Internet DRAFT - draft-ietf-keyprov-portable-symmetric-key-container
draft-ietf-keyprov-portable-symmetric-key-container
keyprov P. Hoyer
Internet-Draft ActivIdentity
Intended status: Standards Track M. Pei
Expires: May 7, 2009 VeriSign
S. Machani
Diversinet
November 03, 2008
Portable Symmetric Key Container
draft-ietf-keyprov-portable-symmetric-key-container-06.txt
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Abstract
This document specifies a symmetric key format for transport and
provisioning of symmetric keys (for example One Time Password (OTP)
shared secrets or symmetric cryptographic keys) to different types of
crypto modules such as a strong authentication device. The standard
key transport format enables enterprises to deploy best-of-breed
solutions combining components from different vendors into the same
infrastructure.
This work is based on earlier work by the members of OATH (Initiative
for Open AuTHentication) to specify a format that can be freely
distributed to the technical community. The authors believe that a
common and shared specification will facilitate adoption of two-
factor authentication on the Internet by enabling interoperability
between commercial and open-source implementations.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 6
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Online Use Cases . . . . . . . . . . . . . . . . . . . . . 8
3.1.1. Transport of keys from Server to Cryptographic
Module . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.2. Transport of keys from Cryptographic Module to
Cryptographic Module . . . . . . . . . . . . . . . . . 8
3.1.3. Transport of keys from Cryptographic Module to
Server . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1.4. Server to server Bulk import/export of keys . . . . . 9
3.2. Offline Use Cases . . . . . . . . . . . . . . . . . . . . 9
3.2.1. Server to server Bulk import/export of keys . . . . . 9
4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. Portable Key container definition . . . . . . . . . . . . . . 13
5.1. KeyContainer . . . . . . . . . . . . . . . . . . . . . . . 14
5.2. KeyProperties . . . . . . . . . . . . . . . . . . . . . . 15
5.3. Device . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.3.1. DeviceInfo . . . . . . . . . . . . . . . . . . . . . . 18
5.4. Key . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.4.1. KeyData . . . . . . . . . . . . . . . . . . . . . . . 23
5.4.2. Usage . . . . . . . . . . . . . . . . . . . . . . . . 25
5.4.3. ValueFormat . . . . . . . . . . . . . . . . . . . . . 29
5.4.4. PINPolicy . . . . . . . . . . . . . . . . . . . . . . 29
6. Usage and profile of algorithms for the portable symmetric
key container . . . . . . . . . . . . . . . . . . . . . . . . 33
6.1. Usage of EncryptionKey to protect keys in transit . . . . 33
6.1.1. Protecting keys using a pre-shared key via
symmetric algorithms . . . . . . . . . . . . . . . . . 33
6.1.2. Protecting keys using passphrase based key
encryption keys . . . . . . . . . . . . . . . . . . . 35
6.2. Protecting keys using asymmetric algorithms . . . . . . . 38
6.3. Profile of Key Algorithm . . . . . . . . . . . . . . . . . 39
6.3.1. OTP Key Algorithm Identifiers . . . . . . . . . . . . 40
6.3.2. PIN key value compare algorithm identifier . . . . . . 40
7. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 41
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 48
8.1. Content-type registration for 'application/pskc+xml' . . . 48
8.2. XML Schema Registration . . . . . . . . . . . . . . . . . 49
8.3. URN Sub-Namespace Registration for
urn:ietf:params:xml:ns:keyprov:pskc:1.0 . . . . . . . . . 49
8.4. Symmetric Key Algorithm Identifier Registry . . . . . . . 50
8.4.1. Applicability . . . . . . . . . . . . . . . . . . . . 50
8.4.2. Registerable Algorithms . . . . . . . . . . . . . . . 51
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8.4.3. Registration Procedures . . . . . . . . . . . . . . . 52
8.4.4. Initial Values . . . . . . . . . . . . . . . . . . . . 54
9. Security Considerations . . . . . . . . . . . . . . . . . . . 76
9.1. Payload confidentiality . . . . . . . . . . . . . . . . . 76
9.2. Payload integrity . . . . . . . . . . . . . . . . . . . . 77
9.3. Payload authenticity . . . . . . . . . . . . . . . . . . . 77
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 78
11. Appendix A - Example Symmetric Key Containers . . . . . . . . 79
11.1. Symmetric Key Container with a single Non-Encrypted
HOTP Secret Key . . . . . . . . . . . . . . . . . . . . . 79
11.2. Symmetric Key Container with a single PIN protected
Non-Encrypted HOTP Secret Key . . . . . . . . . . . . . . 80
11.3. Symmetric Key Container with a single AES-128-CBC
Encrypted HOTP Secret Key and non-encrypted counter
value . . . . . . . . . . . . . . . . . . . . . . . . . . 82
11.4. Symmetric Key Container with signature and a single
Password-based Encrypted HOTP Secret Key . . . . . . . . . 83
11.5. Symmetric Key Container with a single RSA 1.5
Encrypted HOTP Secret Key . . . . . . . . . . . . . . . . 85
11.6. Symmetric Key Container with a single AES-128-CBC
Encrypted OCRA Secret Key and non-encrypted counter
value . . . . . . . . . . . . . . . . . . . . . . . . . . 86
11.7. Symmetric Key Container with a single AES-256-CBC
Encrypted TOTP Secret Key and non-encrypted time values . 88
11.8. Symmetric Key Container with two devices containing a
Non-Encrypted HOTP Secret Key each sharing common
KeyProperties . . . . . . . . . . . . . . . . . . . . . . 90
12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 92
12.1. Normative References . . . . . . . . . . . . . . . . . . . 92
12.2. Informative References . . . . . . . . . . . . . . . . . . 93
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 94
Intellectual Property and Copyright Statements . . . . . . . . . . 95
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1. Introduction
With increasing use of symmetric key based authentication systems
such as systems based one time password (OTP) and challenge response
mechanisms, there is a need for vendor interoperability and a
standard format for importing, exporting or provisioning symmetric
keys from one system to another. Traditionally authentication server
vendors and service providers have used proprietary formats for
importing, exporting and provisioning these keys into their systems
making it hard to use tokens from vendor A with a server from vendor
B.
This document describes a standard format for serializing symmetric
keys such as OTP shared secrets for system import, export or network/
protocol transport. The goal is that the format will facilitate
dynamic provisioning and transfer of symmetric keys such as OTP
shared secrets or encryption keys of different types. In the case of
OTP shared secrets, the format will facilitate dynamic provisioning
using an online provisioning protocol to different flavors of
embedded tokens or allow customers to import new or existing tokens
in batch or single instances into a compliant system.
This draft also specifies the key attributes required for computation
such as the initial event counter used in the HOTP algorithm [HOTP].
It is also applicable for other time-based or proprietary algorithms.
To provide an analogy, in public key environments the PKCS#12 format
[PKCS12] is commonly used for importing and exporting private keys
and certificates between systems. In the environments outlined in
this document where OTP keys may be transported directly down to
smartcards or devices with limited computing capabilities and
explicit shared secret, configuration attribute information is
desirable. With PKCS#12, one would have to use opaque data to carry
shared secret attributes used for OTP calculations, whereas a more
explicit attribute schema definition is better for interoperability
and efficiency.
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2. Terminology
2.1. Key Words
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].
2.2. Definitions
This section defines terms used in this document. The same terms may
be defined differently in other documents.
Authentication Token: A physical device that an authorized user of
computer services is given to aid in authentication. The term may
also refer to software tokens.
Bulk Provisioning: Transferring multiple keys linked to multiple
devices in a single execution step within one single PSKC
KeyContainer
Cryptographic Module: A component of an application, which enables
symmetric key cryptographic functionality
Cryptographic Key: A parameter used in conjunction with a
cryptographic algorithm that determines its operation in such a
way that an entity with knowledge of the key can reproduce or
reverse the operation, while an entity without knowledge of the
key cannot (see [NIST-SP800-57])
Cryptographic Token: See Authentication Token
Device: A physical piece of hardware, or a software framework, that
hosts symmetric keys
DeviceInfo: A set of elements whose values combined uniquely
identify a device e.g. Manufacturer 'TokenVendorAcme' and
Serialnumber '12345678'
Dynamic Provisioning: Usage of a protocol, such as DSKPP, to make a
key container available to a recipient
Key Encryption Key: A key used to encrypt key
Key: See Cryptographic Key
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Hardware Token: See Authentication Token
Key Algorithm: A well-defined computational procedure that takes
variable inputs including a cryptographic key and produces an
output.
Key Container: An object that encapsulates symmetric keys and their
attributes for set of devices
Key ID (KeyID): A unique identifier for the symmetric key
Key Issuer: An organization that issues symmetric keys to end-users
Key Type: The type of symmetric key cryptographic methods for which
the key will be used (e.g., OATH HOTP or RSA SecurID
authentication, AES encryption, etc.)
Secret Key: The symmetric key data
Software Token: A type of authentication token that is stored on a
general-purpose electronic device such as a desktop computer,
laptop, PDA, or mobile phone
Token: See Authentication Token
User: The person or client to whom devices are issued
User ID: A unique identifier for the user or client
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3. Use Cases
This section describes a comprehensive list of use cases that
inspired the development of this specification. These requirements
were used to derive the primary requirement that drove the design.
These requirements are covered in the next section.
These use cases also help in understanding the applicability of this
specification to real world situations.
3.1. Online Use Cases
This section describes the use cases related to provisioning the keys
using an online provisioning protocol such as [DSKPP]
3.1.1. Transport of keys from Server to Cryptographic Module
For example, a mobile device user wants to obtain a symmetric key for
use with a Cryptographic Module on the device. The Cryptographic
Module 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 Cryptographic Module 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.
3.1.2. Transport of keys from Cryptographic Module to Cryptographic
Module
For example, a user wants to transport a key from one Cryptographic
Module 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
Cryptographic Module.
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3.1.3. Transport of keys from Cryptographic Module 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 Cryptographic Module (e.g. SD card, USB
drive) that the user has purchased at the local electronics retailer.
Along with the Cryptographic Module, 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.
3.1.4. 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 Over-The-Aire (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.
3.2. 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.
3.2.1. Server to server Bulk import/export of keys
For example, Cryptographic Modules 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.
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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
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.
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4. Requirements
This section outlines the most relevant requirements that are the
basis of this work. Several of the requirements were derived from
use cases described above.
R1: The format MUST support transport of multiple types of
symmetric keys and related attributes for algorithms including
HOTP, other OTP, challenge-response, etc.
R2: The format MUST handle the symmetric key itself as well of
attributes that are typically associated with symmetric keys.
Some of these attributes may be
* Unique Key Identifier
* Issuer information
* Algorithm ID
* Algorithm mode
* Issuer Name
* Key friendly name
* Event counter value (moving factor for OTP algorithms)
* Time value
R3: The format SHOULD support both offline and online scenarios.
That is it should be serializable to a file as well as it
should be possible to use this format in online provisioning
protocols such as [DSKPP]
R4: The format SHOULD allow bulk representation of symmetric keys
R5: The format SHOULD allow bulk representation of PINs related to
specific keys
R6: The format SHOULD be portable to various platforms.
Furthermore, it SHOULD be computationally efficient to process.
R7: The format MUST provide appropriate level of security in terms
of data encryption and data integrity.
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R8: For online scenarios the format SHOULD NOT rely on transport
level security (e.g., SSL/TLS) for core security requirements.
R9: The format SHOULD be extensible. It SHOULD enable extension
points allowing vendors to specify additional attributes in the
future.
R10: The format SHOULD allow for distribution of key derivation data
without the actual symmetric key itself. This is to support
symmetric key management schemes that rely on key derivation
algorithms based on a pre-placed master key. The key
derivation data typically consists of a reference to the key,
rather than the key value itself.
R11: The format SHOULD allow for additional lifecycle management
operations such as counter resynchronization. Such processes
require confidentiality between client and server, thus could
use a common secure container format, without the transfer of
key material.
R12: The format MUST support the use of pre-shared symmetric keys to
ensure confidentiality of sensitive data elements.
R13: The format MUST support a password-based encryption (PBE)
[PKCS5] scheme to ensure security of sensitive data elements.
This is a widely used method for various provisioning
scenarios.
R14: The format SHOULD support asymmetric encryption algorithms such
as RSA to ensure end-to-end security of sensitive data
elements. This is to support scenarios where a pre-set shared
key encryption key is difficult to use.
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5. Portable Key container definition
The portable key container is based on an XML schema definition and
contains the following main entities:
1. KeyContainer entity as defined in Section 5.1
2. KeyProperties entity as defined in Section 5.2
3. Device entity as defined in Section 5.3
4. Key entity as defined in Section 5.4
Additionally other XML schema types have been defined and are
detailed in the relevant subsections of this document
A KeyContainer MAY contain one or more Device entities. A Device MAY
contain one or more Key entities
The figure below indicates a possible relationship diagram of a
container.
--------------------------------------------
| KeyContainer |
| |
| -------------------- |
| | Keyproperties 1 | |
| | | |
| -------------------- |
| ------------------ ----------------- |
| | Device 1 | | Device n | |
| | | | | |
| | ------------ | | ------------ | |
| | | Key 1 | | | | Key n | | |
| | ------------ | | ------------ | |
| | | | | |
| | | | | |
| | ------------ | | ------------ | |
| | | Key m | | | | Key p | | |
| | ------------ | | ------------ | |
| ------------------ ----------------- |
| |
--------------------------------------------
The following sections describe in detail all the entities and
related XML schema elements and attributes:
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5.1. KeyContainer
The KeyContainer represents the key container entity. A Container
MAY contain more than one Device entity; each Device entity MAY
contain more than one Key entity.
The KeyContainer is defined as follows:
<xs:complexType name="KeyContainerType">
<xs:sequence>
<xs:element name="EncryptionKey"
type="ds:KeyInfoType" minOccurs="0"/>
<xs:element name="MACAlgorithm"
type="pskc:KeyAlgorithmType" minOccurs="0"/>
<xs:element name="KeyProperties"
type="pskc:KeyPropertiesType" minOccurs="0"
maxOccurs="unbounded"/>
<xs:element name="Device"
type="pskc:DeviceType" minOccurs="1"
maxOccurs="unbounded"/>
<xs:element name="Signature"
type="ds:SignatureType" minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="Version" type="pskc:VersionType"
use="required"/>
<xs:attribute ref="xml:id" use="optional"/>
</xs:complexType>
The attributes of the KeyContainer have the following meanings:
o Version (MANDATORY), the version number for the portable key
container format (the XML schema defined in this document).
o ID (OPTIONAL), the unique ID for this container in case an XML
document contains more than one container and wants to refer to
them uniquely.
The elements of the KeyContainer have the following meanings:
o <EncryptionKey> (OPTIONAL), Identifies the key encryption key,
algorithm and possible parameters used to protect the Secret Key
data in the container. Please see Section 6.1 for detailed
description of how to protect key data in transit and the usage of
this element.
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o <MACAlgorithm> (OPTIONAL), Identifies the algorithm used to
generate a Message Authentication Code (MAC) of the Secret Key
data values when protection algorithms are used that do not have
integrity checks. The digest guarantees the integrity and the
authenticity of the key data. for profile and usage please see
Section 6.1.1
o <KeyProperties> (OPTIONAL), key property entities containing key
related properties that are common for keys within this container.
Please see Section 5.2 for detailed description of this
element.The KeyContainer MAY contain multiple KeyProperties
elements each containing a set of properties related to one or
more keys transported within the container.
o <Device> (MANDATORY), the host Device for one or more Keys as
defined in Section 5.3 The KeyContainer MAY contain multiple
Device data elements, allowing for bulk provisioning of multiple
devices each containing multiple keys.
o <Signature> (OPTIONAL), the signature value of the Container.
When the signature is applied to the entire container, it MUST use
XML Signature methods as defined in [XMLDSIG]. It MAY be omitted
when application layer provisioning or transport layer
provisioning protocols provide the integrity and authenticity of
the payload between the sender and the recipient of the container.
When required, this specification recommends using a symmetric key
based signature with the same key used in the encryption of the
secret key data. The signature is enveloped.
o <Extensions> (OPTIONAL), is the extension point for this entity.
All extensions are grouped under this element and will be of type
pskc:ExtensionType, which contains an optional attribute
'definition' that can have a URI pointing at the defintion of the
extension. In this way groups of extension can be bundled under a
subelement. For example:
<Extensions>
<MyExtension1 xmlns="http://ACME/MyExtension.xsd">blah</MyExtension1>
<YourExtension99 xmlns="http://ACME/YourExtension.xsd">blahblah
</YourExtension99>
</Extensions>
5.2. KeyProperties
The KeyProperties represents common properties shared by more than
one key held in the container. If a value is set in the properties
the Key element can refer to it via ID attribute. Values that are
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present in the Key element itself MUST take precedence over values
set in KeyProperties. The KeyProperties is defined as follows:
<xs:complexType name="KeyPropertiesType">
<xs:sequence>
<xs:element name="Issuer" type="xs:string"
minOccurs="0"/>
<xs:element name="Usage" type="pskc:UsageType"
minOccurs="0"/>
<xs:element name="KeyProfileId" type="xs:string"
minOccurs="0"/>
<xs:element name="MasterKeyId" type="xs:string"
minOccurs="0"/>
<xs:element name="Data" type="pskc:KeyDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="PINPolicy"
type="pskc:PINPolicyType" minOccurs="0"/>
<xs:element name="StartDate" type="xs:dateTime"
minOccurs="0"/>
<xs:element name="ExpiryDate"
type="xs:dateTime" minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute ref="xml:id" use="required"/>
<xs:attribute name="KeyAlgorithm"
type="pskc:KeyAlgorithmType" use="required"/>
</xs:complexType>
The attributes of the KeyProperties entity have the following
meanings:
o ID (MANDATORY), a unique and global identifier of set of
KeyProperties. The identifier is defined as a string of
alphanumeric characters.
o KeyAlgorithm (MANDATORY), the unique URI of the type of algorithm
to use with a secret key for the profiles described in Section 6.3
Since KeyProperties are a method to group element values that are
common to multiple keys transported, please refer to Section 5.4 for
detailed description of all elements.
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5.3. Device
The Device represents an extensible Device entity in the Container.
A Device MAY be bound to a user and MAY contain more than one key. A
key SHOULD be bound to only one Device.
The Device is defined as follows:
<xs:complexType name="DeviceType">
<xs:sequence>
<xs:element name="DeviceInfo" type="pskc:DeviceInfoType"
minOccurs="0"/>
<xs:element name="Key" type="pskc:KeyType"
maxOccurs="unbounded"/>
<xs:element name="User" type="xs:string" minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
The elements of the Device have the following meanings:
o <DeviceInfo> (OPTIONAL), a set of elements containing information
about the device, whose values uniquely identify the device,
defined in Section 5.3.1
o <Key> (MANDATORY), represents the key entity as defined in
Section 5.4
o <User> (OPTIONAL), identifies the owner or the user of the Device,
a string representation of a Distinguished Name as defined in
[RFC4514]. For example UID=jsmith,DC=example,DC=net. In systems
where unique user Ids are used the string representation
'UID=[uniqueId]' SHOULD be used.
o <Extensions> (OPTIONAL), is the extension point for this entity.
All extensions are grouped under this element and will be of type
pskc:ExtensionType, which contains an optional attribute
'defintion' that can have a URI pointing at the defintion of the
extension. In this way groups of extension can be bundled under a
subelement. For example:
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<Extensions>
<MyExtension1 xmlns="http://ACME/MyExtension.xsd">blah</MyExtension1>
<YourExtension99 xmlns="http://ACME/YourExtension.xsd">blahblah
</YourExtension99>
</Extensions>
5.3.1. DeviceInfo
The DeviceInfo represents an extensible set of elements that form the
identifying criteria to uniquely identify the device that contains
the associated keys. Since devices can come in different form
factors such as hardware tokens, smart-cards, soft tokens in a mobile
phone or PC etc this element allows different criteria to be used.
Combined though the criteria MUST uniquely identify the device. For
example for hardware tokens the combination of SerialNo and
Manufacturer will uniquely identify a device but not SerialNo alone
since two different token manufacturers might issue devices with the
same serial number (similar to the IssuerDN and serial number of a
certificate). Symmetric Keys used in the payment industry are
usually stored on Integrated Circuit Smart Cards. These cards are
uniquely identified via the Primary Account Number (PAN, the long
number printed on the front of the card) and an expiry date of the
card. DeviceInfo is an extensible type that allows all these
different ways to uniquely identify a specific key containing device.
The DeviceInfo is defined as follows:
<xs:complexType name="DeviceInfoType">
<xs:sequence>
<xs:element name="Manufacturer" type="xs:string"/>
<xs:element name="SerialNo" type="xs:string"/>
<xs:element name="Model" type="xs:string" minOccurs="0"/>
<xs:element name="IssueNo" type="xs:string" minOccurs="0"/>
<xs:element name="DeviceBinding" type="xs:string" minOccurs="0"/>
<xs:element name="StartDate" type="xs:dateTime" minOccurs="0"/>
<xs:element name="ExpiryDate" type="xs:dateTime" minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
The elements of DeviceInfo have the following meanings:
o <Manufacturer> (MANDATORY), the manufacturer of the device.
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o <SerialNo> (MANDATORY), the serial number of the device or the PAN
(primary account number) in case of payment smart cards.
o <Model> (OPTIONAL), the model of the device (e.g. one-button-HOTP-
token-V1)
o <IssueNo> (OPTIONAL), the issue number in case of smart cards with
the same PAN, equivalent to a PSN (PAN Sequence Number).
o <DeviceBinding> (OPTIONAL), the identifier that can be used to
bind keys to the device or class of device. When loading keys
into a device, this identifier can be checked against information
obtained from the device to ensure that the correct device or
class of device is being used.
o <StartDate> (OPTIONAL), the start date of a device (such as the
one on a payment card, used when issue numbers are not printed on
cards). MUST be expressed in UTC form, with no time zone
component. Implementations SHOULD NOT rely on time resolution
finer than milliseconds and MUST NOT generate time instants that
specify leap seconds.
o <ExpiryDate> (OPTIONAL), the expiry date of a device (such as the
one on a payment card, used when issue numbers are not printed on
cards). MUST be expressed in UTC form, with no time zone
component. Implementations SHOULD NOT rely on time resolution
finer than milliseconds and MUST NOT generate time instants that
specify leap seconds.
o <Extensions> (OPTIONAL), is the extension point for this entity.
All extensions are grouped under this element and will be of type
pskc:ExtensionType, which contains an optional attribute
'defintion' that can have a URI pointing at the defintion of the
extension. In this way groups of extension can be bundled under a
subelement. For example:
<Extensions>
<MyExtension1 xmlns="http://ACME/MyExtension.xsd">blah</MyExtension1>
<YourExtension99 xmlns="http://ACME/YourExtension.xsd">blahblah
</YourExtension99>
</Extensions>
5.4. Key
The Key represents the key entity in the KeyContainer. The Key is
defined as follows:
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<xs:complexType name="KeyType">
<xs:sequence>
<xs:element name="Issuer" type="xs:string"
minOccurs="0"/>
<xs:element name="Usage" type="pskc:UsageType"
minOccurs="0"/>
<xs:element name="KeyProfileId" type="xs:string"
minOccurs="0"/>
<xs:element name="MasterKeyId" type="xs:string"
minOccurs="0"/>
<xs:element name="FriendlyName" type="xs:string"
minOccurs="0"/>
<xs:element name="Data" type="pskc:KeyDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="PINPolicy"
type="pskc:PINPolicyType" minOccurs="0"/>
<xs:element name="StartDate" type="xs:dateTime"
minOccurs="0"/>
<xs:element name="ExpiryDate" type="xs:dateTime"
minOccurs="0"/>
<xs:element name="UserId" type="xs:string"
minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="KeyId" type="xs:string"
use="required"/>
<xs:attribute name="KeyAlgorithm"
type="pskc:KeyAlgorithmType" use="optional"/>
<xs:attribute name="KeyProperties" type="xs:IDREF"
use="optional"/>
</xs:complexType>
The attributes of the Key entity have the following meanings:
o KeyId (MANDATORY), a unique and global identifier of the symmetric
key. The identifier is defined as a string of alphanumeric
characters. This identifier SHOULD be valid globally and outside
of the instance document of the container.
o KeyAlgorithm (MANDATORY), the unique URI of the type of algorithm
to use with the secret key, for profiles are described in
Section 6.3
o KeyProperties (OPTIONAL), the references to the unique id of the
KeyProperties whose value the instance of this key inherits. If
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this value is set implementation MUST lookup the Keyproperties
element referred to by this unique Id and this instance of key
will inherit all values from the KeyProperties. Values held in
the key instance MUST take precedence over values inherited from
KeyProperties."/>
The elements of the Key entity have the following meanings:
o <Issuer> (OPTIONAL), The key issuer name, this is normally the
name of the organization that issues the key to the end user of
the key. For example MyBank issuing hardware tokens to their
retail banking users 'MyBank' would be the issuer. The Issuer is
defined as a String.
o <Usage> (OPTIONAL), defines the intended usage of the key and
related metadata as defined in Section 5.4.2
o <KeyProfileId> (OPTIONAL), A unique identifier used between the
sending and receiving party of the container to establish a set of
key attribute values, common to one or more keys, that are not
transmitted witin the container but agreed between sending and
receiving party of the container out of band. This Id will then
represent the unique reference to a a set of attribute values.
For example a smart card application personalisation profile id
related to attributes present on a smart card application that
have influence when computing a response. An example would be
that a sending and receiving party agree on a set of values
related to the EMV MasterCard CAP [CAP] algorithm that application
on a card personalised with data for a specific batch of cards
such as:
IAF Internet authentication flag
CVN Cryptogram version number, for example (MCHIP2, MCHIP4,
VISA 13, VISA14)
AIP (Application Interchange Profile), 2 bytes
CVR The card verification result
IIPB
So sending and reciving party would agree thet KeyProfileId '1'
would represent a cetain set of values (e.g. IAF="80"). When
sending keys these values would not be transmitted as key
attributes but only referred to via the KeyProfileId element set
to the specific agreed profile (in this case '1'). WHen the
receiving party receives the keys it can then associate all
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relevant key attributes contained in the out of band agreed
profile with the imported keys. Often this methodology is used
between between the manufacturing and the validation service to
avoid transmission of mainly the same set of values. The
KeyProfileId is defined as a String.
o <MasterKeyId> (OPTIONAL), The unique reference to an external
master key when key derivation schemes are used and no specific
key is transported but only the reference to the master key used
to derive a specific key and some derivation data (e.g. the
PKCS#11 key label in an HSM).
o <FriendlyName> (OPTIONAL), The user friendly name that is assigned
to the secret key for easy reference. The FriendlyName is defined
as a String.
o <Data> (OPTIONAL), the element carrying the data related to the
key as defined in Section 5.4.1
o <PINPolicy> (OPTIONAL), the policy of the PIN relating to the
usage of this key as defined in Section 5.4.4
o <StartDate> (OPTIONAL), the start date of the key, it MUST not be
possible to use this key before this date. MUST be expressed in
UTC form, with no time zone component. Implementations SHOULD NOT
rely on time resolution finer than milliseconds and MUST NOT
generate time instants that specify leap seconds.
o <ExpiryDate> (OPTIONAL), the expiry date of the key, it MUST not
be possible to use this key after this date. MUST be expressed in
UTC form, with no time zone component. Implementations SHOULD NOT
rely on time resolution finer than milliseconds and MUST NOT
generate time instants that specify leap seconds.
o <UserId> (OPTIONAL), identifies the user account (e.g. username or
user id) to which the key is assigned. The value MUST be a string
representation of a Distinguished Name as defined in [RFC4514].
For example "UID=jsmith,DC=example,DC=net". In systems where
unique user Ids are used the string representation
'UID=[uniqueId]' SHOULD be used.
o <Extensions> (OPTIONAL), is the extension point for this entity.
All extensions are grouped under this element and will be of type
pskc:ExtensionType, which contains an optional attribute
'defintion' that can have a URI pointing at the defintion of the
extension. In this way groups of extension can be bundled under a
subelement. For example:
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<Extensions>
<MyExtension1 xmlns="http://ACME/MyExtension.xsd">blah</MyExtension1>
<YourExtension99 xmlns="http://ACME/YourExtension.xsd">blahblah
</YourExtension99>
</Extensions>
5.4.1. KeyData
Defines an extensible set of data elements relating to a key
including the key value itself (secret). After considerable
discussions in forums and at IETF the authors needed a mean to convey
data related to a key in an extensible form. A name-value pair
approach would be extensible for future new data fields but it lacks
support of typing. Hence the current apporach is to have within
KeyData a set of elements that have both typing and can be encrypted.
Regarding to the encryption, the requirements were that the data
elements could be simply encrypted. The XML encryption is adopted in
consideration of open standards and broad existing implementations.
In this document, a simplified profile of XML encryption is used that
only encrypts data value rather than XML elements. xenc:
EncryptedDataType is leveraged to carry encrypted data. This
simplified usage doesn't need to involve any XML canonicalization
among others.
All elements within <Data> hence obey a simple structure in that they
MUST have:
a choice between:
A <PlainValue> element that is typed to the specific type (e.g.
xs:integer)
An <EncryptedValue> element that is of type xenc:EncryptedDataType
where the value of the specific element is placed in case it is
encrypted
an optional <ValueMac> element that is populated with a MAC generated
from the unencrypted value in case the encryption algorithm does not
support integrity checks
For example the pskc:intDataType is defined as follows:
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<xs:complexType name="intDataType">
<xs:sequence>
<xs:choice>
<xs:element name="PlainValue"
type="xs:int"/>
<xs:element name="EncryptedValue"
type="xenc:EncryptedDataType"/>
</xs:choice>
<xs:element name="ValueMAC"
type="xs:base64Binary" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
The following typed base types have been defined within the current
schema of the PSKC spec with the naming convention <type>DataType
(e.g. intDataType) to be able to cater transmission of key data
elements:
pskc:intDataType - to carry data elements of type integer,
PlainValue sub element is of type xs:integer. When encrypted the
binary value MUST be 4 bytes unsigned integer in big endian (i.e.
network byte order) form
pskc:longDataType - to carry data elements of type long,
PlainValue sub element is of type xs:long. When encrypted the
binary value MUST be 8 bytes unsigned integer in big endian (i.e.
network byte order) form
pskc:binaryDataType - to carry data elements of type binary,
PlainValue sub element is of type xs:Base64Binary
pskc:stringDataType - to carry data elements of type string,
PlainValue sub element is of type xs:string. When encrypted the
binary value MUST UTF-8 encoded string in binary form
Therefore the KeyData element is defined as follows and contains sub
elements to convey the values required by algorithms considered
during the definition of this specification:
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<xs:complexType name="KeyDataType">
<xs:sequence>
<xs:element name="Secret" type="pskc:binaryDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="Counter" type="pskc:longDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="Time" type="pskc:intDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="TimeInterval" type="pskc:intDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="TimeDrift" type="pskc:intDataType"
minOccurs="0" maxOccurs="1"/>
<xs:any namespace="##other" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
The elements of the Data element have the following meanings:
o <Secret> (OPTIONAL), the value of the key itself in binary.
o <Counter> (OPTIONAL), the event counter for event based OTP
algorithms.
o <Time> (OPTIONAL), the time for time based OTP algorithms. (If
time interval is used, this element carries the number of time
intervals passed from a specific start point, normally algorithm
dependent)
o <TimeInterval> (OPTIONAL), the time interval value for time based
OTP algorithms.
o <TimeDrift> (OPTIONAL), the device clock drift value for time
based OTP algorithms. The value indicates number of seconds that
the device clock may drift each day.
o <xs:any ..> the extension point for carrying future elements.
Please note that all elements added MUST carry PlainValue and
EncryptedValue sub eleemnts as described above.
5.4.2. Usage
The Usage element defines the usage attribute(s) of the key entity.
Usage is defined as follows:
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<xs:complexType name="UsageType">
<xs:sequence>
<xs:element name="ChallengeFormat" minOccurs="0">
<xs:complexType>
<xs:attribute name="Format"
type="pskc:ValueFormatType"
use="required"/>
<xs:attribute name="Min"
type="xs:unsignedInt" use="required"/>
<xs:attribute name="Max"
type="xs:unsignedInt" use="required"/>
<xs:attribute name="CheckDigits"
type="xs:boolean" default="false"/>
</xs:complexType>
</xs:element>
<xs:element name="ResponseFormat">
<xs:complexType>
<xs:attribute name="Format"
type="pskc:ValueFormatType"
use="required"/>
<xs:attribute name="Length"
type="xs:unsignedInt" use="required"/>
<xs:attribute name="CheckDigits"
type="xs:boolean" default="false"/>
</xs:complexType>
</xs:element>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="OTP" type="xs:boolean"
default="false"/>
<xs:attribute name="CR" type="xs:boolean"
default="false"/>
<xs:attribute name="Integrity" type="xs:boolean"
default="false"/>
<xs:attribute name="Encrypt" type="xs:boolean"
default="false"/>
<xs:attribute name="Unlock" type="xs:boolean"
default="false"/>
<xs:anyAttribute namespace="##other"/>
</xs:complexType>
The attributes of the Usage element define the intended usage of the
key. This list of attributes is extensible for future needs. They
are a combination of one or more of the following (set to true):
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o OTP, the key will be used for OTP generation
o CR, the key will be used for Challenge/Response purposes
o Encrypt, the key will be used for data encryption purposes
o Integrity, the key will be used to generate a keyed message digest
for data integrity or authentication purposes.
o Unlock, the key will be used for an inverse challenge response in
the case a user has locked the device by entering a wrong PIN too
many times (for devices with PIN-input capability)
The <Extensions> (OPTIONAL) element, is the extension point for the
Usage entity. All extensions are grouped under this element and will
be of type pskc:ExtensionType, which contains an optional attribute
'defintion' that can have a URI pointing at the defintion of the
extension. In this way groups of extension can be bundled under a
subelement. For example:
<Extensions>
<MyExtension1 xmlns="http://ACME/MyExtension.xsd">blah</MyExtension1>
<YourExtension99 xmlns="http://ACME/YourExtension.xsd">blahblah
</YourExtension99>
</Extensions>
5.4.2.1. OTP and CR specific Usage elements
When the intended usage of a key usage is OTP and/or CR, the
following additional elements MUST be provided within the Usage
element to support the OTP and/or the response computation as
required by the underlying algorithm. These elements also allow
customizing or configuring the result of the computation (e.g.
format, length).
5.4.2.1.1. ChallengeFormat element (OPTIONAL)
The ChallengeFormat element defines the characteristics of the
challenge in a CR usage scenario. The Challenge element is defined
by the following attributes:
o Format (MANDATORY), defines the format of the challenge accepted
by the device and MUST be one of the values defined in
Section 5.4.3
o CheckDigit (OPTIONAL), defines if the device needs to check the
appended Luhn check digit, as defined in [LUHN], contained in a
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provided challenge. This is only valid if the Format attribute is
'DECIMAL'. Value MUST be:
TRUE device will check the appended Luhn check digit in a
provided challenge
FALSE device will not check appended Luhn check digit in
challenge
o Min (MANDATORY), defines the minimum size of the challenge
accepted by the device for CR mode. If the Format attribute is
'DECIMAL', 'HEXADECIMAL' or 'ALPHANUMERIC' this value indicates
the minimum number of digits/characters. If the Format attribute
is 'BASE64' or 'BINARY', this value indicates the minimum number
of bytes of the unencoded value. Value MUST be Unsigned integer.
o Max (MANDATORY), defines the maximum size of the challenge
accepted by the device for CR mode. If the Format attribute is
'DECIMAL', 'HEXADECIMAL' or 'ALPHANUMERIC' this value indicates
the maximum number of digits/characters. If the Format attribute
is 'BASE64' or 'BINARY', this value indicates the maximum number
of bytes of the unencoded value. Value MUST be Unsigned integer.
5.4.2.1.2. ResponseFormat element (MANDATORY)
The ResponseFormat element defines the characteristics of the result
of a computation. This defines the format of the OTP or of the
response to a challenge. For cases where the key is a PIN value,
this element contains the format of the PIN itself (e.g. DECIMAL,
length 4 for a 4 digit PIN). The Response attribute is defined by
the following attributes:
o Format (MANDATORY), defines the format of the response generated
by the device and MUST be one of the values defined in
Section 5.4.3
o CheckDigit (OPTIONAL), defines if the device needs to append a
Luhn check digit,as defined in [LUHN], to the response. This is
only valid if the Format attribute is 'DECIMAL'. Value MUST be:
TRUE device will append a Luhn check digit to the response.
FALSE device will not append a Luhn check digit to the
response.
o Length (MANDATORY), defines the length of the response generated
by the device. If the Format attribute is 'DECIMAL',
'HEXADECIMAL' or 'ALPHANUMERIC' this value indicates the number of
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digits/characters. If the Format attribute is 'BASE64' or
'BINARY', this value indicates the number of bytes of the
unencoded value. Value MUST be Unsigned integer.
5.4.3. ValueFormat
The ValueFormat element defines allowed formats for challenges or
responses in OTP algorithms.
ValueFormat is defined as follows:
<simpleType name="ValueFormat">
<restriction base="string">
<enumeration value="DECIMAL"/>
<enumeration value="HEXADECIMAL"/>
<enumeration value="ALPHANUMERIC"/>
<enumeration value="BASE64"/>
<enumeration value="BINARY"/>
</restriction>
</simpleType>
DECIMAL, Only numerical digits
HEXADECIMAL, Hexadecimal response
ALPHANUMERIC, All letters and numbers (case sensitive)
BASE64, Base 64 encoded
BINARY, Binary data, this is mainly used in case of connected
devices
5.4.4. PINPolicy
The PINPolicy element provides an extensible mean to define how the
usage of a specific key is protected by a PIN. The PIN itself can be
transmitted as a key using the container.
If the PINPolicy element is present in the Key element then the key
is protected with a PIN as defined within the PINPolicy element. The
PINPolicy element also has an extension point defined as xs:any to
allow future extensibility
PINPolicy is defined as follows:
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<xs:complexType name="PINPolicyType">
<xs:sequence>
<xs:element name="PINUsageMode" type="pskc:PINUsageModeType"/>
<xs:element name="MaxFailedAttempts" type="xs:unsignedInt"
minOccurs="0"/>
<xs:element name="MinLength"
type="xs:unsignedInt" minOccurs="0"/>
<xs:element name="MaxLength"
type="xs:unsignedInt" minOccurs="0"/>
<xs:element name="Format"
type="pskc:ValueFormatType" minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="PINKeyId" type="xs:string" use="optional"/>
</xs:complexType>
The attributes of PINPolicy have the following meaning
o PINKeyId (OPTIONAL), the unique key Id of the key held within this
container that contains the value of the PIN that protects the key
The elements of PINPolicy have the following meaning
o <PINUsageMode> (MANDATORY) , the way the PIN is used during the
usage of the key as defined in Section 5.4.4.1
o <MaxFailedAttempts> (OPTIONAL), the maximum number of times the
PIN can be entered wrongly before it MUST not be possible to use
the key anymore. If PinUsageMode is 'Local' the device MUST
enforce this value, otherwise it MUST be enforced by the
validation server.
o <MinLength> (OPTIONAL), the minimum lenght of a PIN that can be
set to protect this key. It MUST not be possible to set a PIN
shorter than this value. If the Format element is 'DECIMAL',
'HEXADECIMAL' or 'ALPHANUMERIC' this value indicates the number of
digits/characters. If the Format attribute is 'BASE64' or
'BINARY', this value indicates the number of bytes of the
unencoded value. If PinUsageMode is 'Local' the device MUST
enforce this value, otherwise it MUST be enforced by the
validation server.
o <MaxLength> (OPTIONAL), the maximum lenght 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 the Format element is 'DECIMAL',
'HEXADECIMAL' or 'ALPHANUMERIC' this value indicates the number of
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digits/characters. If the Format attribute is 'BASE64' or
'BINARY', this value indicates the number of bytes of the
unencoded value. If PinUsageMode is 'Local' the device MUST
enforce this value, otherwise it MUST be enforced by the
validation server.
o <Format> (OPTIONAL), defines the format of the PIN and MUST be one
of the values defined in Section 5.4.3. If PinUsageMode is
'Local' the device MUST enforce that the entered value is of this
format, otherwise it MUST be enforced by the validation server.
o <Extensions> (OPTIONAL) element, is the extension point for the
entity. All extensions are grouped under this element and will be
of type pskc:ExtensionType, which contains an optional attribute
'defintion' that can have a URI pointing at the defintion of the
extension. In this way groups of extension can be bundled under a
subelement. For example:
<Extensions>
<MyExtension1 xmlns="http://ACME/MyExtension.xsd">blah</MyExtension1>
<YourExtension99 xmlns="http://ACME/YourExtension.xsd">blahblah
</YourExtension99>
</Extensions>
5.4.4.1. PINUsageMode
The PINUsageMode element defines how the PIN is used with a specific
key. The PINUsageMode element also has an extension point defined as
xs:any to allow future extensibility
PINUsageMode is defined as follows:
<xs:complexType name="PINUsageModeType">
<xs:choice maxOccurs="unbounded">
<xs:element name="Local"/>
<xs:element name="Prepend"/>
<xs:element name="Append"/>
<xs:element name="Algorithmic"/>
<xs:any namespace="##other" processContents="lax"
minOccurs="0" maxOccurs="unbounded"/>
</xs:choice>
</xs:complexType>
The elements of PINPolicy have the following meaning
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o <Local>, the PIN is checked locally on the device before allowing
the key to be used in executing the algorithm
o <Prepend>, the PIN is prepended to the OTP or response hence it
MUST be checked by the validation server
o <Append>, the PIN is appended to the OTP or response hence it MUST
be checked by the validation server
o <Algorithmic>, the PIN is used as part of the algorithm
computation
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6. Usage and profile of algorithms for the portable symmetric key
container
This section details the use of the XML encryption and XML signature
elements to protect the keys transported in the container. It also
profiles the number of algorithms supported by XML encryption and XML
signature to a mandatory subset for interoperability.
When no algorithm is provided the values within the container are
unencrypted, implementations SHALL ensure the privacy of the key data
through other standard mechanisms e.g. transport level encryption.
6.1. Usage of EncryptionKey to protect keys in transit
The EncryptionKey element in the KeyContainer defines the key,
algorithm and parameters used to encrypt the Secret Key data
attributes in the Container. The standard schema [XMLENC] is adopted
in carry such information and an encrypted value. The encryption is
applied on each individual Secret Key data in the Container. The
encryption method MUST be the same for all Secret Key data in the
container.
The following sections define specifically the different supported
means to protect the keys:
6.1.1. Protecting keys using a pre-shared key via symmetric algorithms
When protecting the payload with pre-shared keys implementations
SHOULD set the name of the specific pre-shared key in the KeyName
element of the EncryptionKey of the KeyContainer. For example:
<KeyContainer Version="1.0"
xmlns="urn:ietf:params:xml:ns:keyprov:pskc:1.0"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
<EncryptionKey>
<ds:KeyName>PRE_SHARED_KEY</ds:KeyName>
</EncryptionKey>
....
The following is the list of symmetric key encryption algorithm and
possible parameters used to protect the Secret Key data in the
container. Systems implementing PSKC MUST support the MANDATORY
algorithms detailed below.
The encryption algorithm URI can be one of the following. This isn't
an exhausted list. The other future OPTIONAL encryption algorithms
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MAY be used.
o http://www.w3.org/2001/04/xmlenc#aes128-cbc - MANDATORY
o http://www.w3.org/2001/04/xmlenc#aes192-cbc - OPTIONAL
o http://www.w3.org/2001/04/xmlenc#aes256-cbc - OPTIONAL
o http://www.w3.org/2001/04/xmlenc#tripledes-cbc - OPTIONAL
o http://www.w3.org/2001/04/xmldsig-more#camellia128 - OPTIONAL
o http://www.w3.org/2001/04/xmldsig-more#camellia192 - OPTIONAL
o http://www.w3.org/2001/04/xmldsig-more#camellia256 - OPTIONAL
o http://www.w3.org/2001/04/xmlenc#kw-aes128 - OPTIONAL
o http://www.w3.org/2001/04/xmlenc#kw-aes192 - OPTIONAL
o http://www.w3.org/2001/04/xmlenc#kw-aes256 - OPTIONAL
o http://www.w3.org/2001/04/xmlenc#kw-tripledes - OPTIONAL
o http://www.w3.org/2001/04/xmldsig-more#kw-camellia128 - OPTIONAL
o http://www.w3.org/2001/04/xmldsig-more#kw-camellia192 - OPTIONAL
o http://www.w3.org/2001/04/xmldsig-more#kw-camellia256 - OPTIONAL
When algorithms without integrity checks are used (e.g.
http://www.w3.org/2001/04/xmlenc#aes128-cbc) a keyed MAC value using
the same key as the key encryption key SHOULD be placed in the
ValueMAC element of the Data element. In this case the MAC algorithm
type MUST be set in the MACAlgorithm element in the key container
entity as defined in Section 5.1. Implementations of PSKC MUST
support the MANDATORY MAC algorithms detailed below. The
MACAlgorithm URI can be one of the following:
o http://www.w3.org/2000/09/xmldsig#hmac-sha1 - MANDATORY
o http://www.w3.org/2001/04/xmldsig-more#hmac-sha256 - OPTIONAL
o http://www.w3.org/2001/04/xmldsig-more#hmac-sha384 - OPTIONAL
o http://www.w3.org/2001/04/xmldsig-more#hmac-sha512 - OPTIONAL
For example:
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<KeyContainer Version="1.0"
xmlns="urn:ietf:params:xml:ns:keyprov:pskc:1.0"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
<EncryptionKey>
<ds:KeyName>PRE_SHARED_KEY</ds:KeyName>
</EncryptionKey>
<MACAlgorithm>http://www.w3.org/2000/09/xmldsig#hmac-sha1
</MACAlgorithm>
.....
6.1.2. Protecting keys using passphrase based key encryption keys
To be able to support passphrase based key encryption keys as defined
in PKCS#5 the following XML representation of the PBE relates
parameters have been introduced in the schema. Although the approach
is extensible implementations of PSKC MUST support the PKCS#5
recommended PBKDF2 and PBES2. Differing from the PKCS#5 XML schema
definition, the PBKDF2 and PBES2 are specified in two separate
elements in a <KeyContainer>. Considering that the same key
encryption key is used to encrypt all <Key> data in a container, the
PBKDF2 is specified in a newly defined subelement <DerivedKey> of the
<EncryptionKey>. The PBES2 is specified by the algorithm attribute
of EncryptionMethod in the encrypted data elements with the URI
http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbes2.
In the following, we introduce a newly defined type <DerivedKeyType>.
It is used to carry passphrase based key derivation information. An
instance of the type MUST be included in the EncryptionKey to
indicate the passphrase identifier and key derivation. This type is
defined as follows.
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<xs:complexType name="DerivedKeyType">
<xs:sequence>
<xs:element name="CarriedKeyName" type="xs:string"
minOccurs="0"/>
<xs:element name="KeyDerivationMethod"
type="pskc:KeyDerivationMethodType" minOccurs="0"/>
<xs:element ref="xenc:ReferenceList" minOccurs="0"/>
</xs:sequence>
<xs:attribute ref="xml:id" use="optional"/>
<xs:attribute name="Type" type="xs:anyURI" use="optional"/>
</xs:complexType>
<xs:complexType name="KeyDerivationMethodType">
<xs:sequence>
<xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="Algorithm" type="xs:anyURI"
use="required"/>
</xs:complexType>
<xs:element name="DerivedKey" type="pskc:DerivedKeyType"/>
The attributes of the DerivedKey have the following meanings:
o xml:id (OPTIONAL), the unique ID for this key
o Type (OPTIONAL), This attribute was included for conformance with
xml encryption, it is an optional attribute identifying type
information about the plaintext form of the encrypted content.
Please see [XMLENC] section 3.1 Type for more details.
The elements of the DerivedKey have the following meanings:
o <CarriedKeyName> (OPTIONAL): friendly name of the key
o <KeyDerivationMethod>: define how key encryption key is derived.
Its algorithm attribute is used to indicate the key derivation
method. When PBKDF2 is used, the URI
http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbkdf2 MUST
be used. The extensible content <xs:any> of the element can
include any other informations associated with the given
algorithm. When PBKDF2 is used, it MUST include a subelement
<pkcs-5:PBKDF2-params> to indicate the PBKDF2 parameters such as
salt and iteration count values..
o <ReferenceList> (OPTIONAL): a list of IDs of the elements that
have been encrypted by this key
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When PBES2 is used for encryption, its URL
http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbes2 MUST be
specified as the algorithm attribute of <xenc:EncryptionMethod>, and
its related parameters such as underlying encryption scheme and
associated parameters such as initialization vector MUST be included
set in a subelement <pskc:EncryptionScheme> included in <xenc:
EncryptionMethod>. The EncryptionScheme is defined as follows.
<xs:element name="EncryptionScheme" type="xenc:EncryptionMethodType"/>
When PKCS#5 password based encryption is used, the EncryptionKey and
EncryptionMethod MUST be used in exactly the form as shown below.
<?xml version="1.0" encoding="UTF-8"?>
<KeyContainer
xmlns="urn:ietf:params:xml:ns:keyprov:pskc:1.0"
xmlns:pkcs-5=
"http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5v2-0#"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"
Version="1.0">
<pskc:EncryptionKey>
<pskc:DerivedKey>
<pskc:CarriedKeyName>Passphrase1</pskc:CarriedKeyName>
<pskc:KeyDerivationMethod
Algorithm=
"http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbkdf2">
<pkcs-5:PBKDF2-params>
<Salt>
<Specified>Df3dRAhjGh8=</Specified>
</Salt>
<IterationCount>2000</IterationCount>
<KeyLength>16</KeyLength>
<PRF/>
</pkcs-5:PBKDF2-params>
</pskc:KeyDerivationMethod>
<xenc:ReferenceList>
<xenc:DataReference URI="#ED"/>
</xenc:ReferenceList>
</pskc:DerivedKey>
</pskc:EncryptionKey>
....
<pskc:Device>
...
<pskc:Key KeyAlgorithm="http://www.ietf.org/keyprov/pskc#hotp"
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<pskc:Secret>
<pskc:EncryptedValue Id="ED">
<xenc:EncryptionMethod Algorithm=
"http://www.rsasecurity.com/rsalabs/pkcs/schemas/
pkcs-5#pbes2">
<pskc:EncryptionScheme Algorithm=
"http://www.w3.org/2001/04/xmlenc#aes128-cbc">
</pskc:EncryptionScheme>
</xenc:EncryptionMethod>
<xenc:CipherData>
<xenc:CipherValue>rf4dx3rvEPO0vKtKL14NbeVu8nk=
</xenc:CipherValue>
</xenc:CipherData>
</pskc:EncryptedValue>
</pskc:Secret>
</pskc:Key>
</pskc:Device>
6.2. Protecting keys using asymmetric algorithms
The following is the list of asymmetric key encryption algorithm and
possible parameters used to protect the Secret Key data in the
container. Systems implementing PSKC MUST support the MANDATORY
algorithms detailed below. The encryption algorithm URI can be one
of the following.
o http://www.w3.org/2001/04/xmlenc#rsa-1_5 - MANDATORY
o http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p - OPTIONAL
For example:
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<?xml version="1.0" encoding="UTF-8"?>
<pskc:KeyContainer Version="1.0"
xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc:1.0"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
<pskc:EncryptionKey>
<ds:X509Data>
<ds:X509Certificate>miib</ds:X509Certificate>
</ds:X509Data>
</pskc:EncryptionKey>
<pskc:Device>
<pskc:DeviceInfo>
<pskc:Manufacturer>Manufacturer</pskc:Manufacturer>
<pskc:SerialNo>0755225266</pskc:SerialNo>
</pskc:DeviceInfo>
<pskc:Key KeyAlgorithm=
"http://www.ietf.org/keyprov/pskc#hotp"
KeyId="0755225266">
<pskc:Issuer>AnIssuer</pskc:Issuer>
<pskc:Usage OTP="true">
<pskc:ResponseFormat Length="8"
Format="DECIMAL"/>
</pskc:Usage>
<pskc:Data>
<pskc:Secret>
<pskc:EncryptedValue Id="ED">
<xenc:EncryptionMethod Algorithm=
"http://www.w3.org/2001/04/xmlenc#rsa_1_5"/>
<xenc:CipherData>
<xenc:CipherValue>rf4dx3rvEPO0vKtKL14NbeVu8nk=
</xenc:CipherValue>
</xenc:CipherData>
</pskc:EncryptedValue>
</pskc:Secret>
<pskc:Counter>
<PlainValue>0</PlainValue>
</pskc:Counter>
</pskc:Data>
</pskc:Key>
</pskc:Device>
</pskc:KeyContainer>
6.3. Profile of Key Algorithm
This section profiles the type(s) of algorithm of that can be used by
the key(s) transported in the container. The following algorithm
URIs are among the default support list.
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o http://www.w3.org/2001/04/xmlenc#tripledes-cbc
o http://www.w3.org/2001/04/xmlenc#aes128-cbc
o http://www.w3.org/2001/04/xmlenc#aes192-cbc
o http://www.w3.org/2001/04/xmlenc#aes256-cbc
o http://www.ietf.org/keyprov/pskc#hotp
o http://www.ietf.org/keyprov/pskc#pin
6.3.1. OTP Key Algorithm Identifiers
OTP key algorithm URIs have not been defined in a commonly available
standard specification. This document requests from IANA the
creation of a registry (see Section 8.4) and defines URIs for the
standard OTP algorithms in Section 8.4.4.
6.3.2. PIN key value compare algorithm identifier
PIN key algorithm URIs have not been defined in a commonly available
standard specification. This document defines the following URIs for
a straight value comparison of the transported secret key data as
when required to compare a PIN.
Identifier: http://www.ietf.org/keyprov/pskc#pin
Note that the actual URL will be finalized once a URL for this
document is determined.
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7. Formal Syntax
The following syntax specification uses the widely adopted XML schema
format as defined by a W3C recommendation
(http://www.w3.org/TR/xmlschema-0/). It is a complete syntax
definition in the XML Schema Definition format (XSD)
All implementations of this standard must comply with the schema
below.
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc:1.0"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"
targetNamespace="urn:ietf:params:xml:ns:keyprov:pskc:1.0"
elementFormDefault="qualified" attributeFormDefault="unqualified"
version="1.0">
<xs:import namespace="http://www.w3.org/2000/09/xmldsig#"
schemaLocation=
"http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/
xmldsig-core-schema.xsd"/>
<xs:import namespace="http://www.w3.org/2001/04/xmlenc#"
schemaLocation="http://www.w3.org/TR/2002/
REC-xmlenc-core-20021210/xenc-schema.xsd"/>
<xs:import namespace="http://www.w3.org/XML/1998/namespace"/>
<xs:complexType name="KeyContainerType">
<xs:sequence>
<xs:element name="EncryptionKey" type="ds:KeyInfoType"
minOccurs="0"/>
<xs:element name="MACAlgorithm" type="pskc:KeyAlgorithmType"
minOccurs="0"/>
<xs:element name="KeyProperties"
type="pskc:KeyPropertiesType" minOccurs="0"
maxOccurs="unbounded"/>
<xs:element name="Device" type="pskc:DeviceType"
minOccurs="1" maxOccurs="unbounded"/>
<xs:element name="Signature" type="ds:SignatureType"
minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="Version" type="pskc:VersionType"
use="required"/>
<xs:attribute ref="xml:id" use="optional"/>
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</xs:complexType>
<xs:simpleType name="VersionType" final="restriction">
<xs:restriction base="xs:string">
<xs:pattern value="\d{1,2}\.\d{1,3}"/>
</xs:restriction>
</xs:simpleType>
<xs:complexType name="KeyPropertiesType">
<xs:sequence>
<xs:element name="Issuer"
type="xs:string" minOccurs="0"/>
<xs:element name="Usage"
type="pskc:UsageType" minOccurs="0"/>
<xs:element name="KeyProfileId"
type="xs:string" minOccurs="0"/>
<xs:element name="MasterKeyId"
type="xs:string" minOccurs="0"/>
<xs:element name="Data" type="pskc:KeyDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="PINPolicy"
type="pskc:PINPolicyType" minOccurs="0"/>
<xs:element name="StartDate"
type="xs:dateTime" minOccurs="0"/>
<xs:element name="ExpiryDate"
type="xs:dateTime" minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute ref="xml:id" use="required"/>
<xs:attribute name="KeyAlgorithm"
type="pskc:KeyAlgorithmType"
use="required"/>
</xs:complexType>
<xs:complexType name="KeyType">
<xs:sequence>
<xs:element name="Issuer"
type="xs:string" minOccurs="0"/>
<xs:element name="Usage"
type="pskc:UsageType"/>
<xs:element name="KeyProfileId"
type="xs:string" minOccurs="0"/>
<xs:element name="MasterKeyId"
type="xs:string" minOccurs="0"/>
<xs:element name="FriendlyName"
type="xs:string" minOccurs="0"/>
<xs:element name="Data" type="pskc:KeyDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="PINPolicy"
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type="pskc:PINPolicyType" minOccurs="0"/>
<xs:element name="StartDate"
type="xs:dateTime" minOccurs="0"/>
<xs:element name="ExpiryDate"
type="xs:dateTime" minOccurs="0"/>
<xs:element name="UserId" type="xs:string"
minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="KeyId"
type="xs:string" use="required"/>
<xs:attribute name="KeyAlgorithm"
type="pskc:KeyAlgorithmType"
use="optional"/>
<xs:attribute name="KeyProperties"
type="xs:IDREF" use="optional"/>
</xs:complexType>
<xs:complexType name="KeyDataType">
<xs:sequence>
<xs:element name="Secret"
type="pskc:binaryDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="Counter"
type="pskc:longDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="Time"
type="pskc:intDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="TimeInterval"
type="pskc:intDataType"
minOccurs="0" maxOccurs="1"/>
<xs:element name="TimeDrift"
type="pskc:intDataType"
minOccurs="0" maxOccurs="1"/>
<xs:any namespace="##other"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="binaryDataType">
<xs:sequence>
<xs:choice>
<xs:element name="PlainValue"
type="xs:base64Binary"/>
<xs:element name="EncryptedValue"
type="xenc:EncryptedDataType"/>
</xs:choice>
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<xs:element name="ValueMAC"
type="xs:base64Binary" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="intDataType">
<xs:sequence>
<xs:choice>
<xs:element name="PlainValue"
type="xs:int"/>
<xs:element name="EncryptedValue"
type="xenc:EncryptedDataType"/>
</xs:choice>
<xs:element name="ValueMAC"
type="xs:base64Binary" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="stringDataType">
<xs:sequence>
<xs:choice>
<xs:element name="PlainValue"
type="xs:string"/>
<xs:element name="EncryptedValue"
type="xenc:EncryptedDataType"/>
</xs:choice>
<xs:element name="ValueMAC"
type="xs:base64Binary" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="longDataType">
<xs:sequence>
<xs:choice>
<xs:element name="PlainValue"
type="xs:long"/>
<xs:element name="EncryptedValue"
type="xenc:EncryptedDataType"/>
</xs:choice>
<xs:element name="ValueMAC"
type="xs:base64Binary" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="DerivedKeyType">
<xs:sequence>
<xs:element name="KeyDerivationMethod"
type="pskc:KeyDerivationMethodType" minOccurs="0"/>
<xs:element ref="xenc:ReferenceList" minOccurs="0"/>
<xs:element name="CarriedKeyName" type="xs:string"
minOccurs="0"/>
</xs:sequence>
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<xs:attribute ref="xml:id" use="optional"/>
<xs:attribute name="Type" type="xs:anyURI" use="optional"/>
</xs:complexType>
<xs:complexType name="KeyDerivationMethodType">
<xs:sequence>
<xs:any namespace="##other" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="Algorithm" type="xs:anyURI"
use="required"/>
</xs:complexType>
<xs:complexType name="PINPolicyType">
<xs:sequence>
<xs:element name="PINUsageMode"
type="pskc:PINUsageModeType"/>
<xs:element name="MaxFailedAttempts" type="xs:unsignedInt"
minOccurs="0"/>
<xs:element name="MinLength"
type="xs:unsignedInt" minOccurs="0"/>
<xs:element name="MaxLength"
type="xs:unsignedInt" minOccurs="0"/>
<xs:element name="Format"
type="pskc:ValueFormatType" minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="PINKeyId" type="xs:string"
use="optional"/>
</xs:complexType>
<xs:complexType name="PINUsageModeType">
<xs:choice maxOccurs="unbounded">
<xs:element name="Local"/>
<xs:element name="Prepend"/>
<xs:element name="Append"/>
<xs:element name="Algorithmic"/>
<xs:any namespace="##other"
processContents="lax" minOccurs="0"
maxOccurs="unbounded"/>
</xs:choice>
</xs:complexType>
<xs:complexType name="DeviceInfoType">
<xs:sequence>
<xs:element name="Manufacturer" type="xs:string"/>
<xs:element name="SerialNo" type="xs:string"/>
<xs:element name="Model" type="xs:string"
minOccurs="0"/>
<xs:element name="IssueNo" type="xs:string"
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minOccurs="0"/>
<xs:element name="DeviceBinding" type="xs:string"
minOccurs="0"/>
<xs:element name="StartDate" type="xs:dateTime"
minOccurs="0"/>
<xs:element name="ExpiryDate" type="xs:dateTime"
minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="DeviceType">
<xs:sequence>
<xs:element name="DeviceInfo" type="pskc:DeviceInfoType"
minOccurs="0"/>
<xs:element name="Key" type="pskc:KeyType"
maxOccurs="unbounded"/>
<xs:element name="User" type="xs:string"
minOccurs="0"/>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="UsageType">
<xs:sequence>
<xs:element name="ChallengeFormat" minOccurs="0">
<xs:complexType>
<xs:attribute name="Format"
type="pskc:ValueFormatType" use="required"/>
<xs:attribute name="Min" type="xs:unsignedInt"
use="required"/>
<xs:attribute name="Max" type="xs:unsignedInt"
use="required"/>
<xs:attribute name="CheckDigits" type="xs:boolean"
default="false"/>
</xs:complexType>
</xs:element>
<xs:element name="ResponseFormat">
<xs:complexType>
<xs:attribute name="Format"
type="pskc:ValueFormatType" use="required"/>
<xs:attribute name="Length" type="xs:unsignedInt"
use="required"/>
<xs:attribute name="CheckDigits" type="xs:boolean"
default="false"/>
</xs:complexType>
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</xs:element>
<xs:element name="Extensions"
type="pskc:ExtensionsType" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="OTP" type="xs:boolean" default="false"/>
<xs:attribute name="CR" type="xs:boolean" default="false"/>
<xs:attribute name="Integrity" type="xs:boolean"
default="false"/>
<xs:attribute name="Encrypt" type="xs:boolean"
default="false"/>
<xs:attribute name="Unlock" type="xs:boolean"
default="false"/>
<xs:anyAttribute namespace="##other"/>
</xs:complexType>
<xs:complexType name="ExtensionsType">
<xs:sequence>
<xs:any namespace="##other" processContents="lax"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="definition" type="xs:anyURI"
use="optional"/>
</xs:complexType>
<xs:simpleType name="KeyAlgorithmType">
<xs:restriction base="xs:anyURI"/>
</xs:simpleType>
<xs:simpleType name="ValueFormatType">
<xs:restriction base="xs:string">
<xs:enumeration value="DECIMAL"/>
<xs:enumeration value="HEXADECIMAL"/>
<xs:enumeration value="ALPHANUMERIC"/>
<xs:enumeration value="BASE64"/>
<xs:enumeration value="BINARY"/>
</xs:restriction>
</xs:simpleType>
<xs:element name="DerivedKey" type="pskc:DerivedKeyType"/>
<xs:element name="EncryptionScheme"
type="xenc:EncryptionMethodType"/>
<xs:element name="KeyContainer" type="pskc:KeyContainerType"/>
</xs:schema>
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8. IANA Considerations
8.1. Content-type registration for 'application/pskc+xml'
This specification requests the registration of a new MIME type
according to the procedures of RFC 4288 [RFC4288] and guidelines in
RFC 3023 [RFC3023].
MIME media type name: application
MIME subtype name: pskc+xml
Mandatory parameters: none
Optional parameters: charset
Indicates the character encoding of enclosed XML.
Encoding considerations: Uses XML, which can employ 8-bit
characters, depending on the character encoding used. See RFC
3023 [RFC3023], Section 3.2.
Security considerations: This content type is designed to carry PSKC
protocol payloads.
Interoperability considerations: None
Published specification: RFCXXXX [NOTE TO IANA/RFC-EDITOR: Please
replace XXXX with the RFC number of this specification.]
Applications which use this media type: This MIME type is being used
as a symmetric key container format for transport and provisioning
of symmetric keys (One Time Password (OTP) shared secrets or
symmetric cryptographic keys) to different types of strong
authentication devices. As such, it is used for key provisioning
systems.
Additional information:
Magic Number: None
File Extension: .pskcxml
Macintosh file type code: 'TEXT'
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Personal and email address for further information: Philip Hoyer,
Philip.Hoyer@actividentity.com
Intended usage: LIMITED USE
Author: This specification is a work item of the IETF KEYPROV
working group, with mailing list address <keyprov@ietf.org>.
Change controller: The IESG <iesg@ietf.org>
8.2. XML Schema Registration
This section registers an XML schema as per the guidelines in
[RFC3688].
URI: urn:ietf:params:xml:ns:keyprov:pskc:1.0
Registrant Contact: IETF KEYPROV Working Group, Philip Hoyer
(Philip.Hoyer@actividentity.com).
XML Schema: The XML schema to be registered is contained in
Section 7. Its first line is
<?xml version="1.0" encoding="UTF-8"?>
and its last line is
</xs:schema>
8.3. URN Sub-Namespace Registration for
urn:ietf:params:xml:ns:keyprov:pskc:1.0
This section registers a new XML namespace,
"urn:ietf:params:xml:ns:keyprov:pskc:1.0", per the guidelines in
[RFC3688].
URI: urn:ietf:params:xml:ns:keyprov:pskc:1.0
Registrant Contact: IETF KEYPROV Working Group, Philip Hoyer
(Philip.Hoyer@actividentity.com).
XML:
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BEGIN
<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
"http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type"
content="text/html;charset=iso-8859-1"/>
<title>PSKC Namespace</title>
</head>
<body>
<h1>Namespace for PSKC</h1>
<h2>urn:ietf:params:xml:ns:keyprov:pskc:1.0</h2>
<p>See <a href="[URL of published RFC]">RFCXXXX
[NOTE TO IANA/RFC-EDITOR:
Please replace XXXX with the RFC number of this
specification.]</a>.</p>
</body>
</html>
END
8.4. Symmetric Key Algorithm Identifier Registry
This specification requests the creation of a new IANA registry for
symmetric key cryptographic algorithm identifiers in accordance with
the principles set out in RFC 5226 [RFC5226]as follows:
8.4.1. Applicability
The use of URIs as algorithm identifiers provides an effectively
unlimited namespace. While this eliminates the possibility of
namespace exhaustion it creates a new concern, that divergent
identifiers will be employed for the same purpose in different
contexts.
The key algorithm registry is intended to provide a means of
specifying the canonical identifier to be used for a given algorithm.
If an algorithm has an identifier specified in the registry an
application that is conformant to a protocol specification that
specifies use of that registry to define identifiers SHOULD always
use that particular form of the identifier when originating data. A
conformant application MAY accept other identifiers in data that is
received.
For the sake of expediency, the initial registry only defines
algorithm classes for symmetric algorithms plus cryptographic message
digest functions (one-way hash). While the same principles may be
extended to asymmetric algorithms, doing so would require much
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greater consideration of issues such as key length and treatment of
parameters, particularly where elliptic curve cryptography algorithms
are concerned.
As part of this registry the IANA will maintain the following
information:
Common Name The name by which the algorithm is generally referred.
Class The type of algorithm, encryption, Message Authentication Code
(MAC), One Time Password (OTP), Digest, etc.
Canonical URI The canonical URI to be used to identify the
algorithm.
Algorithm Definition A reference to the document in which the
algorithm described by the identifier is defined.
Identifier Definition A reference to the document in which the use
of the identifier to refer to the algorithm is described. This
would ideally be the document in which the algorithm is defined.
In the case where the registrant does not request a particular
URI, the IANA will assign it a Uniform Resource Name (URN) that
follows RFC 3553 [RFC3553].
Note that where a single algorithm has different forms distinguished
by parameters such as key length, the algorithm class and each
combination of algorithm parameters may be considered a distinct
algorithm for the purpose of assigning identifiers.
8.4.2. Registerable Algorithms
8.4.2.1. Assigned URIs
If the registrant wishes to have a URI assigned, then a URN of the
form
urn:ietf:params:xml:<class>:<id>
will be assigned where <class> is the type of the algorithm being
identified (see below). <id> is a unique id specified by the party
making the request and will normally be either the common name of the
algorithm or an abbreviation thereof.
NOTE: in order for a URN of this type to be assigned, the item being
registered MUST have been through the IETF consensus process.
Basically, this means that it must be documented in a RFC.
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NOTE: Expert Review is sufficient in cases where the request does not
require a URN assignment in the IETF namespace. IETF consensus is
not required.
8.4.2.2. Assigned Classes
Each algorithm MUST belong to an assigned algorithm class. In the
case that additional classes are required these are to be specified
by IETF Consensus action.
The initial assigned classes are:
Digest A cryptographic Digest algorithm.
MAC A Message Authentication Code algorithm.
Symmetric A symmetric encryption algorithm.
OTP A one time password (OTP) algorithm.
8.4.3. Registration Procedures
8.4.3.1. Review
Algorithm identifier registrations are to be subject to Expert Review
as per RFC 5226 [RFC5226].
The need for supporting documentation for the registration depends on
the nature of the request. In the case of a cryptographic algorithm
that is being described for publication as an RFC, the request for a
URI allocation would normally appear within the RFC itself. In the
case of a cryptographic algorithm that is fully and comprehensively
defined in another form, it would not be necessary to duplicate the
information for the sake of issuing the information in the RFC
series. In other cases an RFC may be required in order to ensure
that certain algorithm parameters are sufficiently and unambiguously
defined.
The scope of such expert review is to be strictly limited to
identifying possible ambiguity and/or duplication of existing
identifiers. The expert review MUST NOT consider the cryptographic
properties, intellectual property considerations or any other factor
not related to the use of the identifier.
In reviewing a request, the expert should consider whether other URI
identifiers are already defined for a given algorithm. In such cases
it is the duty of the expert to bring the potential duplication to
the notice of the proposers of the registration and the Security Area
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Directors. If the proposers are not willing to accept registration
of the existing identifier the IETF Consensus policy is to apply.
In reviewing a request, the expert should consider whether the
algorithm is sufficiently defined to allow successful interoperation.
In particular the expert should consider whether issues such as key
sizes and byte order are sufficiently defined to allow for
interoperation.
While the definition requirement MAY be satisfed by a comprehensive
specification of the algorithm, disclosure of the algorithm is not
mandatory.
8.4.3.2. Canonical URI
Until the IANA requests or implements an automated process for the
registration of these elements, any specifications must make that
request part of the IANA considerations section of their respective
documents. That request must be in the form of the following
template:
Common Name The name by which the algorithm is generally referred.
Class The type of algorithm, encryption, Message Authentication Code
(MAC), One Time Password (OTP), Digest, etc. As specified by a
defined algorithm class.
URI The canonical URI to be used to identify the algorithm.
Algorithm Definition A reference to the document in which the
algorithm described by the identifier is defined.
Identifier Definition A reference to the document in which the use
of the identifier to refer to the algorithm is described. This
would ideally be the document in which the algorithm is defined.
Registrant Contact A reference to the document in which the use of
the identifier to refer to the algorithm is described. This would
ideally be the document in which the algorithm is defined.
8.4.3.3. Alias URI
In the case that multiple identifiers have been assigned to the same
identifiers, additional identifiers MAY be registered as aliases. An
entry for an alias contains all the entries for a canonical URI with
the addition of a reference to the canonical URI to be used:
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Alias for URI The canonical URI that identifies the algorithm. The
URI referenced MUST be a canonical URI.
In the case of dispute as to which URI is to be considered canonical
the matter is to be settled by IESG action.
8.4.4. Initial Values
The following initial values are defined. Note that these values are
limited to identifiers that are required by KEYPROV but not specified
elsewhere:
8.4.4.1. HOTP
Common Name: HOTP
Class: OTP
URI: http://www.ietf.org/keyprov/pskc#hotp
Algorithm Definition: http://www.ietf.org/rfc/rfc4226.txt
Identifier Definition: (this RFC)
Registrant Contact: IESG
Profile of XML attributes and subelements of the <Key> entity:
For a <Key> of this algorithm, the <Usage> subelements MUST be
present. The "OTP" attribute of the <Usage> MUST be set "true"
and it MUST be the only attribute set. The element
<ResponseFormat> of the <Usage> MUST be used to indicate the OTP
length and the value format.
For the <Data> elements of a <Key> of this algorithm, the
following subelements MUST be present in either the <Key> element
itself or an commonly shared <KeyProperties> element.
* Counter
The following additional constraints apply:
- The value of the <Secret> element MUST contain key material
with a lengthy of at least 16 octets (128 bits) if it is
present.
- The <ResponseFormat> element MUST have the 'Format' attribute
set to "DECIMAL", and the 'Length' attribute MUST be between 6
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and 9.
- The <PINPolicy> element MAY be present but the <Format> child
element of the <PINPolicy> element cannot be set to
"Algorithmic".
An example of a <Key> of this algorithm is as follows.
<?xml version="1.0" encoding="UTF-8"?>
<KeyContainer Version="1.0"
xmlns="urn:ietf:params:xml:ns:keyprov:pskc:1.0">
<Device>
<DeviceInfo>
<Manufacturer>TokenVendorAcme</Manufacturer>
<SerialNo>987654321</SerialNo>
</DeviceInfo>
<Key KeyAlgorithm="http://www.ietf.org/keyprov/pskc#hotp"
KeyId="987654321">
<Issuer>Issuer</Issuer>
<Usage OTP="true">
<ResponseFormat Length="8" Format="DECIMAL"/>
</Usage>
<Data>
<Secret>
<PlainValue>MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=</PlainValue>
</Secret>
<Counter>
<PlainValue>0</PlainValue>
</Counter>
</Data>
</Key>
</Device>
</KeyContainer>
8.4.4.2. OCRA (OATH Chellenge Response Algorithm)
Common Name: OCRA
Class: OTP
URI: http://www.ietf.org/keyprov/pskc#OCRA-1:(ocra_suite_parameters)
- e.g.
http://www.ietf.org/keyprov/pskc#OCRA-1:HOTP-SHA512-8:C-QN08
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Algorithm Definition: http://www.ietf.org/internet-drafts/
draft-mraihi-mutual-oath-hotp-variants-07.txt
Identifier Definition (this RFC)
Registrant Contact: IESG
Profile of XML attributes and subelements of the <Key> entity:
For a <Key> of this algorithm, the <Usage> subelements MUST be
present. The "CR" attribute of the <Usage> MUST be set "true" and
it MUST be the only attribute set. The element <ChallengeFormat>
and <ResponseFormat> of the <Usage> MUST be present.
For the <Data> elements of a <Key> of this algorithm, the
following subelements MUST be present in either the <Key> element
itself or an commonly shared <KeyProperties> element.
* Counter
* Time
If the element <Time> is present, the following elements MUST be
also present.
* TimeInterval
The following additional constraints apply:
- The value of the <Secret> element MUST contain key material
with a lengthy of at least 16 octets (128 bits) if it is
present.
- The <ResponseFormat> element MUST have the 'Format' attribute
set to "DECIMAL", and the 'Length' attribute MUST be between 6
and 9.
- The <PINPolicy> element MAY be present but the <Format> child
element of the <PINPolicy> element cannot be set to
"Algorithmic".
An example of a <Key> of this algorithm is as follows.
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<?xml version="1.0" encoding="UTF-8"?>
<KeyContainer Version="1.0"
xmlns="urn:ietf:params:xml:ns:keyprov:pskc:1.0">
<Device>
<DeviceInfo>
<Manufacturer>TokenVendorAcme</Manufacturer>
<SerialNo>987654322</SerialNo>
</DeviceInfo>
<Key KeyId="12345678"
KeyAlgorithm="http://www.ietf.org/keyprov/
pskc#OCRA-1:HOTP-SHA512-8:C-QN08">
<Issuer>Issuer</Issuer>
<Usage CR="true">
<ChallengeFormat Min="8" Max="8" Format="DECIMAL"/>
<ResponseFormat Length="8" Format="DECIMAL"/>
</Usage>
<Data>
<Secret>
<PlainValue>MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=</PlainValue>
</Secret>
<Counter>
<PlainValue>0</PlainValue>
</Counter>
</Data>
</Key>
</Device>
</KeyContainer>
8.4.4.3. TOTP (OATH Time based OTP)
Common Name: TOTP
Class: OTP
URI: http://www.ietf.org/keyprov/pskc#totp
Algorithm Definition: http://www.ietf.org/internet-drafts/
draft-mraihi-totp-timebased-00.txt
Identifier Definition (this RFC)
Registrant Contact: IESG
Profile of XML attributes and subelements of the <Key> entity:
For a <Key> of this algorithm, the <Usage> subelements MUST be
present. The "OTP" attribute of the <Usage> MUST be set "true"
and it MUST be the only attribute set. The element
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<ResponseFormat>
