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:
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 (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 (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 (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 (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 (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 (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:
blahblahblah
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:
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:
The elements of the Device have the following meanings:
o (OPTIONAL), a set of elements containing information
about the device, whose values uniquely identify the device,
defined in Section 5.3.1
o (MANDATORY), represents the key entity as defined in
Section 5.4
o (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 (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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blahblahblah
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:
The elements of DeviceInfo have the following meanings:
o (MANDATORY), the manufacturer of the device.
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o (MANDATORY), the serial number of the device or the PAN
(primary account number) in case of payment smart cards.
o (OPTIONAL), the model of the device (e.g. one-button-HOTP-
token-V1)
o (OPTIONAL), the issue number in case of smart cards with
the same PAN, equivalent to a PSN (PAN Sequence Number).
o (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 (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 (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 (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:
blahblahblah
5.4. Key
The Key represents the key entity in the KeyContainer. The Key is
defined as follows:
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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 (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 (OPTIONAL), defines the intended usage of the key and
related metadata as defined in Section 5.4.2
o (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 (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 (OPTIONAL), The user friendly name that is assigned
to the secret key for easy reference. The FriendlyName is defined
as a String.
o (OPTIONAL), the element carrying the data related to the
key as defined in Section 5.4.1
o (OPTIONAL), the policy of the PIN relating to the
usage of this key as defined in Section 5.4.4
o (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 (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 (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 (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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blahblahblah
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 hence obey a simple structure in that they
MUST have:
a choice between:
A element that is typed to the specific type (e.g.
xs:integer)
An element that is of type xenc:EncryptedDataType
where the value of the specific element is placed in case it is
encrypted
an optional 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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The following typed base types have been defined within the current
schema of the PSKC spec with the naming convention 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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The elements of the Data element have the following meanings:
o (OPTIONAL), the value of the key itself in binary.
o (OPTIONAL), the event counter for event based OTP
algorithms.
o
8.4.4.6. SecurID-AES-Counter
Common Name: SecurID-AES-Counter
Class: OTP
URI: http://www.rsa.com/names/2008/04/algorithms/SecurID/
SecurID-AES128-Counter
Algorithm Definition: http://www.rsa.com/names/2008/04/algorithms/
SecurID/SecurID-AES128-Counter
Identifier Definition http://www.rsa.com/names/2008/04/algorithms/
SecurID/SecurID-AES128-Counter
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Registrant Contact: Andrea Doherty, RSA the Security Division of
EMC,
Profile of XML attributes and subelements of the entity:
For a of this algorithm, the , , and
sub-elements MUST be present. The "OTP" attribute of
MUST be set to "true" and it MUST be the only attribute
set. The sub-element of MUST be used to
indicate the OTP length and the value format.
For the Data elements of a of this algorithm, the following
subelements MUST be present in either the element itself or
an commonly shared element.
* Counter
The following additional constraints apply:
- The value of the element MUST contain key material
with a lengthy of at least 16 octets (128 bits) if it is
present.
- The element MUST have the 'Format' attribute
set to "DECIMAL", and the 'Length' attribute MUST be set to a
minimum value of 6.
- The and elements MUST be of type
.
- The element MAY be present but the child
element of the element cannot be set to
"Algorithmic".
An example of a of this algorithm is as follows.
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RSA, The Security Division of EMC123456798Issuer2006-04-14T00:00:00Z2010-09-30T00:00:00ZMTIzNDU2Nzg5MDEyMzQ1Njc4OTA=
0
8.4.4.7. SecurID-ALGOR
Common Name: SecurID-ALGOR
Class: OTP
URI: http://www.rsasecurity.com/rsalabs/otps/schemas/2005/09/
otps-wst#SecurID-ALGOR
Algorithm Definition: http://www.rsa.com/rsalabs/node.asp?id=2821
Identifier Definition: http://www.rsa.com/rsalabs/node.asp?id=2821
Registrant Contact: Andrea Doherty, RSA the Security Division of
EMC,
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Profile of XML attributes and subelements of the entity:
For a of this algorithm, the , , and
sub-elements MUST be present. The "OTP" attribute of
MUST be set to "true" and it MUST be the only attribute
set. The sub-element of MUST be used to
indicate the OTP length and the value format.
The following additional constraints apply:
- The value of the element MUST contain key material
with a lengthy of at least 8 octets (64 bits) if it is present.
- The element MUST have the 'Format' attribute
set to "DECIMAL", and the 'Length' attribute MUST be set to a
value of 6 through 8.
- The and elements MUST be of type
.
- The element MAY be present but the child
element of the element cannot be set to
"Algorithmic".
An example of a of this algorithm is as follows.
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RSA, The Security Division of EMC123456798Issuer2006-04-14T00:00:00Z2010-09-30T00:00:00Z
8.4.4.8. ActivIdentity-3DES
Common Name: ActivIdentity-3DES
Class: OTP
URI: http://www.actividentity.com/2008/04/algorithms/
algorithms#ActivIdentity-3DES
Algorithm Definition: http://www.actividentity.com/2008/04/
algorithms/algorithms#ActivIdentity-3DES
Identifier Definition http://www.actividentity.com/2008/04/
algorithms/algorithms#ActivIdentity-3DES
Registrant Contact: Philip Hoyer, ActivIdentity Inc,
Profile of XML attributes and subelements of the entity:
For a of this algorithm, the subelements MUST be
present. This algorithm can be used for otp, challenge response,
parameter based MACing (integrity) and to generate a device unlock
code (n case of devices where there is local PIN management and
the devce has been locked after a specific amount of wrong PIN
entry attempts). Hence the "OTP", "CR","Integrity" and "Unlock"
attribute of the can be set to "true", but at least one of
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the above MUST be set to true. The element of
the MUST be used to indicate the OTP length, the value
format and optionally if a check digit is being used. If the use
is challenge-response then the of the
MUST be used to indicate the challenge minimum and maximum length,
its format and optionally if a check digit is being used.
For the elements of a of this algorithm, the
following subelements MUST be present in either the element
itself or an commonly shared element.
* Secret
* Counter
* Time
* TimeInterval
The following additional constraints apply:
- The value of the element MUST contain key material
with a length of at least 16 octets (Double DES keys 128 bits
including parity) if it is present.
- The element MUST have the 'Format' attribute
set to "DECIMAL" or "HEXADECIMAL", and the 'Length' attribute
MUST be between 6 and 16.
- The element MUST have the 'Format'
attribute set to "DECIMAL", and the 'Min' and 'Max' attributes
be between 4 and 16 (The Min attribute MUST be equal or less
than the Max).
- The element MAY be present but the child
element of the element cannot be set to
"Algorithmic".
An example of a Key of this algorithm is as follows.
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ActivIdentity34567890Issuer
MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=
00320
8.4.4.9. ActivIdentity-AES
Common Name: ActivIdentity-AES
Class: OTP
URI: http://www.actividentity.com/2008/04/algorithms/
algorithms#ActivIdentity-AES
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Algorithm Definition: http://www.actividentity.com/2008/04/
algorithms/algorithms#ActivIdentity-AES
Identifier Definition http://www.actividentity.com/2008/04/
algorithms/algorithms#ActivIdentity-AES
Registrant Contact: Philip Hoyer, ActivIdentity Inc,
Profile of XML attributes and subelements of the entity:
For a of this algorithm, the subelements MUST be
present. This algorithm can be used for otp, challenge response,
parameter based MACing (integrity) and to generate a device unlock
code (n case of devices where there is local PIN management and
the devce has been locked after a specific amount of wrong PIN
entry attempts). Hence the "OTP", "CR","Integrity" and "Unlock"
attribute of the can be set to "true", but at least one of
the above MUST be set to true. The element of
the MUST be used to indicate the OTP length, the value
format and optionally if a check digit is being used. If the use
is challenge-response then the of the
MUST be used to indicate the challenge minimum and maximum length,
its format and optionally if a check digit is being used.
For the elements of a key of this algorithm, the following
subelements MUST be present in either the element itself or
an commonly shared element.
* Secret
* Counter
* Time
* TimeInterval
The following additional constraints apply:
- The value of the element MUST contain key material
with a length of at least 16 octets (128 bits) if it is
present.
- The element MUST have the 'Format' attribute
set to "DECIMAL" or "HEXADECIMAL", and the 'Length' attribute
MUST be between 6 and 16.
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- The element MUST have the 'Format'
attribute set to "DECIMAL", and the 'Min' and 'Max' attributes
be between 4 and 16 (The Min attribute MUST be equal or less
than the Max).
- The element MAY be present but the child
element of the element cannot be set to
"Algorithmic".
An example of a of this algorithm is as follows.
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ActivIdentity34567890Issuer
MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=
00320
8.4.4.10. ActivIdentity-DES
Common Name: ActivIdentity-DES
Class: OTP
URI: http://www.actividentity.com/2008/04/algorithms/
algorithms#ActivIdentity-DES
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Algorithm Definition: http://www.actividentity.com/2008/04/
algorithms/algorithms#ActivIdentity-DES
Identifier Definition http://www.actividentity.com/2008/04/
algorithms/algorithms#ActivIdentity-DES
Registrant Contact: Philip Hoyer, ActivIdentity Inc,
Profile of XML attributes and subelements of the entity:
For a of this algorithm, the subelements MUST be
present. This algorithm can be used for otp, challenge response,
parameter based MACing (integrity) and to generate a device unlock
code (n case of devices where there is local PIN management and
the devce has been locked after a specific amount of wrong PIN
entry attempts). Hence the "OTP", "CR","Integrity" and "Unlock"
attribute of the can be set to "true", but at least one of
the above MUST be set to true. The element of
the MUST be used to indicate the OTP length, the value
format and optionally if a check digit is being used. If the use
is challenge-response then the of the
MUST be used to indicate the challenge minimum and maximum length,
its format and optionally if a check digit is being used.
For the elements of a key of this algorithm, the following
subelements MUST be present in either the element itself or
an commonly shared element.
* Counter
* Time
* TimeInterval
The following additional constraints apply:
- The value of the element MUST contain key material
with a length of at least 8 octets (56 bits + parity) if it is
present.
- The element MUST have the 'Format' attribute
set to "DECIMAL" or "HEXADECIMAL", and the 'Length' attribute
MUST be between 6 and 16.
- The element MUST have the 'Format'
attribute set to "DECIMAL", and the 'Min' and 'Max' attributes
be between 4 and 16 (The Min attribute MUST be equal or less
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than the Max).
- The element MAY be present but the child
element of the element cannot be set to
"Algorithmic".
An example of a of this algorithm is as follows.
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ActivIdentity34567890Issuer
MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=
00320
8.4.4.11. ActivIdentity-EVENT
Common Name: ActivIdentity-EVENT
Class: OTP
URI: http://www.actividentity.com/2008/04/algorithms/
algorithms#ActivIdentity-EVENT
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Algorithm Definition: http://www.actividentity.com/2008/04/
algorithms/algorithms#ActivIdentity-EVENT
Identifier Definition http://www.actividentity.com/2008/04/
algorithms/algorithms#ActivIdentity-EVENT
Registrant Contact: Philip Hoyer, ActivIdentity Inc,
Profile of XML attributes and subelements of the entity:
For a of this algorithm, the subelements MUST be
present. This algorithm can be used for otp, challenge response,
parameter based MACing (integrity) and to generate a device unlock
code (n case of devices where there is local PIN management and
the device has been locked after a specific amount of wrong PIN
entry attempts). Hence the "OTP", "CR","Integrity" and "Unlock"
attribute of the can be set to "true", but at least one of
the above MUST be set to true. The element of
the MUST be used to indicate the OTP length, the value
format and optionally if a check digit is being used. If the use
is challenge-response then the of the
MUST be used to indicate the challenge minimum and maximum length,
its format and optionally if a check digit is being used.
For the elements of a key of this algorithm, the following
subelements MUST be present in either the element itself or
an commonly shared element.
* Counter
The following additional constraints apply:
- The value of the element MUST contain key material
with a length of at least 8 octets (56 bits + parity) if it is
present.
- The element MUST have the 'Format' attribute
set to "DECIMAL" or "HEXADECIMAL", and the 'Length' attribute
MUST be between 6 and 16.
- The element MAY be present but the child
element of the element cannot be set to
"Algorithmic".
An example of a of this algorithm is as follows.
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ActivIdentity34567890Issuer
MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=
0
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9. Security Considerations
The portable key container carries sensitive information (e.g.,
cryptographic keys) and may be transported across the boundaries of
one secure perimeter to another. For example, a container residing
within the secure perimeter of a back-end provisioning server in a
secure room may be transported across the internet to an end-user
device attached to a personal computer. This means that special care
must be taken to ensure the confidentiality, integrity, and
authenticity of the information contained within.
9.1. Payload confidentiality
By design, the container allows two main approaches to guaranteeing
the confidentiality of the information it contains while transported.
First, the container key data payload may be encrypted.
In this case no transport layer security is required. However,
standard security best practices apply when selecting the strength of
the cryptographic algorithm for payload encryption. Symmetric
cryptographic cipher should be used - the longer the cryptographic
key, the stronger the protection. At the time of this writing both
3DES and AES are mandatory algorithms but 3DES may be dropped in the
relatively near future. Applications concerned with algorithm
longevity are advised to use AES-256-CBC. In cases where the
exchange of key encryption keys between the sender and the receiver
is not possible, asymmetric encryption of the secret key payload may
be employed. Similarly to symmetric key cryptography, the stronger
the asymmetric key, the more secure the protection is.
If the payload is encrypted with a method that uses one of the
password-based encryption methods provided above, the payload may be
subjected to password dictionary attacks to break the encryption
password and recover the information. Standard security best
practices for selection of strong encryption passwords apply
[Schneier].
Practical implementations should use PBESalt and PBEIterationCount
when PBE encryption is used. Different PBESalt value per key
container should be used for best protection.
The second approach to protecting the confidentiality of the payload
is based on using transport layer security. The secure channel
established between the source secure perimeter (the provisioning
server from the example above) and the target perimeter (the device
attached to the end-user computer) utilizes encryption to transport
the messages that travel across. No payload encryption is required
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in this mode. Secure channels that encrypt and digest each message
provide an extra measure of security, especially when the signature
of the payload does not encompass the entire payload.
Because of the fact that the plain text payload is protected only by
the transport layer security, practical implementation must ensure
protection against man-in-the-middle attacks [Schneier]. Validating
the secure channel end-points is critically important for eliminating
intruders that may compromise the confidentiality of the payload.
9.2. Payload integrity
The portable symmetric key container provides a mean to guarantee the
integrity of the information it contains through digital signatures.
For best security practices, the digital signature of the container
should encompass the entire payload. This provides assurances for
the integrity of all attributes. It also allows verification of the
integrity of a given payload even after the container is delivered
through the communication channel to the target perimeter and channel
message integrity check is no longer possible.
9.3. Payload authenticity
The digital signature of the payload is the primary way of showing
its authenticity. The recipient of the container may use the public
key associated with the signature to assert the authenticity of the
sender by tracing it back to a preloaded public key or certificate.
Note that the digital signature of the payload can be checked even
after the container has been delivered through the secure channel of
communication.
A weaker payload authenticity guarantee may be provided by the
transport layer if it is configured to digest each message it
transports. However, no authenticity verification is possible once
the container is delivered at the recipient end. This approach may
be useful in cases where the digital signature of the container does
not encompass the entire payload.
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10. Acknowledgements
The authors of this draft would like to thank the following people
for their contributions and support to make this a better
specification: Apostol Vassilev, Shuh Chang, Jon Martinson, Siddhart
Bajaj, Stu Veath, Kevin Lewis, Philip Hallam-Baker, Hannes
Tschofenig, Andrea Doherty, Magnus Nystrom, Tim Moses, Anders
Rundgren, Sean Turner and especially Robert Philpott.
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11. Appendix A - Example Symmetric Key Containers
All examples are syntactically correct and compatible with the XML
schema in section 7. The examples will be revised as the test
vectors for implementation interoperability verification. Two of the
examples below carry some sample test inputs.
11.1. Symmetric Key Container with a single Non-Encrypted HOTP Secret
Key
Assume the following test data:
OTP Secret Key Hex Value (20 bytes):
0x3132333435363738393031323334353637383930
Sample KeyContainer:
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TokenVendorAcme987654321Issuer2006-04-14T00:00:00Z2010-09-30T00:00:00Z
MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=
0
11.2. Symmetric Key Container with a single PIN protected Non-Encrypted
HOTP Secret Key
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TokenVendorAcme0755225266AnIssuer
MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=
0
MTIzNA==
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11.3. Symmetric Key Container with a single AES-128-CBC Encrypted HOTP
Secret Key and non-encrypted counter value
Assume the following test data:
OTP Secret Key Hex Value (20 bytes):
0x3132333435363738393031323334353637383930
AES Key Hex Value (16 bytes): 0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b
The MAC key is the same as the AES encryption key.
The sample KeyContainer:
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PRE_SHARED_KEYhttp://www.w3.org/2000/09/xmldsig#hmac-sha1
TokenVendorAcme0755225266AnIssuerxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxx0
11.4. Symmetric Key Container with signature and a single Password-
based Encrypted HOTP Secret Key
Passphrase1P1ciQdGbrI0=200016TokenVendorAcme0755225266AnIssuerrf4dx3rvEPO0vKtKL14NbeVu8nk=
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0j6lwx3rvEPO0vKtMup4NbeVu8nk=
j6lwx3rvEPO0vKtMup4NbeVu8nk=
CN=KeyProvisioningUs.com,C=US
12345678
11.5. Symmetric Key Container with a single RSA 1.5 Encrypted HOTP
Secret Key
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miibTokenVendorAcme0755225266AnIssuerrf4dx3rvEPO0vKtKL14NbeVu8nk=
0
11.6. Symmetric Key Container with a single AES-128-CBC Encrypted OCRA
Secret Key and non-encrypted counter value
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Pre-shared-key
http://www.w3.org/2000/09/xmldsig#hmac-sha1
TokenVendorAcme987654321Issuer
gVc5jCsntSD1rhIgwWxmWNvEIkpTgn0E6+OH5mDPAok=
JIOeKMISfMTy7og7Saq0CZrLdfE=0
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11.7. Symmetric Key Container with a single AES-256-CBC Encrypted TOTP
Secret Key and non-encrypted time values
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PRE_SHARED_KEYhttp://www.w3.org/2000/09/xmldsig#hmac-sha1
TokenVendorAcme0755225266AnIssuer
gVc5jCsntSD1rhIgwWxmWNvEIkpTgn0E6+OH5mDPAok=
JIOeKMISfMTy7og7Saq0CZrLdfE=0304
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11.8. Symmetric Key Container with two devices containing a Non-
Encrypted HOTP Secret Key each sharing common KeyProperties
Issuer0TokenVendorAcme987654321
MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=
TokenVendorAcme987654322
MTIzNDU2Nzg5MDEyMzQ1Njc4OTA=
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12. References
12.1. Normative References
[LUHN] Luhn, H., "Luhn algorithm", US Patent 2950048,
August 1960, .
[PKCS1] Kaliski, B., "PKCS #1: RSA Cryptography Specifications
Version 2.0.", RFC 2437, October 1998.
[PKCS5] RSA Laboratories, "PKCS #5: Password-Based Cryptography
Standard", Version 2.0,
URL: http://www.rsasecurity.com/rsalabs/pkcs/, March 1999.
[RFC2119] "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media
Types", RFC 3023, January 2001.
[RFC3553] Mealling, M., Masinter, L., Hardie, T., and G. Klyne, "An
IETF URN Sub-namespace for Registered Protocol
Parameters", BCP 73, RFC 3553, June 2003.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and
Registration Procedures", BCP 13, RFC 4288, December 2005.
[RFC4514] Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP): String Representation of Distinguished Names",
RFC 4514, June 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[XMLDSIG] Eastlake, D., "XML-Signature Syntax and Processing",
URL: http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/,
W3C Recommendation, February 2002.
[XMLENC] Eastlake, D., "XML Encryption Syntax and Processing.",
URL: http://www.w3.org/TR/xmlenc-core/,
W3C Recommendation, December 2002.
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12.2. Informative References
[AlgorithmURIs]
Eastlake, D., "Additional XML Security Uniform Resource
Identifiers", RFC 4051, April 2005.
[CAP] MasterCard International, "Chip Authentication Program
Functional Architecture", September 2004.
[DSKPP] Doherty, A., Pei, M., Machani, S., and M. Nystrom,
"Dynamic Symmetric Key Provisioning Protocol", Internet
Draft Informational, URL: http://www.ietf.org/
internet-drafts/draft-ietf-keyprov-dskpp-05.txt,
February 2008.
[HOTP] MRaihi, D., Bellare, M., Hoornaert, F., Naccache, D., and
O. Ranen, "HOTP: An HMAC-Based One Time Password
Algorithm", RFC 4226, December 2005.
[NIST-SP800-57]
National Institute of Standards and Technology,
"Recommendation for Key Management - Part I: General
(Revised)", NIST 800-57, URL: http://csrc.nist.gov/
publications/nistpubs/800-57/
sp800-57-Part1-revised2_Mar08-2007.pdf, March 2007.
[OATH] "Initiative for Open AuTHentication",
URL: http://www.openauthentication.org.
[OCRA] MRaihi, D., Rydell, J., Naccache, D., Machani, S., and S.
Bajaj, "OCRA: OATH Challenge Response Algorithm", Internet
Draft Informational, URL: http://www.ietf.org/
internet-drafts/
draft-mraihi-mutual-oath-hotp-variants-06.txt,
December 2007.
[PKCS12] RSA Laboratories, "PKCS #12: Personal Information Exchange
Syntax Standard", Version 1.0,
URL: http://www.rsasecurity.com/rsalabs/pkcs/.
[Schneier]
Schneier, B., "Secrets and Lies: Digitial Security in a
Networked World", Wiley Computer Publishing, ISBN 0-8493-
8253-7, 2000.
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Authors' Addresses
Philip Hoyer
ActivIdentity, Inc.
117 Waterloo Road
London, SE1 8UL
UK
Phone: +44 (0) 20 7744 6455
Email: Philip.Hoyer@actividentity.com
Mingliang Pei
VeriSign, Inc.
487 E. Middlefield Road
Mountain View, CA 94043
USA
Phone: +1 650 426 5173
Email: mpei@verisign.com
Salah Machani
Diversinet, Inc.
2225 Sheppard Avenue East
Suite 1801
Toronto, Ontario M2J 5C2
Canada
Phone: +1 416 756 2324 Ext. 321
Email: smachani@diversinet.com
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Full Copyright Statement
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