Re: [KEYPROV] [pskc] Latest draft of PSKC

Another day another edition.

I realized that the IntegerDataType was actually creating BigIntegers in java since it was of type xs:integer and hence have changed it to xs:int to more reflect what we need. And I have also renamed it to intDataType to be in line with the longDataType used for counters.

The OCRA example was also corrected and some nits from Sean Turner abut different spelling of crypto modules in the use cases.

Philip

Please find attached the latest work in progress draft and related schema after the additions that address Robert Philpott’s latest comments (if they resulted in changes to existing changes from draft -04 they have been prefixed [UPDATE]),

TODOs:

Hannes to change the IANA section relating XML tag registry since not needed anymore
Review the spec (Salah, Hannes, Andrea) especially the wording around the new changes (please see KeyData Element definition in the new spec)
Add additional elements under KeyData based on input from Rob Philpot
Review extension points are correct

Changes made from version 4 are:

[UPDATE] Added optional Id element to the container in case another document includes more than one container and wants to reference it uniquely, this is of type xs:Id named ‘ID’
Made PINKeyId of PINPolicy optional (in version 4 it wrongly became mandatory)
Changed KeyPropertiesType:KeyPropertiesId from type xs:String to xs:ID
[UPDATE] Changed KeyType:KeyPropertiesId from type xs:string to be of type xs:IDREF as it refers to the ID of the element of (3) see directly above, also renamed to simply KeyProperties
[UPDATE] Removed PINPolicyId as not needed, Added optional PINPolicyId attribute of type xs:ID to PINPolicyType -
Added the KeyContainer:KeyProperties element that was missing from version -04 (oversight).This is where the common properties for a key are actually held within a container
Changed PINPolicyType: WrongPINtry into WrongPINTry so that it is proper camel-case but the discussed naming and changed to ‘MaxFailedAttempts’
Changed PINUsageMode ‘InAlgo’ to ‘Algorithmic’
Added description for added extension points (see below)
Changed DeviceIdType to DeviceInfoType (please see other email for rational to keep separate type and not move elements directly under Device)
Moved Keyporperties in front of device under KeyContainer for more readability
Changed Namespace as per Hannes proposal from "urn:ietf:params:xml:ns:keyprov:container:1.0" to “urn:ietf:params:xml:ns:keyprov:pskc:1.0"
Cleaned up the way that attributes (no angled brackets) and elements (angled brackets <elementName>) are described in the spec
Corrected some spelling and grammar
Changed schema and spec to new proposal that removes name value pairs
Added OCRA URI to the spec and added an example
Added TOTP URI to the spec and added an example
Added an example of KeyProperties
Added ‘Append’ to PIN for completeness.
Corrected the wrong ‘MANDATORY’ in the usage description of KeyType and KeyPropertiesType
Added the following comment the elements of type xs:dateTime: “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.”
Moved StartDates before ExpiryDates for easier readability
Added the following sub-elements to PINPolicyType
1. <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.
2. <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 digits/characters. If the Format attribute is 'BASE64' or 'BINARY', this value indicates the number of bytes of the unencoded value.
3. <Format (OPTIONAL)>, defines the format of the PIN and MUST be one of the values defined in Section 5.4.3

[Update] Extension points:

Changed to model proposed by Rob Philpott declaring a new type:

<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>

Which has been added as “<xs:element name="Extensions" type="pskc:ExtensionsType" minOccurs="0" maxOccurs="unbounded"/>”

To:

KeyContainerType
KeyPropertiesType
KeyType
PINPolicy
DeviceInfoType
DeviceType
UsageType

Please NOTE that KeyData still has the existing “<xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>”

Because of the special nature of the KeyData element and subelements

PINUsageMode too maintains the existing “<xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>”

Being an extensible enumeration

Added a ‘<xs:anyAttribute namespace="##other"/>’ to:

UsageType (since it contains the attributes of ‘

<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"/>

So I thought it would be wise to be able to extend this

Outstanding issues that need to be discussed:

Most of the examples have been hand-composed in XML so not verified
Some examples use explicit ‘pskc:’ namespace not sure we need to do this but maybe we should be consistent

Philip

From: andrea.doherty at rsa.com [mailto:andrea.doherty at rsa.com]
Sent: Friday, May 30, 2008 4:36 PM
To: keyprov at ietf.org
Cc: Philip Hoyer
Subject: FW: [KEYPROV] [pskc] Latest draft of PSKC

Here is Philip Hoyer's response to Rob's comments (see below), which we initially handled offline, and then we decided it would be better to further the discussion on the mailing list.

-- Andrea

1. Use of xs:ID attributes:

a. The xs:ID datatype is only used in the DerivedKeyType complexType. xs:ID is the preferred mechanism for referring to other XML elements in an instance document. So why are custom attributes defined to be able to referto elements of the types KeyPropertiesType (the “KeyPropertiesId” attribute) and KeyType (“KeyId”)? Why don’t these use xs:ID attributes?

[PH] good point I was thinking that xs:Id for KeyPropertiesId could be a good choice The KeyId on the other hand is not really used to be referred to. Do you think it would be better to use xs:ID for this aswell? And in case we use it now is it backwards compatible to what we have?

b. Why doesn’t a KeyContainer have an (optional) ID that could be used to reference it in an instance document?

[PH] valid comment and I will think we should add this

c. Same question for PINPolicy?

[PH] agreed

d. The use of the DeviceIdType is inconsistent with other “ID”’s (that are used for referential information). The elements in the DeviceIDType seem more appropriate for the DeviceType or KeyType elements. At a minimum, I would not call this a “DeviceIdType” (perhaps “DeviceInfoType”?) but really, I would just put its elements directly in the DeviceType complexType). I would also give <Device> elements an optional referential ID via xs:ID.

[PH] so basically you are saying that any high level entity (Key, Device, KeyContainer etc) should have an ID that is xs:ID? The thought of DeviceId was to aggregate under a specific type the elements that comprise the compound key to look up the device

e. Section 5.2.1 says that the DeviceIdType is an extensible type, but there are no extension points in it.

[PH] agreed I think we should add an xs:any

2. We are really unhappy with the proposed extensibility mechanism. This goes against general XML schema best practice. Defining extension points via xs:any/xs:anyAttribute is vastly superior (IMO):

[PH] this has been extensively discussed at IETF and there are pros and cons for all approaches. The pro’s of the name value approach is that it will be re-usable for the ASN.1 spec and that we will have a semantic registry defined by IANA.

a. The use of “Reserved data attribute names” as described in section 7 is really difficult to work with. First, <Data> elements should ONLY be used for “real” extensions… i.e. things that aren’t already known at the time the spec is written. If we already know that the items defined in section 7 are needed, they should just be defined in the schema with their own element/attribute definitions. They should not be “reserved” uses of the <DATA> element. We just don’t understand the desire to do it this way. Having explicitly defined elements also allows for more flexible datayping.

[PH] this has been extensively discussed. And we opted for the name value pair approach. This mean that all elements in Data can be parsed in the same manner and individually be encrypted or not. There will be a centralized semantic registry by IANA, etc

b. This mechanism only lets us create very simple name-value pair extensions. If we have some small groups of related extensions, we’d really like to be able to define them externally in a private schema via their own complexType definitions. With the current method, it’s going to be very messy to add groups of extensions or extensions that have more complex data values.

[PH] why do you say that, the name could be also be a namespace for an wholly encrypted or base64 encoded XML sub node. I see your point though in terms of parsing here. Could you give me an example of what you had in mind since we have considered quite a few use cases and not come across the requirement for grouped extensions.

c. It is also a pain for implementers to deal with the limitation of the data typing available for unencrypted <Data> elements. For example, for a SecurID token with a display interval of 60 seconds, I cannot simply use an xml schema-defined datatype of xs:integer with a value of “60”. I have to Base64-encode the big-endian 2-byte binary value for 60 seconds (and then decode it on the receiving end). Why is this necessary? I could define such an item with a single XML element, but here I need 3 or 4.

[PH] using xs:string for plainvalue was discussed during the last IETF meeting (I personally am in favor of it) but Sean Turner and the rest of the people did not see much value in it. If we use string we will need to deice for specific data elements what the encoding rules are. For example do we say for 8 byte unsigned int to encode just string e.g. ‘60’ or leading 0 examples ‘00000060’. I would appreciate your thoughts on this. Also how would we encode binary data in string form base64 encoded?

d. This approach does not produce “readable” XML since the data values are always Base64-encoded. That is just crazy when the data is not sensitive in nature. Please do not underestimate the value of being able to look at data in an instance document and know what it is without having to run it through a Base64 decoder! This is a major drawback.

[PH] agreed and see answer above

3. RE: PINPolicy:

a. If I specify a PINPolicy, I am forced to specify a PINKeyID, which forces me to create another Key element (even if I don’t have any additional PIN policy info that I need to pass along in that Key element). For 90% of the use cases, this referential style of description is overkill and makes the instance document much more complex than it needs to be.

[PH] if you are referring to the fact that ‘<xs:attribute name="PINKeyId" type="xs:string" use="required"/>’ is set to required I agree with you. We should set this to ‘optional’. I do not agree with your 90% use case analysis since the main use cases I have come across where to transmit the initial random pin for PINPads tokens within the same PSKC document from manufacturing to the validation server.

b. The PINPolicy element only contains “policy” attributes for “WrongPINtry” and “PINUsageMode” and the element is not directly extensible. Any extensions we need have to go in Data elements inside a separate Key element that the PINPolicy then references. IMO, PIN policy info should be in the PINPolicy element, not in a separate “Key” element! The only thing that should go in the Key element is a PIN value that is being expressly communicated with the instance document. That is, a PIN value IS a key; PIN policy information IS NOT a key.

[PH] I agree we need to make PINPolicy extensible and not put stuff into the Data elements of the PINKey. Are there any other elements that you know of we should include now and not just as an xs:any extension?

c.       It seems to us that there are additional universally-known PIN policy attributes that should be included in the schema. Things such as the PIN’s maximum and minimum length and it’s data type (integer, alphanumeric). Unless these are part of the spec, we currently are forced to create custom Data elements for them (and put them in a referenced Key element). BTW – Just to be clear, I am talking about the POLICY information associated with whatever PIN a user uses with their token. I’m not talking about the attributes of a specific PIN value that can be expressed in a Key element. As an example, to express a min and max PIN length policy, we have to create custom Data elements in a separate Key element (and also Base64 encode the values). I’m sorry, but this is getting ridiculous.

           <Key KeyId="07552252661"

             KeyAlgorithm="http://www.ietf.org/keyprov/pskc#pin">

              <Data Name="PIN_MIN_LENGTH">

                  <PlainValue>NA==</PlainValue>

              </Data>

              <Data Name="PIN_MAX_LENGTH">

                  <PlainValue>OA==</PlainValue>

              </Data>

           </Key>

[PH] no the format and length would be in the UsageElement of the PINKey. I had hoped Example (Section 12.2 of the spec) would make that clear here is the XML fragment:

<Key KeyId="07552252661"

KeyAlgorithm="http://www.ietf.org/keyprov/pskc#pin">

<Usage>

</Usage>

<PlainValue>MTIzNA==</PlainValue>

</Data>

        </Key>

Notes:

a.       If I had an xs:any extension point, I could express this in 2 lines of XML in the PinPolicy element.

b.      This example doesn’t include the PIN format, which would require me to either:

                                                                     i.            Use another custom Data element

                                                                   ii.            Include a ResponseFormat element that then requires inclusion of a “Length” attribute. But what would the Length attribute really mean in this case?

d.      Why isn’t a PINPolicy reusable across multiple tokens (it has no ID that can be used in a reference from a token definition). If I want to define a PINPolicy that applies to multiple tokens, the PINPolicy element needs its own ID.

[PH] I see your point. If we make PINKeyId optional as in the comment above you can have a common PINPolicy as part of the shared KeyProperties. I believe that would serve your purpose.

e. The “WrongPINtry” element name (in PINPolicyType) is not consistent with the other camel-case names (“try” should be “Try”).

[PH] agreed, will change

f. In general, it is undesirable to create abbreviations such as “InAlgo” (in PINUsageMode) to be used as XML keywords. To stay consistent with “Local” and “Prepend”, I would strongly suggest something like “Embed” or “Algorithmic”.
[PH[ we had Embed before and people got confused by the meaning. So maybe Algorithmic is a better choice, that is why I tried to express the use of the PIN in the algorithm as InAlgo. I do not feel very strong about it. Maybe we can have a vote

4. The use of “ResponseFormat” for describing a PIN is very confusing. The spec defines ResponseFormat as follows “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.” A PIN is not the result of a “computation”, nor is it a response to a challenge. It seems quite odd to use this Key construct for a PIN. I think that either another usage type should be defined or the ResponseFormat definition should be changed to also reflect its use for describing a PIN.
[PH] Yes I think we need to change the description. I am getting a lot of push back to include PIN requirements in the spec so I tried to convince people that tit was a good idea without having to introduce to many new schema types. Here you say it is odd to use the Key element for the PIN value but above you agree that a PIN IS a Key. So I would keep it in the Key element buy change description.

<?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?> <!DOCTYPE rfc SYSTEM "rfc2629.dtd" [ <!ENTITY rfc2119 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml'> ]> <rfc category="std" ipr="full3978" docName="draft-ietf-keyprov-portable-symmetric-key-container-05.txt"> <?rfc toc="yes" ?> <?rfc symrefs="yes" ?> <?rfc sortrefs="yes"?> <?rfc iprnotified="no" ?> <?rfc strict="yes" ?> <front> <title>Portable Symmetric Key Container</title> <author initials="P." surname="Hoyer" fullname="Philip Hoyer"> <organization abbrev="ActivIdentity"> ActivIdentity, Inc. </organization> <address> <postal> <street>117 Waterloo Road</street> <city>London</city> <region>SE1</region> <code>8UL</code> <country>UK</country> </postal> <phone>+44 (0) 20 7744 6455</phone> <email>Philip.Hoyer at actividentity.com</email> </address> </author> <author initials="M." surname="Pei" fullname="Mingliang Pei"> <organization abbrev="VeriSign"> VeriSign, Inc. </organization> <address> <postal> <street>487 E. Middlefield Road</street> <city>Mountain View</city> <region>CA</region> <code>94043</code> <country>USA</country> </postal> <phone>+1 650 426 5173</phone> <email>mpei at verisign.com</email> </address> </author> <author initials="S." surname="Machani" fullname="Salah Machani"> <organization abbrev="Diversinet"> Diversinet, Inc. </organization> <address> <postal> <street>2225 Sheppard Avenue East</street> <street>Suite 1801</street> <city>Toronto</city> <region>Ontario</region> <code>M2J 5C2</code> <country>Canada</country> </postal> <phone>+1 416 756 2324 Ext. 321</phone> <email>smachani at diversinet.com</email> </address> </author> <date day="09" month="July" year="2008"/> <workgroup>keyprov</workgroup> <abstract> <t>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. </t> <t>This work is a joint effort 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.</t> </abstract> </front> <middle> <section title="Introduction"> <t>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.</t> <t>This Internet draft 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.</t> <t>This draft also specifies the key attributes required for computation such as the initial event counter used in the HOTP algorithm <xref target="HOTP"/>. It is also applicable for other time-based or proprietary algorithms. </t> <t>To provide an analogy, in public key environments the PKCS#12 format <xref target="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, a format with small (size in bytes) and explicit shared secret configuration attribute information is desirable, avoiding complexity of PKCS#12. For example, one would have to use opaque data within PKCS#12 to carry shared secret attributes used for OTP calculations, whereas a more explicit attribute schema definition is better for interoperability and efficiency.</t> </section> <section title="Terminology"> <section title="Key Words"> <t>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 <xref target="RFC2119"/>.</t> </section> <section title="Definitions"> <t>This section defines terms used in this document. The same terms may be defined differently in other documents. <list style="hanging"> <t hangText="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.</t> <t hangText="Bulk Provisioning:">Transferring multiple keys linked to multiple devices in a single execution step within one single PSKC KeyContainer</t> <t hangText="Cryptographic Module:">A component of an application, which enables symmetric key cryptographic functionality</t> <t hangText="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 <xref target="NIST-SP800-57"/>)</t> <t hangText="Cryptographic Token:">See Authentication Token</t> <t hangText="Device:">A physical piece of hardware, or a software framework, that hosts symmetric keys</t> <t hangText="DeviceInfo:">A set of elements whose values combined uniquely identify a device e.g. Manufacture 'Manufacturer and Serialnumber '12345678'</t> <t hangText="Dynamic Provisioning:">Usage of a protocol, such as DSKPP, to make a key container available to a recipient</t> <t hangText="Encryption Key:">A key used to encrypt key</t> <t hangText="Key:">See Cryptographic Key</t> <t hangText="Hardware Token:">See Authentication Token</t> <t hangText="Key Algorithm:">A well-defined computational procedure that takes variable inputs including a cryptographic key and produces an output.</t> <t hangText="Key Container:">An object that encapsulates symmetric keys and their attributes for set of devices</t> <t hangText="Key ID (KeyID):">A unique identifier for the symmetric key</t> <t hangText="Key Issuer:">An organization that issues symmetric keys to end-users</t> <t hangText="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.)</t> <t hangText="Secret Key:">The symmetric key data</t> <t hangText="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 </t> <t hangText="Token:">See Authentication Token</t> <t hangText="User:">The person or client to whom devices are issued</t> <t hangText="User ID:">A unique identifier for the user or client</t> </list></t> </section> </section> <section title="Use Cases"> <t>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.</t> <t>These use cases also help in understanding the applicability of this specification to real world situations.</t> <section title="Online Use Cases"> <t>This section describes the use cases related to provisioning the keys using an online provisioning protocol such as <xref target="DSKPP"/></t> <section title="Transport of keys from Server to Cryptomodule"> <t>For example, a mobile device user wants to obtain a symmetric key for use with a cryptomodule on the device. The cryptomodule client from vendor A initiates the provisioning process against a provisioning system from vendor B using a standards-based provisioning protocol such as <xref target="DSKPP"/>. The provisioning entity delivers one or more keys in a standard format that can be processed by the mobile device.</t> <t>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.</t> <t>For example, the end-user or the key issuer wants to update or configure an existing key in the cryptomodule and requests a replacement key container. The container may or may not include a new key and may include new or updated key attributes such as a new counter value in HOTP key case, a modified response format or length, a new friendly name, etc.</t> </section> <section title="Transport of keys from Cryptomodule to Cryptomodule"> <t>For example, a user wants to transport a key from one cryptomodule to another. There may be two cryptographic modules, one on a computer one on a mobile phone, and the user wants to transport a key from the computer to the mobile phone. The user can export the key and related data in a standard format for input into the other cryptomodule.</t> </section> <section title="Transport of keys from Cryptomodule to Server"> <t>For example, a user wants to activate and use a new key and related data against a validation system that is not aware of this key. This key may be embedded in the cryptomodule (e.g. SD card, USB drive) that the user has purchased at the local electronics retailer. Along with the cryptomodule, the user may get the key on a CD or a floppy in a standard format. The user can now upload via a secure online channel or import this key and related data into the new validation system and start using the key.</t> </section> <section title="Server to server Bulk import/export of keys"> <t>From time to time, a key management system may be required to import or export keys in bulk from one entity to another. </t> <t>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.</t> <t>For example, in a variation of the above, an OTA key provisioning gateway that provisions keys to mobile phones may obtain key material from a key issuer using an online protocol. The keys are delivered in a standard format that can be processed by the key provisioning gateway and subsequently sent to the end-user's mobile phone.</t> </section> </section> <section title="Offline Use Cases"> <t>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. </t> <section title="Server to server Bulk import/export of keys"> <t>For example, cryptomodules such as OTP authentication tokens, may have their symmetric keys initialized during the manufacturing process in bulk, requiring copies of the keys and algorithm data to be loaded into the authentication system through a file on portable media. The manufacturer provides the keys and related data in the form of a file containing records in standard format, typically on a CD. Note that the token manufacturer and the vendor for the validation system may be the same or different. Some crypto modules will allow local PIN management (the device will have a PIN pad) hence random initial PINs set at manufacturing should be transmitted together with the respective keys they protect.</t> <t>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. </t> </section> </section> </section> <section title="Requirements"> <t>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. <list style="format R%d:"> <t>The format MUST support transport of multiple types of symmetric keys and related attributes for algorithms including HOTP, other OTP, challenge-response, etc.</t> <t>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 <list style="symbols"> <t>Unique Key Identifier</t> <t>Issuer information</t> <t>Algorithm ID</t> <t>Algorithm mode</t> <t>Issuer Name</t> <t>Key friendly name</t> <t>Event counter value (moving factor for OTP algorithms)</t> <t>Time value</t> </list> </t> <t>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 <xref target="DSKPP"/></t> <t>The format SHOULD allow bulk representation of symmetric keys</t> <t>The format SHOULD allow bulk representation of PINs related to specific keys</t> <t>The format SHOULD be portable to various platforms. Furthermore, it SHOULD be computationally efficient to process.</t> <t>The format MUST provide appropriate level of security in terms of data encryption and data integrity. </t> <t>For online scenarios the format SHOULD NOT rely on transport level security (e.g., SSL/TLS) for core security requirements.</t> <t>The format SHOULD be extensible. It SHOULD enable extension points allowing vendors to specify additional attributes in the future.</t> <t>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.</t> <t>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.</t> <t>The format MUST support the use of pre-shared symmetric keys to ensure confidentiality of sensitive data elements. </t> <t>The format MUST support a password-based encryption (PBE) <xref target="PKCS5"/> scheme to ensure security of sensitive data elements. This is a widely used method for various provisioning scenarios.</t> <t>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 encryption key is difficult to use. </t> </list> </t> </section> <section title="Portable Key container definition"> <t>The portable key container is based on an XML schema definition and contains the following main entities: <list style="numbers"> <t>KeyContainer entity as defined in <xref target="KeyContainerEntity"/> </t> <t>KeyProperties entity as defined in <xref target="KeyPropertiesEntity"/> </t> <t>Device entity as defined in <xref target="DeviceEntity"/> </t> <t>Key entity as defined in <xref target="KeyEntity"/> </t> </list> </t> <t>Additionally other XML schema types have been defined and are detailed in the relevant subsections of this document</t> <t>A KeyContainer MAY contain one or more Device entities. A Device MAY contain one or more Key entities</t> <t> The figure below indicates a possible relationship diagram of a container. </t> <figure> <artwork> -------------------------------------------- | KeyContainer | | | | -------------------- | | | Keyproperties 1 | | | | | | | -------------------- | | ------------------ ----------------- | | | Device 1 | | Device n | | | | | | | | | | ------------ | | ------------ | | | | | Key 1 | | | | Key n | | | | | ------------ | | ------------ | | | | | | | | | | | | | | | | ------------ | | ------------ | | | | | Key m | | | | Key p | | | | | ------------ | | ------------ | | | ------------------ ----------------- | | | -------------------------------------------- </artwork> </figure> <t>The following sections describe in detail all the entities and related XML schema elements and attributes:</t> <section anchor="KeyContainerEntity" title="KeyContainer"> <t>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.</t> <t>The KeyContainer is defined as follows:</t> <figure> <preamble/> <artwork><![CDATA[ <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" 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 name="ID" type="xs:ID" use="optional"/> </xs:complexType> ]]></artwork> <postamble/> </figure> <t>The attributes of the KeyContainer have the following meanings: <list style="symbols"> <t>Version (MANDATORY), the version number for the portable key container format (the XML schema defined in this document).</t> <t>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.</t> </list> </t> <t>The elements of the KeyContainer have the following meanings: <list style="symbols"> <t><EncryptionKey (OPTIONAL)>, Identifies the encryption key, algorithm and possible parameters used to protect the Secret Key data in the container. Please see <xref target="EncryptionKeyDescription"/> for detailed description of how to protect key data in transit and the usage of this element. </t> <t><MACAlgorithm (OPTIONAL)>, Identifies the algorithm used to generate a keyed digest 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 <xref target="SymmetricKeyProtectionDescription"/> </t> <t><KeyProperties (OPTIONAL)>, one or more key property entities containing key related properties that are common for keys within this container. Please see <xref target="KeyPropertiesEntity"/> for detailed description of this element. </t> <t><Device>, the host Device for one or more Keys as defined in <xref target="DeviceEntity"/> The KeyContainer MAY contain multiple Device data elements, allowing for bulk provisioning of multiple devices each containing multiple keys.</t> <t><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 <xref target="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.</t> <t><Extensions>, is the extension point for this entity. All extensions are grouped under this element and will be of type pskc:ExtensionsType, 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: <figure> <preamble/> <artwork><![CDATA[ <Extensions> <MyExtension1 definition="http://ACME/MyExtension1.html";>blah</Myextension1> <YourExtension99>blahblah</YourExtension99> </Extensions>]]></artwork> <postamble/> </figure> </t> </list> </t> </section> <section anchor="KeyPropertiesEntity" title="KeyProperties"> <t>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 KeyPropertiesId attribute. Values that are present in the Key element itself MUST take precedence over values set in KeyProperties. The KeyProperties is defined as follows:</t> <figure> <preamble/> <artwork><![CDATA[ <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 name="KeyPropertiesId" type="xs:ID" use="required"/> <xs:attribute name="KeyAlgorithm" type="pskc:KeyAlgorithmType" use="optional"/> </xs:complexType> ]]></artwork> <postamble/> </figure> <t>The attributes of the KeyProperties entity have the following meanings: <list style="symbols"> <t>KeyPropertiesId (MANDATORY), a unique and global identifier of set of KeyProperties. The identifier is defined as a string of alphanumeric characters.</t> <t>KeyAlgorithm (OPTIONAL), the unique URI of the type of algorithm to use with the secret key, for profiles are described in <xref target="KeyAlgorithmAttribute"/> </t> </list> </t> <t>Since KeyProperties are a method to commonalise the elements in Key please refer to <xref target="KeyEntity"/> for detailed description of all elements. </t> </section> <section anchor="DeviceEntity" title="Device"> <t>The Device represents an extensible Device entity in the Container. A Device MAY be bound to a user and MAY contain more than one keys. A key SHOULD be bound to only one Device.</t> <t>The Device is defined as follows:</t> <figure> <preamble/> <artwork><![CDATA[ <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="UserId" type="xs:string" minOccurs="0"/> <xs:element name="Extensions" type="pskc:ExtensionsType" minOccurs="0" maxOccurs="unbounded"/> </xs:sequence> </xs:complexType> ]]></artwork> <postamble/> </figure> <t>The elements of the Device have the following meanings: <list style="symbols"> <t><DeviceInfo>, a set of elements containing information about the device, whose values uniquely identify the device, defined in <xref target="DeviceInfoElement"/> </t> <t><Key>, represents the key entity as defined in <xref target="KeyEntity"/> </t> <t><UserId>, optionally identifies the owner or the user of the Device, a string representation of a Distinguished Name as defined in <xref target="RFC4514"/>. For example UID=jsmith,DC=example,DC=net. In systems where unique user Ids are used the string representation 'UID=[uniqueId]' MUST be used.</t> <t><Extensions>, is the extension point for this entity. All extensions are grouped under this element and will be of type pskc:ExtensionsType, 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: <figure> <preamble/> <artwork><![CDATA[ <Extensions> <MyExtension1 definition="http://ACME/MyExtension1.html";>blah</Myextension1> <YourExtension99>blahblah</YourExtension99> </Extensions>]]></artwork> <postamble/> </figure> </t> </list> </t> <section anchor="DeviceInfoElement" title="DeviceInfo"> <t>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.</t> <t>The DeviceInfo is defined as follows:</t> <figure> <preamble/> <artwork><![CDATA[ <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="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> ]]></artwork> <postamble/> </figure> <t>The elements of DeviceInfo have the following meanings: <list style="symbols"> <t><Manufacturer (MANDATORY)>, the manufacturer of the device.</t> <t><SerialNo (MANDATORY)>, the serial number of the device or the PAN (primary account number) in case of payment smart cards.</t> <t><Model (OPTIONAL)>, the model of the device (e.g. one-button-HOTP-token-V1)</t> <t><IssueNo (OPTIONAL)>, the issue number in case of smart cards with the same PAN, equivalent to a PSN (PAN Sequence Number).</t> <t><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.</t> <t><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. </t> <t><Extensions>, is the extension point for this entity. All extensions are grouped under this element and will be of type pskc:ExtensionsType, 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: <figure> <preamble/> <artwork><![CDATA[ <Extensions> <MyExtension1 definition="http://ACME/MyExtension1.html";>blah</Myextension1> <YourExtension99>blahblah</YourExtension99> </Extensions>]]></artwork> <postamble/> </figure> </t> </list> </t> </section> </section> <section anchor="KeyEntity" title="Key"> <t>The Key represents the key entity in the KeyContainer. The Key is defined as follows:</t> <figure> <preamble/> <artwork><![CDATA[ <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="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> ]]></artwork> <postamble/> </figure> <t>The attributes of the Key entity have the following meanings: <list style="symbols"> <t>KeyId (MANDATORY), a unique and global identifier of the symmetric key. The identifier is defined as a string of alphanumeric characters.</t> <t>KeyAlgorithm (OPTIONAL), the unique URI of the type of algorithm to use with the secret key, for profiles are described in <xref target="KeyAlgorithmAttribute"/> </t> <t>KeyProperties (OPTIONAL), the references to the unique id of the KeyProperties whose value the instance of this key inherits. If 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."/> </t> </list> </t> <t>The elements of the Key entity have the following meanings: <list style="symbols"> <t><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.</t> <t><Usage (OPTIONAL)>, defines the intended usage of the key and related metadata as defined in <xref target="UsageElement"/> </t> <t><KeyProfileId (OPTIONAL)>, A unique identifier used between the sending and receiving party of the container to establish a set of constant values related to a key that are not transmitted via the container. 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 could be an EMV MasterCard CAP <xref target="CAP"/> application on a card personalised with data for a specific batch of cards such as: <list style="hanging"> <t hangText="">IAF Internet authentication flag </t> <t hangText="">CVN Cryptogram version number, for example (MCHIP2, MCHIP4, VISA 13, VISA14)</t> <t hangText="">AIP (Application Interchange Profile), 2 bytes</t> <t hangText="">TVR Terminal Verification Result, 5 bytes</t> <t hangText="">CVR The card verification result</t> <t hangText="">AmountOther</t> <t hangText="">TransactionDate</t> <t hangText="">TerminalCountryCode</t> <t hangText="">TransactionCurrencyCode</t> <t hangText="">AmountAuthorised</t> <t hangText="">IIPB</t> </list> These values are not contained within attributes in the container but are shared between the manufacturing and the validation service through this unique KeyProfileId. The KeyProfileId is defined as a String.</t> <t><MasterKeyId (OPTIONAL)>, The unique reference to a 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.</t> <t><FriendlyName (OPTIONAL)>, The user friendly name that is assigned to the secret key for easy reference. The FriendlyName is defined as a String.</t> <t><Data (OPTIONAL)>, the element carrying the data related to the key as defined in <xref target="KeyDataElement"/> </t> <t><PINPolicy (OPTIONAL)>, the policy of the PIN relating to the usage of this key as defined in <xref target="PINPolicyElement"/> </t> <t><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.</t> <t><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.</t> <t><Extensions>, is the extension point for this entity. All extensions are grouped under this element and will be of type pskc:ExtensionsType, 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: <figure> <preamble/> <artwork><![CDATA[ <Extensions> <MyExtension1 definition="http://ACME/MyExtension1.html";>blah</Myextension1> <YourExtension99>blahblah</YourExtension99> </Extensions>]]></artwork> <postamble/> </figure> </t> </list> </t> <section anchor="KeyDataElement" title="KeyData (OPTIONAL)"> <t>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. The requirements were that the data elements could be encrypted but not via XML encryption which was deemed to complex because of canonicalization. Hence earlier drafts made use of a list of name value pairs. This was not considered to be very XML like and also lacked inbuilt support for typing. Hence the current apporach is to have within KeyData a set of elements that have both typing and can be encrypted. </t> <t>All elements within Data hence obey a simple structure in that they MUST have: <list style="hanging"> <t hangText="">A PlainValue Element that is typed to the specific type (e.g. xs:integer) </t> <t hangText="">An EncryptedValue element that is of type xenc:EncryptedDataType where the value of the specific element is placed in case it is encrypted</t> <t hangText="">A ValueMac element that is populated with a MAC in case the encryption algorithm does not support integrity checks</t> </list> </t> <t>For example the pskc:intDataType is defined as follows:</t> <figure> <preamble/> <artwork><![CDATA[ <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>]]></artwork> <postamble/> </figure> <t>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: <list style="hanging"> <t hangText="">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</t> <t hangText="">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</t> <t hangText="">pskc:binaryDataType - to carry data elements of type binary, PlainValue sub element is of type xs:Base64Binary</t> <t hangText="">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</t> </list> </t> <t>Therefore the KeyData element is defined as follows and contains sub ements to convey the values required by algorithms considered during the definition of this specification:</t> <figure> <preamble/> <artwork><![CDATA[ <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> ]]></artwork> <postamble/> </figure> <t>The elements of the Data element have the following meanings: <list style="symbols"> <t>The <Secret (OPTIONAL)> conveys the value of the key iself in binary.</t> <t>The <Counter (OPTIONAL)> the event counter for event based OTP algorithms.</t> <t>The <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)</t> <t>The <TimeInterval (OPTIONAL)> the time interval value for time based OTP algorithms.</t> <t>The <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. </t> <t>The <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.</t> </list> </t> </section> <section anchor="UsageElement" title="Usage (MANDATORY)"> <t>The Usage element defines the usage attribute(s) of the key entity. Usage is defined as follows:</t> <figure> <preamble/> <artwork><![CDATA[ <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> ]]></artwork> <postamble/> </figure> <t>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): <list style="symbols"> <t>OTP, the key will be used for OTP generation</t> <t>CR, the key will be used for Challenge/Response purposes</t> <t>Encrypt, the key will be used for data encryption purposes</t> <t>Integrity, the key will be used to generate a keyed message digest for data integrity or authentication purposes.</t> <t>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)</t> </list> </t> <t>The <Extensions> element, is the extension point for the Usage entity. All extensions are grouped under this element and will be of type pskc:ExtensionsType, 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: <figure> <preamble/> <artwork><![CDATA[ <Extensions> <MyExtension1 definition="http://ACME/MyExtension1.html";>blah</Myextension1> <YourExtension99>blahblah</YourExtension99> </Extensions>]]></artwork> <postamble/> </figure> </t> <section title="OTP and CR specific Usage elements (OPTIONAL)"> <t>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).</t> <section title="ChallengeFormat element (MANDATORY)"> <t>The ChallengeFormat element defines the characteristics of the challenge in a CR usage scenario. The Challenge element is defined by the following attributes: <list style="symbols"> <t>Format (MANDATORY) <list style="hanging"> <t hangText="">Defines the format of the challenge accepted by the device and MUST be one of the values defined in <xref target="ValueFormat"/> </t> </list> </t> <t>CheckDigit (OPTIONAL) <list style="hanging"> <t hangText="">Defines if the device needs to check the appended Luhn check digit contained in a provided challenge. This is only valid if the Format attribute is 'DECIMAL'. Value MUST be: <list style="hanging"> <t hangText="">TRUE device will check the appended Luhn check digit in a provided challenge </t> <t hangText="">FALSE device will not check appended Luhn check digit in challenge</t> </list> </t> </list> </t> <t>Min (MANDATORY) <list style="hanging"> <t hangText="">Defines the minimum size of the challenge accepted by the device for CR mode.</t>

Re: [KEYPROV] [pskc] Latest draft of PSKC - no more name value pairs