="#section-3.2.2">3.2.2</a>. Algorithm</span>
The Algorithm attribute uniquely identifies the PSKC algorithm
profile. [<a href="./rfc6030" title=""Portable Symmetric Key Container (PSKC)"">RFC6030</a>] defines two algorithm profiles "HOTP" and "PIN".
The attribute definition is as follows:
at-pskc-algorithm ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-algorithm }
id-pskc-algorithm OBJECT IDENTIFIER ::= { id-pskc 10 }
<span class="h4"><a class="selflink" id="section-3.2.3" href="#section-3.2.3">3.2.3</a>. Issuer</span>
The Issuer attribute names the entity that issued the key. The
attribute definition is as follows:
at-pskc-issuer ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-issuer }
id-pskc-issuer OBJECT IDENTIFIER ::= { id-pskc 11 }
<span class="h4"><a class="selflink" id="section-3.2.4" href="#section-3.2.4">3.2.4</a>. Key Profile Identifier</span>
The Key Profile Identifier attribute carries a unique identifier used
between the sending and receiving parties to establish a set of key
attribute values that are not transmitted within the container but
are agreed upon between the two parties out of band. This attribute
will then represent the unique reference to a set of key attribute
values.
at-pskc-keyProfileId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyProfileId }
id-pskc-keyProfileId OBJECT IDENTIFIER ::= { id-pskc 12 }
<span class="h4"><a class="selflink" id="section-3.2.5" href="#section-3.2.5">3.2.5</a>. Key Reference Identifier</span>
The Key Reference attribute refers to an external key to be used with
a key derivation scheme and no specific key value (secret) is
transported; only the reference to the external master key is used
(e.g., the PKCS #11 key label).
<span class="grey">Turner & Housley Standards Track [Page 9]</span><span id="page-10" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
at-pskc-keyReference ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyReference }
id-pskc-keyReference OBJECT IDENTIFIER ::= { id-pskc 13 }
<span class="h4"><a class="selflink" id="section-3.2.6" href="#section-3.2.6">3.2.6</a>. Friendly Name</span>
The Friendly Name attribute contains a human-readable name for the
secret key. The attribute definition is as follows:
at-pskc-friendlyName ATTRIBUTE ::= {
TYPE FriendlyName IDENTIFIED BY id-pskc-friendlyName }
id-pskc-friendlyName OBJECT IDENTIFIER ::= { id-pskc 14 }
The Friendly Name attribute has the following syntax:
FriendlyName ::= SEQUENCE {
friendlyName UTF8String,
friendlyNameLangTag UTF8String OPTIONAL }
The text is encoded in UTF-8 [<a href="./rfc3629" title=""UTF-8, a transformation format of ISO 10646"">RFC3629</a>], which accommodates most of
the world's writing systems. The friendlyNameLangTag field
identifies the language used to express the friendlyName. When the
friendlyNameLangTag field is absent, English, whose associated
language tag is "en", is used. The value of the friendlyNameLangTag
field MUST be a language tag, as described in [<a href="./rfc5646" title=""Tags for Identifying Languages"">RFC5646</a>].
<span class="h4"><a class="selflink" id="section-3.2.7" href="#section-3.2.7">3.2.7</a>. Algorithm Parameters</span>
The Algorithm Parameters attribute contains parameters that influence
the result of the algorithmic computation, for example, response
truncation and format in One-Time Password (OTP) and
Challenge/Response (CR) algorithms.
at-pskc-algorithmParameters ATTRIBUTE ::= {
TYPE PSKCAlgorithmParameters
IDENTIFIED BY id-pskc-algorithmParams }
id-pskc-algorithmParams OBJECT IDENTIFIER ::= { id-pskc 15 }
The Algorithm Parameters attribute has the following syntax:
PSKCAlgorithmParameters ::= CHOICE {
suite UTF8String,
challengeFormat [0] ChallengeFormat,
responseFormat [1] ResponseFormat,
... }
<span class="grey">Turner & Housley Standards Track [Page 10]</span><span id="page-11" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
ChallengeFormat ::= SEQUENCE {
encoding Encoding,
checkDigit BOOLEAN DEFAULT FALSE,
min INTEGER (0..MAX),
max INTEGER (0..MAX),
... }
Encoding ::= UTF8STRING ("DECIMAL" | "HEXADECIMAL" |
"ALPHANUMERIC" |"BASE64" |"BINARY")
ResponseFormat ::= SEQUENCE {
encoding Encoding,
length INTEGER (0..MAX),
checkDigit BOOLEAN DEFAULT FALSE,
... }
The fields in PSKCAlgorithmParameters have the following meanings:
o Suite defines additional characteristics of the algorithm used,
which are algorithm specific. For example, in an HMAC-based
(Hashed Message Authentication Code) OTP algorithm it could
designate the strength of the hash algorithm used (SHA1, SHA256,
etc.). Please refer to the algorithm profile specification
[<a href="./rfc6030" title=""Portable Symmetric Key Container (PSKC)"">RFC6030</a>] for the exact semantics of the value for each algorithm
profile.
o ChallengeFormat defines the characteristics of the challenge in a
CR usage scenario, whereby the following fields are defined:
o encoding specifies the encoding of the challenge accepted by the
device and MUST be one of the following values: DECIMAL,
HEXADECIMAL, ALPHANUMERIC, BASE64, or BINARY. The BASE64
encoding is done as in <a href="./rfc4648#section-4">Section 4 of [RFC4648]</a>.
o checkDigit indicates whether a device needs to check the
appended Luhn check digit, as defined in [<a href="#ref-ISOIEC7812" title=""ISO/IEC 7812-1:2006 Identification cards -- Identification of issuers -- Part 1: Numbering system"">ISOIEC7812</a>], contained
in a challenge. The checkDigit MUST NOT be present if the
encoding value is anything other than 'DECIMAL'. A value of
TRUE indicates that the device will check the appended Luhn
check digit in a provided challenge. A value of FALSE indicates
that the device will not check the appended Luhn check digit in
the challenge.
<span class="grey">Turner & Housley Standards Track [Page 11]</span><span id="page-12" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
o min defines the minimum size of the challenge accepted by the
device for CR mode. If encoding is 'DECIMAL', 'HEXADECIMAL', or
'ALPHANUMERIC', this value indicates the minimum number of
digits/characters. If encoding is 'BASE64' or 'BINARY', this
value indicates the minimum number of bytes of the unencoded
value.
o max defines the maximum size of the challenge accepted by the
device for CR mode. If encoding is 'DECIMAL', 'HEXADECIMAL', or
'ALPHANUMERIC', this value indicates the maximum number of
digits/characters. If the encoding is 'BASE64' or 'BINARY',
this value indicates the maximum number of bytes of the
unencoded value.
o ResponseFormat defines the characteristics of the result of a
computation and defines the format of the OTP or the response to a
challenge. For cases where the key is a personal identification
number (PIN) value, this element contains the format of the PIN
itself (e.g., DECIMAL, length 4 for a 4 digit PIN). The following
fields are defined:
o encoding specifies the encoding of the response generated by the
device and MUST be one of the following values: DECIMAL,
HEXADECIMAL, ALPHANUMERIC, BASE64, or BINARY. BASE64 is defined
as in <a href="./rfc4648#section-4">Section 4 of [RFC4648]</a>.
o length defines the length of the response generated by the
device. If encoding is 'DECIMAL', 'HEXADECIMAL', or
'ALPHANUMERIC', this value indicates the number of
digits/characters. If encoding is 'BASE64' or 'BINARY', this
value indicates the number of bytes of the unencoded value.
o checkDigit indicates whether the device needs to append a Luhn
check digit, as defined in [<a href="#ref-ISOIEC7812" title=""ISO/IEC 7812-1:2006 Identification cards -- Identification of issuers -- Part 1: Numbering system"">ISOIEC7812</a>], to the response. This
is only valid if the encoding attribute is 'DECIMAL'. If the
value is TRUE, then the device will append a Luhn check digit to
the response. If the value is FALSE, then the device will not
append a Luhn check digit to the response.
<span class="h4"><a class="selflink" id="section-3.2.8" href="#section-3.2.8">3.2.8</a>. Counter</span>
The Counter attribute contains the event counter for event-based OTP
algorithms. The attribute definition is as follows:
at-pskc-counter ATTRIBUTE ::= {
TYPE INTEGER(0..MAX) IDENTIFIED BY id-pskc-counter }
id-pskc-counter OBJECT IDENTIFIER ::= { id-pskc 16 }
<span class="grey">Turner & Housley Standards Track [Page 12]</span><span id="page-13" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
<span class="h4"><a class="selflink" id="section-3.2.9" href="#section-3.2.9">3.2.9</a>. Time</span>
The Time attribute conveys the time for time-based OTP algorithms.
If the Time Interval attribute is included, then this element carries
the number of time intervals passed for a specific start point. If
the time interval is used, then this element carries the number of
time intervals passed from a specific start point, normally it is
algorithm dependent. It uses the BinaryTime syntax from [<a href="./rfc6019" title=""BinaryTime: An Alternate Format for Representing Date and Time in ASN.1"">RFC6019</a>].
The attribute definition is as follows:
at-pskc-time ATTRIBUTE ::= {
TYPE BinaryTime IDENTIFIED BY id-pskc-time }
id-pskc-time OBJECT IDENTIFIER ::= { id-pskc 17 }
<span class="h4"><a class="selflink" id="section-3.2.10" href="#section-3.2.10">3.2.10</a>. Time Interval</span>
The Time Interval attribute conveys the time interval value for time-
based OTP algorithms in seconds (e.g., a value of 30 for this would
indicate a time interval of 30 seconds). It is an integer. The
attribute definition is as follows:
at-pskc-timeInterval ATTRIBUTE ::= {
TYPE INTEGER (0..MAX) IDENTIFIED BY id-pskc-timeInterval }
id-pskc-timeInterval OBJECT IDENTIFIER ::= { id-pskc 18 }
<span class="h4"><a class="selflink" id="section-3.2.11" href="#section-3.2.11">3.2.11</a>. Time Drift</span>
The Time Drift attribute contains the device clock drift value for
time-based OTP algorithms. It is an integer, either positive or
negative, that indicates the number of time intervals that a
validation server has established that the device clock drifted after
the last successful authentication. The attribute definition is as
follows:
at-pskc-timeDrift ATTRIBUTE ::= {
TYPE INTEGER (0..MAX) IDENTIFIED BY id-pskc-timeDrift }
id-pskc-timeDrift OBJECT IDENTIFIER ::= { id-pskc 19 }
<span class="h4"><a class="selflink" id="section-3.2.12" href="#section-3.2.12">3.2.12</a>. Value MAC</span>
The Value MAC attribute is a Message Authentication Code (MAC)
generated from the encrypted value in the case that the encryption
algorithm does not support integrity checks (e.g., AES-CBC does not
provide integrity while AES Key Wrap with a message length indicator
(MLI) does). The attribute definition is as follows:
<span class="grey">Turner & Housley Standards Track [Page 13]</span><span id="page-14" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
at-pskc-valueMAC ATTRIBUTE ::= {
TYPE ValueMac IDENTIFIED BY id-pskc-valueMAC }
id-pskc-valueMAC OBJECT IDENTIFIER ::= { id-pskc 20 }
ValueMac ::= SEQUENCE {
macAlgorithm UTF8String,
mac UTF8String }
The fields in ValueMac have the following meanings:
o macAlgorithm identifies the MAC algorithm used to generate the
value placed in digest.
o mac is the base64-encoded, as specified in <a href="./rfc4648#section-4">Section 4 of [RFC4648]</a>,
mac value.
<span class="h4"><a class="selflink" id="section-3.2.13" href="#section-3.2.13">3.2.13</a>. Key User Id</span>
The Key User Id attribute indicates the user with whom the key is
associated using a distinguished name, as defined in [<a href="./rfc4514" title=""Lightweight Directory Access Protocol (LDAP): String Representation of Distinguished Names"">RFC4514</a>]. For
example, UID=jsmith,DC=example,DC=net. The attribute definition is
as follows:
at-pskc-keyUserId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyUserId }
id-pskc-keyUserId OBJECT IDENTIFIER ::= { id-pskc 27 }
As specified in [<a href="./rfc6030" title=""Portable Symmetric Key Container (PSKC)"">RFC6030</a>], there are no semantics associated with
this element, i.e., there are no checks enforcing that only a
specific user can use this key. As such, this element is for
informational purposes only.
<span class="h3"><a class="selflink" id="section-3.3" href="#section-3.3">3.3</a>. Key Policy Attributes</span>
Key policy attributes indicate a policy that can be attached to a
key. These attributes are defined in the subsections that follow.
<span class="h4"><a class="selflink" id="section-3.3.1" href="#section-3.3.1">3.3.1</a>. Key Start Date</span>
When included in sKeyAttrs, the Key Start Date attribute indicates
the start of the key's validity period. The date MUST be represented
in a form that matches the dateTime production in "canonical
representation" [<a href="#ref-XMLSCHEMA" title=""XML Schema Part 2: Datatypes Second Edition"">XMLSCHEMA</a>]. Implementations SHOULD NOT rely on time
resolution finer than milliseconds and MUST NOT generate time
instants that specify leap seconds. The attribute definition is as
follows:
<span class="grey">Turner & Housley Standards Track [Page 14]</span><span id="page-15" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
at-pskc-keyStartDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-keyStartDate }
id-pskc-keyStartDate OBJECT IDENTIFIER ::= { id-pskc 21 }
<span class="h4"><a class="selflink" id="section-3.3.2" href="#section-3.3.2">3.3.2</a>. Key Expiry Date</span>
When included in sKeyAttrs, the Key Expiry Date attribute indicates
the end of the key's validity period. The date MUST be represented
in a form that matches the dateTime production in "canonical
representation" [<a href="#ref-XMLSCHEMA" title=""XML Schema Part 2: Datatypes Second Edition"">XMLSCHEMA</a>]. Implementations SHOULD NOT rely on time
resolution finer than milliseconds and MUST NOT generate time
instants that specify leap seconds. The attribute definition is as
follows:
at-pskc-keyExpiryDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-keyExpiryDate }
id-pskc-keyExpiryDate OBJECT IDENTIFIER ::= { id-pskc 22 }
<span class="h4"><a class="selflink" id="section-3.3.3" href="#section-3.3.3">3.3.3</a>. Number of Transactions</span>
The Number of Transactions attribute indicates the maximum number of
times a key carried within the package can be used. When this
element is omitted, there is no restriction regarding the number of
times a key can be used. The attribute definition is as follows:
at-pskc-noOfTransactions ATTRIBUTE ::= {
TYPE INTEGER (0..MAX) IDENTIFIED BY id-pskc-noOfTransactions }
id-pskc-noOfTransactions OBJECT IDENTIFIER ::= { id-pskc 23 }
<span class="h4"><a class="selflink" id="section-3.3.4" href="#section-3.3.4">3.3.4</a>. Key Usage</span>
The Key Usage attribute constrains the intended usage of the key.
The recipient MUST enforce the key usage. The attribute definition
is as follows:
at-pskc-keyUsage ATTRIBUTE ::= {
TYPE PSKCKeyUsages IDENTIFIED BY id-pskc-keyUsages }
id-pskc-keyUsages OBJECT IDENTIFIER ::= { id-pskc 24 }
PSKCKeyUsages ::= SEQUENCE OF PSKCKeyUsage
PSKCKeyUsage ::= UTF8String ("OTP" | "CR" | "Encrypt" |
"Integrity" | "Verify" | "Unlock" | "Decrypt" |
"KeyWrap" | "Unwrap" | "Derive" | "Generate")
<span class="grey">Turner & Housley Standards Track [Page 15]</span><span id="page-16" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
The fields in PSKCKeyUsage have the following meanings:
o OTP: The key MUST only be used for OTP generation.
o CR: The key MUST only be used for Challenge/Response purposes.
o Encrypt: The key MUST only be used for data encryption purposes.
o Integrity: The key MUST only be used to generate a keyed message
digest for data integrity or authentication purposes.
o Verify: The key MUST only be used to verify a keyed message digest
for data integrity or authentication purposes (is the converse of
Integrity).
o Unlock: The key MUST only be used for an inverse
Challenge/Response in the case in which a user has locked the
device by entering an incorrect PIN too many times (for devices
with PIN-input capability).
o Decrypt: The key MUST only be used for data decryption purposes.
o KeyWrap: The key MUST only be used for key wrap purposes.
o Unwrap: The key MUST only be used for key unwrap purposes.
o Derive: The key MUST only be used with a key derivation function
to derive a new key (see also Section 8.2.4 of [<a href="#ref-NIST800-57" title=""NIST Special Publication 800-57, Recommendation for Key Management - Part 1: General (Revised)"">NIST800-57</a>]).
o Generate: The key MUST only be used to generate a new key based on
a random number and the previous value of the key (see also <a href="#section-8.1.5.2.1">Section</a>
<a href="#section-8.1.5.2.1">8.1.5.2.1</a> of [<a href="#ref-NIST800-57" title=""NIST Special Publication 800-57, Recommendation for Key Management - Part 1: General (Revised)"">NIST800-57</a>]).
<span class="h4"><a class="selflink" id="section-3.3.5" href="#section-3.3.5">3.3.5</a>. PIN Policy</span>
The PIN Policy attribute allows policy about the PIN usage to be
associated with the key. The attribute definition is as follows:
at-pskc-pinPolicy ATTRIBUTE ::= {
TYPE PINPolicy IDENTIFIED BY id-pskc-pinPolicy }
id-pskc-pinPolicy OBJECT IDENTIFIER ::= { id-pskc 25 }
<span class="grey">Turner & Housley Standards Track [Page 16]</span><span id="page-17" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
PINPolicy ::= SEQUENCE {
pinKeyId [0] UTF8String OPTIONAL,
pinUsageMode [1] PINUsageMode,
maxFailedAttempts [2] INTEGER (0..MAX) OPTIONAL,
minLength [3] INTEGER (0..MAX) OPTIONAL,
maxLength [4] INTEGER (0..MAX) OPTIONAL,
pinEncoding [5] Encoding OPTIONAL }
PINUsageMode ::= UTF8String ("Local" | "Prepend" | "Append" |
"Algorithmic")
The fields in PIN Policy have the following meanings:
o pinKeyId uniquely identifies the key held within this container
that contains the value of the PIN that protects the key.
o pinUsageMode indicates the way the PIN is used during the usage
of the key. The following values are defined in [<a href="./rfc6030" title=""Portable Symmetric Key Container (PSKC)"">RFC6030</a>]:
Local, Prepend, Append, and Algorithmic.
o maxFailedAttempts indicates the maximum number of times the PIN may
be entered incorrectly before it MUST NOT be possible to use the
key anymore (reasonable values are in the positive integer range of
at least 2 and no more than 10).
o minLength indicates the minimum length of a PIN that can be set to
protect the associated key. It MUST NOT be possible to set a PIN
shorter than this value. If pinEncoding is 'DECIMAL',
'HEXADECIMAL', or 'ALPHANUMERIC', this value indicates the number
of digits/ characters. If pinEncoding is 'BASE64' or 'BINARY',
this value indicates the number of bytes of the unencoded value.
o maxLength indicates the maximum length of a PIN that can be set to
protect this key. It MUST NOT be possible to set a PIN longer than
this value. If pinEncoding is 'DECIMAL', 'HEXADECIMAL', or
'ALPHANUMERIC', this value indicates the number of
digits/characters. If the pinEncoding is 'BASE64' or 'BINARY',
this value indicates the number of bytes of the unencoded value.
o pinEncoding is based on Encoding, which is defined in <a href="#section-3.2.7">Section</a>
<a href="#section-3.2.7">3.2.7</a>, and specifies encoding of the PIN and MUST be one of the
following values: DECIMAL, HEXADECIMAL, ALPHANUMERIC, BASE64, or
BINARY.
If pinUsageMode is set to "Local", then the device MUST enforce the
restriction indicated in maxFailedAttempts, minLength, maxLength, and
pinEncoding; otherwise, it MUST be enforced on the server side.
<span class="grey">Turner & Housley Standards Track [Page 17]</span><span id="page-18" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. Key Encoding</span>
Two parties receiving the same key as an sKey OCTET STRING must make
use of the key in exactly the same way in order to interoperate. To
ensure that this occurs, it is necessary to define a correspondence
between the abstract syntax of sKey and the notation in the standard
algorithm description that defines how the key is used. The next
sections establish that correspondence for the AES algorithm
[<a href="#ref-FIPS197" title=""FIPS Pub 197: Advanced Encryption Standard (AES)"">FIPS197</a>] and the Triple Data Encryption Algorithm (TDEA or Triple
DES) [<a href="#ref-SP800-67" title=""NIST Special Publication 800-67 Version 1.1: Recommendation for the Triple Data Encryption Algorithm (TDEA) Block Cipher"">SP800-67</a>].
<span class="h3"><a class="selflink" id="section-4.1" href="#section-4.1">4.1</a>. AES Key Encoding</span>
[<a href="#ref-FIPS197" title=""FIPS Pub 197: Advanced Encryption Standard (AES)"">FIPS197</a>], Section 5.2, titled "Key Expansion", uses the input key as
an array of bytes indexed starting at 0. The first octet of sKey
SHALL become the key byte in the AES, labeled index 0 in [<a href="#ref-FIPS197" title=""FIPS Pub 197: Advanced Encryption Standard (AES)"">FIPS197</a>];
the succeeding octets of sKey SHALL become key bytes in AES, in
increasing index order.
Proper parsing and key load of the contents of sKey for AES SHALL be
determined by using the following sKey OCTET STRING to generate and
match the key expansion test vectors in [<a href="#ref-FIPS197" title=""FIPS Pub 197: Advanced Encryption Standard (AES)"">FIPS197</a>], <a href="#appendix-A">Appendix A</a>, for
AES Cipher Key: 2b 7e 15 16 28 ae d2 a6 ab f7 15 88 09 cf 4f 3c
Tag Length Value
04 16 2b 7e 15 16 28 ae d2 a6 ab f7 15 88 09 cf 4f 3c
<span class="h3"><a class="selflink" id="section-4.2" href="#section-4.2">4.2</a>. Triple-DES Key Encoding</span>
A Triple-DES key consists of three keys for the cryptographic engine
(Key1, Key2, and Key3) that are each 64 bits (56 key bits and 8
parity bits); the three keys are also collectively referred to as a
key bundle [<a href="#ref-SP800-67" title=""NIST Special Publication 800-67 Version 1.1: Recommendation for the Triple Data Encryption Algorithm (TDEA) Block Cipher"">SP800-67</a>]. A key bundle may employ either two or three
independent keys. When only two independent keys are employed
(called two-key Triple DES), the same value is used for Key1 and
Key3.
Each key in a Triple-DES key bundle is expanded into a key schedule
according to a procedure defined in [<a href="#ref-SP800-67" title=""NIST Special Publication 800-67 Version 1.1: Recommendation for the Triple Data Encryption Algorithm (TDEA) Block Cipher"">SP800-67</a>], <a href="#appendix-A">Appendix A</a>. That
procedure numbers the bits in the key from 1 to 64, with number 1
being the leftmost, or most significant bit (MSB). The first octet
of sKey SHALL be bits 1 through 8 of Key1 with bit 1 being the MSB.
The second octet of sKey SHALL be bits 9 through 16 of Key1, and so
forth, so that the trailing octet of sKey SHALL be bits 57 through 64
of Key3 (or Key2 for two-key Triple DES).
<span class="grey">Turner & Housley Standards Track [Page 18]</span><span id="page-19" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
Proper parsing and key load of the contents of sKey for Triple DES
SHALL be determined by using the following sKey OCTET STRING to
generate and match the key expansion test vectors in [<a href="#ref-SP800-67" title=""NIST Special Publication 800-67 Version 1.1: Recommendation for the Triple Data Encryption Algorithm (TDEA) Block Cipher"">SP800-67</a>],
<a href="#appendix-B">Appendix B</a>, for the key bundle:
Key1 = 0123456789ABCDEF
Key2 = 23456789ABCDEF01
Key3 = 456789ABCDEF0123
Tag Length Value
04 24 0123456789ABCDEF 23456789ABCDEF01 456789ABCDEF0123
<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>. Security Considerations</span>
Implementers of this protocol are strongly encouraged to consider
generally accepted principles of secure key management when
integrating this capability within an overall security architecture.
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. One possibility is to include this content type in
place of a PSKC package in [<a href="./rfc6063" title=""Dynamic Symmetric Key Provisioning Protocol (DSKPP)"">RFC6063</a>] exchanges. In this case, the
algorithm requirements are found in those documents. Another
possibility is to encapsulate this content type in a CMS [<a href="./rfc5652" title=""Cryptographic Message Syntax (CMS)"">RFC5652</a>]
protecting content type.
<span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>. IANA Considerations</span>
This document makes use of object identifiers to identify a CMS
content type (Appendix A.1), the ASN.1 version of the PSKC attributes
(Appendix A.2), and the ASN.1 modules found in <a href="#appendix-A.1">Appendix A.1</a> and A.2.
All OIDs are registered in an arc delegated by RSADSI to the SMIME
Working Group.
<span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>. References</span>
<span class="h3"><a class="selflink" id="section-7.1" href="#section-7.1">7.1</a>. Normative References</span>
[<a id="ref-FIPS197">FIPS197</a>] National Institute of Standards. "FIPS Pub 197:
Advanced Encryption Standard (AES)", 26 November 2001.
[<a id="ref-IANAPENREG">IANAPENREG</a>] IANA, "Private Enterprise Numbers",
<<a href="http://www.iana.org">http://www.iana.org</a>>.
<span class="grey">Turner & Housley Standards Track [Page 19]</span><span id="page-20" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
[<a id="ref-ISOIEC7812">ISOIEC7812</a>] ISO, "ISO/IEC 7812-1:2006 Identification cards --
Identification of issuers -- Part 1: Numbering system",
October 2006, <<a href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=39698">http://www.iso.org/iso/iso_catalogue/</a>
<a href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=39698">catalogue_tc/catalogue_detail.htm?csnumber=39698</a>>.
[<a id="ref-OATHMAN">OATHMAN</a>] OATH, "List of OATH Manufacturer Prefixes (omp)", April
2009, <<a href="http://www.openauthentication.org/oath-id/prefixes">http://www.openauthentication.org/</a>
<a href="http://www.openauthentication.org/oath-id/prefixes">oath-id/prefixes</a>>.
[<a id="ref-RFC2119">RFC2119</a>] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", <a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a>, <a href="./rfc2119">RFC 2119</a>, March 1997.
[<a id="ref-RFC3629">RFC3629</a>] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, <a href="./rfc3629">RFC 3629</a>, November 2003.
[<a id="ref-RFC4514">RFC4514</a>] Zeilenga, K., Ed., "Lightweight Directory Access
Protocol (LDAP): String Representation of Distinguished
Names", <a href="./rfc4514">RFC 4514</a>, June 2006.
[<a id="ref-RFC4648">RFC4648</a>] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", <a href="./rfc4648">RFC 4648</a>, October 2006.
[<a id="ref-RFC5646">RFC5646</a>] Phillips, A., Ed., and M. Davis, Ed., "Tags for
Identifying Languages", <a href="https://www.rfc-editor.org/bcp/bcp47">BCP 47</a>, <a href="./rfc5646">RFC 5646</a>, September
2009.
[<a id="ref-RFC5911">RFC5911</a>] Hoffman, P. and J. Schaad, "New ASN.1 Modules for
Cryptographic Message Syntax (CMS) and S/MIME", <a href="./rfc5911">RFC</a>
<a href="./rfc5911">5911</a>, June 2010.
[<a id="ref-RFC5912">RFC5912</a>] Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
Public Key Infrastructure Using X.509 (PKIX)", <a href="./rfc5912">RFC 5912</a>,
June 2010.
[<a id="ref-RFC6019">RFC6019</a>] Housley, R., "BinaryTime: An Alternate Format for
Representing Date and Time in ASN.1", <a href="./rfc6019">RFC 6019</a>,
September 2010.
[<a id="ref-RFC6030">RFC6030</a>] Hoyer, P., Pei, M., and S. Machani, "Portable Symmetric
Key Container (PSKC)", <a href="./rfc6030">RFC 6030</a>, October 2010.
[<a id="ref-SP800-67">SP800-67</a>] National Institute of Standards and Technology, "NIST
Special Publication 800-67 Version 1.1: Recommendation
for the Triple Data Encryption Algorithm (TDEA) Block
Cipher", NIST Special Publication 800-67, May 2008.
<span class="grey">Turner & Housley Standards Track [Page 20]</span><span id="page-21" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
[<a id="ref-X.680">X.680</a>] ITU-T Recommendation X.680 (2002) | ISO/IEC 8824-
1:2002. Information Technology - Abstract Syntax
Notation One.
[<a id="ref-X.681">X.681</a>] ITU-T Recommendation X.681 (2002) | ISO/IEC 8824-
2:2002. Information Technology - Abstract Syntax
Notation One: Information Object Specification.
[<a id="ref-X.682">X.682</a>] ITU-T Recommendation X.682 (2002) | ISO/IEC 8824-
3:2002. Information Technology - Abstract Syntax
Notation One: Constraint Specification.
[<a id="ref-X.683">X.683</a>] ITU-T Recommendation X.683 (2002) | ISO/IEC 8824-
4:2002. Information Technology - Abstract Syntax
Notation One: Parameterization of ASN.1 Specifications.
[<a id="ref-X.690">X.690</a>] 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).
[<a id="ref-XMLSCHEMA">XMLSCHEMA</a>] Malhotra, A. and P. Biron, "XML Schema Part 2: Datatypes
Second Edition", World Wide Web Consortium
Recommendation REC-xmlschema-2-20041082, October 2004,
<<a href="http://www.w3.org/TR/2004/REC-xmlschema-2-20041028">http://www.w3.org/TR/2004/REC-xmlschema-2-20041028</a>>.
<span class="h3"><a class="selflink" id="section-7.2" href="#section-7.2">7.2</a>. Informative References</span>
[<a id="ref-NIST800-57">NIST800-57</a>] National Institute of Standards and Technology, "NIST
Special Publication 800-57, Recommendation for Key
Management - Part 1: General (Revised)", NIST Special
Publication 800-57, March 2007.
[<a id="ref-RFC5652">RFC5652</a>] Housley, R., "Cryptographic Message Syntax (CMS)", STD
70, <a href="./rfc5652">RFC 5652</a>, September 2009.
[<a id="ref-RFC6063">RFC6063</a>] Doherty, A., Pei, M., Machani, S., and M. Nystrom,
"Dynamic Symmetric Key Provisioning Protocol (DSKPP)",
<a href="./rfc6063">RFC 6063</a>, December 2010.
<span class="grey">Turner & Housley Standards Track [Page 21]</span><span id="page-22" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
<span class="h2"><a class="selflink" id="appendix-A" href="#appendix-A">Appendix A</a>. ASN.1 Module</span>
This appendix provides the normative ASN.1 definitions for the
structures described in this specification using ASN.1 as defined in
[<a href="#ref-X.680">X.680</a>], [<a href="#ref-X.681">X.681</a>], [<a href="#ref-X.682">X.682</a>], and [<a href="#ref-X.683">X.683</a>].
<span class="h3"><a class="selflink" id="appendix-A.1" href="#appendix-A.1">A.1</a>. Symmetric Key Package ASN.1 Module</span>
SymmetricKeyPackageModulev1
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) id-mod-symmetricKeyPkgV1(33) }
DEFINITIONS IMPLICIT TAGS ::=
BEGIN
-- EXPORTS ALL
IMPORTS
-- From New PKIX ASN.1 [<a href="./rfc5912" title=""New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)"">RFC5912</a>]
ATTRIBUTE
FROM PKIX-CommonTypes-2009
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkixCommon-02(57) }
-- From New SMIME ASN.1 [<a href="./rfc5911" title=""New ASN.1 Modules for Cryptographic Message Syntax (CMS) and S/MIME"">RFC5911</a>]
CONTENT-TYPE, Attribute{}
FROM CryptographicMessageSyntax-2009
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) id-mod-cms-2004-02(41) }
;
ContentSet CONTENT-TYPE ::= {
ct-symmetric-key-package,
... -- Expect additional content types --
}
ct-symmetric-key-package CONTENT-TYPE ::=
{ 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 }
<span class="grey">Turner & Housley Standards Track [Page 22]</span><span id="page-23" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
SymmetricKeyPackage ::= SEQUENCE {
version KeyPkgVersion DEFAULT v1,
sKeyPkgAttrs [0] SEQUENCE SIZE (1..MAX) OF Attribute
{{ SKeyPkgAttributes }} OPTIONAL,
sKeys SymmetricKeys,
... }
SymmetricKeys ::= SEQUENCE SIZE (1..MAX) OF OneSymmetricKey
OneSymmetricKey ::= SEQUENCE {
sKeyAttrs SEQUENCE SIZE (1..MAX) OF Attribute
{{ SKeyAttributes }} OPTIONAL,
sKey OCTET STRING OPTIONAL }
( WITH COMPONENTS { ..., sKeyAttrs PRESENT } |
WITH COMPONENTS { ..., sKey PRESENT } )
KeyPkgVersion ::= INTEGER { v1(1) } ( v1, ... )
SKeyPkgAttributes ATTRIBUTE ::= { ... }
SKeyAttributes ATTRIBUTE ::= { ... }
END
<span class="h3"><a class="selflink" id="appendix-A.2" href="#appendix-A.2">A.2</a>. PSKC ASN.1 Module</span>
PSKCAttributesModule
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) id-mod-pskcAttributesModule(53) }
DEFINITIONS IMPLICIT TAGS ::=
BEGIN
-- EXPORTS ALL
IMPORTS
-- From New PKIX ASN.1 [<a href="./rfc5912" title=""New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)"">RFC5912</a>]
ATTRIBUTE
FROM PKIX-CommonTypes-2009
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkixCommon-02(57) }
<span class="grey">Turner & Housley Standards Track [Page 23]</span><span id="page-24" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
-- From BinaryTime [<a href="./rfc6019" title=""BinaryTime: An Alternate Format for Representing Date and Time in ASN.1"">RFC6019</a>]
BinaryTime
FROM BinarySigningTimeModule
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) id-mod-binarySigningTime(27) }
-- From New SMIME ASN.1 [<a href="./rfc5911" title=""New ASN.1 Modules for Cryptographic Message Syntax (CMS) and S/MIME"">RFC5911</a>]
id-smime
FROM SecureMimeMessageV3dot1-2009
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) id-mod-msg-v3dot1-02(39) }
;
--
-- PSKC Attributes OIDs are taken from the SMIME Arc.
--
id-pskc OBJECT IDENTIFIER ::= { id-smime 12 }
--
-- Merge SKeyPKGAttributes to the set of attributes for sKeyPkgAttrs
--
SKeyPkgAttributes ATTRIBUTE ::= {
at-pskc-manufacturer | at-pskc-serialNo | at-pskc-model |
at-pskc-issueNo | at-pskc-deviceBinding |
at-pskc-deviceStartDate | at-pskc-deviceExpiryDate |
at-pskc-moduleId | at-pskc-deviceUserId, ... }
--
-- Merge SKeyAttributes to the set of attributes for sKeyAttrs
--
SKeyAttributes ATTRIBUTE ::= {
at-pskc-keyId | at-pskc-algorithm | at-pskc-issuer |
at-pskc-keyProfileId | at-pskc-keyReference |
at-pskc-friendlyName | at-pskc-algorithmParameters |
at-pskc-counter | at-pskc-time | at-pskc-timeInterval |
at-pskc-timeDrift | at-pskc-valueMAC | at-pskc-keyUserId |
at-pskc-keyStartDate | at-pskc-keyExpiryDate |
at-pskc-numberOfTransactions | at-pskc-keyUsage |
at-pskc-pinPolicy, ... }
at-pskc-manufacturer ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-manufacturer }
<span class="grey">Turner & Housley Standards Track [Page 24]</span><span id="page-25" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
id-pskc-manufacturer OBJECT IDENTIFIER ::= { id-pskc 1 }
at-pskc-serialNo ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-serialNo }
id-pskc-serialNo OBJECT IDENTIFIER ::= { id-pskc 2 }
at-pskc-model ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-model }
id-pskc-model OBJECT IDENTIFIER ::= { id-pskc 3 }
at-pskc-issueNo ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-issueNo }
id-pskc-issueNo OBJECT IDENTIFIER ::= { id-pskc 4 }
at-pskc-deviceBinding ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-deviceBinding }
id-pskc-deviceBinding OBJECT IDENTIFIER ::= { id-pskc 5 }
at-pskc-deviceStartDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-deviceStartDate }
id-pskc-deviceStartDate OBJECT IDENTIFIER ::= { id-pskc 6 }
at-pskc-deviceExpiryDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-deviceExpiryDate }
id-pskc-deviceExpiryDate OBJECT IDENTIFIER ::= { id-pskc 7 }
at-pskc-moduleId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-moduleId }
id-pskc-moduleId OBJECT IDENTIFIER ::= { id-pskc 8 }
at-pskc-deviceUserId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-deviceUserId }
id-pskc-deviceUserId OBJECT IDENTIFIER ::= { id-pskc 26 }
at-pskc-keyId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyId }
id-pskc-keyId OBJECT IDENTIFIER ::= { id-pskc 9 }
<span class="grey">Turner & Housley Standards Track [Page 25]</span><span id="page-26" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
at-pskc-algorithm ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-algorithm }
id-pskc-algorithm OBJECT IDENTIFIER ::= { id-pskc 10 }
at-pskc-issuer ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-issuer }
id-pskc-issuer OBJECT IDENTIFIER ::= { id-pskc 11 }
at-pskc-keyProfileId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyProfileId }
id-pskc-keyProfileId OBJECT IDENTIFIER ::= { id-pskc 12 }
at-pskc-keyReference ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyReference }
id-pskc-keyReference OBJECT IDENTIFIER ::= { id-pskc 13 }
at-pskc-friendlyName ATTRIBUTE ::= {
TYPE FriendlyName IDENTIFIED BY id-pskc-friendlyName }
id-pskc-friendlyName OBJECT IDENTIFIER ::= { id-pskc 14 }
FriendlyName ::= SEQUENCE {
friendlyName UTF8String,
friendlyNameLangTag UTF8String OPTIONAL }
at-pskc-algorithmParameters ATTRIBUTE ::= {
TYPE PSKCAlgorithmParameters
IDENTIFIED BY id-pskc-algorithmParameters }
id-pskc-algorithmParameters OBJECT IDENTIFIER ::= { id-pskc 15 }
PSKCAlgorithmParameters ::= CHOICE {
suite UTF8String,
challengeFormat [0] ChallengeFormat,
responseFormat [1] ResponseFormat,
... }
ChallengeFormat ::= SEQUENCE {
encoding Encoding,
checkDigit BOOLEAN DEFAULT FALSE,
min INTEGER (0..MAX),
max INTEGER (0..MAX),
... }
<span class="grey">Turner & Housley Standards Track [Page 26]</span><span id="page-27" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
Encoding ::= UTF8String ("DECIMAL" | "HEXADECIMAL" |
"ALPHANUMERIC" | "BASE64" | "BINARY" )
ResponseFormat ::= SEQUENCE {
encoding Encoding,
length INTEGER (0..MAX),
checkDigit BOOLEAN DEFAULT FALSE,
... }
at-pskc-counter ATTRIBUTE ::= {
TYPE INTEGER (0..MAX) IDENTIFIED BY id-pskc-counter }
id-pskc-counter OBJECT IDENTIFIER ::= { id-pskc 16 }
at-pskc-time ATTRIBUTE ::= {
TYPE BinaryTime IDENTIFIED BY id-pskc-time }
id-pskc-time OBJECT IDENTIFIER ::= { id-pskc 17 }
at-pskc-timeInterval ATTRIBUTE ::= {
TYPE INTEGER (0..MAX) IDENTIFIED BY id-pskc-timeInterval }
id-pskc-timeInterval OBJECT IDENTIFIER ::= { id-pskc 18 }
at-pskc-timeDrift ATTRIBUTE ::= {
TYPE INTEGER (0..MAX) IDENTIFIED BY id-pskc-timeDrift }
id-pskc-timeDrift OBJECT IDENTIFIER ::= { id-pskc 19 }
at-pskc-valueMAC ATTRIBUTE ::= {
TYPE ValueMac IDENTIFIED BY id-pskc-valueMAC }
id-pskc-valueMAC OBJECT IDENTIFIER ::= { id-pskc 20 }
ValueMac ::= SEQUENCE {
macAlgorithm UTF8String,
mac UTF8String }
at-pskc-keyUserId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyUserId }
id-pskc-keyUserId OBJECT IDENTIFIER ::= { id-pskc 27 }
at-pskc-keyStartDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-keyStartDate }
id-pskc-keyStartDate OBJECT IDENTIFIER ::= { id-pskc 21 }
<span class="grey">Turner & Housley Standards Track [Page 27]</span><span id="page-28" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
at-pskc-keyExpiryDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-keyExpiryDate }
id-pskc-keyExpiryDate OBJECT IDENTIFIER ::= { id-pskc 22 }
at-pskc-numberOfTransactions ATTRIBUTE ::= {
TYPE INTEGER (0..MAX) IDENTIFIED BY id-pskc-numberOfTransactions }
id-pskc-numberOfTransactions OBJECT IDENTIFIER ::= { id-pskc 23 }
at-pskc-keyUsage ATTRIBUTE ::= {
TYPE PSKCKeyUsages IDENTIFIED BY id-pskc-keyUsages }
id-pskc-keyUsages OBJECT IDENTIFIER ::= { id-pskc 24 }
PSKCKeyUsages ::= SEQUENCE OF PSKCKeyUsage
PSKCKeyUsage ::= UTF8String ("OTP" | "CR" | "Encrypt" |
"Integrity" | "Verify" | "Unlock" | "Decrypt" |
"KeyWrap" | "Unwrap" | "Derive" | "Generate")
at-pskc-pinPolicy ATTRIBUTE ::= {
TYPE PINPolicy IDENTIFIED BY id-pskc-pinPolicy }
id-pskc-pinPolicy OBJECT IDENTIFIER ::= { id-pskc 25 }
PINPolicy ::= SEQUENCE {
pinKeyId [0] UTF8String OPTIONAL,
pinUsageMode [1] PINUsageMode,
maxFailedAttempts [2] INTEGER (0..MAX) OPTIONAL,
minLength [3] INTEGER (0..MAX) OPTIONAL,
maxLength [4] INTEGER (0..MAX) OPTIONAL,
pinEncoding [5] Encoding OPTIONAL }
PINUsageMode ::= UTF8String ("Local" | "Prepend" | "Append"|
"Algorithmic")
END
<span class="grey">Turner & Housley Standards Track [Page 28]</span><span id="page-29" ></span>
<span class="grey"><a href="./rfc6031">RFC 6031</a> CMS Symmetric Key Package Content Type December 2010</span>
Authors' Addresses
Sean Turner
IECA, Inc.
3057 Nutley Street, Suite 106
Fairfax, VA 22031
USA
EMail: [email protected]
Russell Housley
Vigil Security, LLC
918 Spring Knoll Drive
Herndon, VA 20170
USA
EMail: [email protected]
Turner & Housley Standards Track [Page 29]
Annotations
Select text to annotate