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+Network Working Group P. Riikonen
+Internet-Draft
+draft-riikonen-presence-attrs-04.txt 15 January 2007
+Expires: 15 July 2007
+
+
+ User Online Presence and Information Attributes
+ <draft-riikonen-presence-attrs-04.txt>
+
+Status of this Draft
+
+ By submitting this Internet-Draft, each author represents that any
+ applicable patent or other IPR claims of which he or she is aware
+ have been or will be disclosed, and any of which he or she becomes
+ aware will be disclosed, in accordance with Section 6 of BCP 79.
+
+ Internet-Drafts are working documents of the Internet Engineering
+ Task Force (IETF), its areas, and its working groups. Note that
+ other groups may also distribute working documents as Internet-
+ Drafts. Internet-Drafts are draft documents valid for a maximum of
+ six months and may be updated, replaced, or obsoleted by other
+ documents at any time. It is inappropriate to use Internet-Drafts as
+ reference material or to cite them other than as "work in progress".
+
+ The list of current Internet-Drafts can be accessed at
+ http://www.ietf.org/1id-abstracts.html
+ The list of Internet-Draft Shadow Directories can be accessed at
+ http://www.ietf.org/shadow.html.
+
+
+
+Abstract
+
+ This document defines set of attributes that can represent the online
+ user's presence in a network, and to provide general information about
+ the user. The purpose is to provide a generic mechanism to share
+ online presence and status, and general information about the user
+ to be used in several kind of network protocols and applications.
+ These attributes could be used by for example chat and conferencing
+ protocols (such as Instant Message protocols), network games, and
+ other similar network protocols and applications that has online
+ users in a network.
+
+
+
+
+
+
+
+
+
+Riikonen [Page 1]
+\f
+Internet Draft 15 January 2007
+
+
+Table of Contents
+
+ 1 Introduction .................................................. 2
+ 1.1 Requirements Terminology .................................. 2
+ 2 Attributes Concept ............................................ 3
+ 2.1 Requesting Attributes ..................................... 3
+ 2.2 Replying Attributes ....................................... 3
+ 2.3 Attribute Data Types ...................................... 4
+ 2.4 Attribute Payload ......................................... 4
+ 2.5 Attributes ................................................ 5
+ 3 Security Considerations ....................................... 12
+ 4 References .................................................... 12
+ 5 Author's Address .............................................. 13
+ 6 Full Copyright Statement ...................................... 13
+
+
+1. Introduction
+
+ This document defines set of attributes that can represent the online
+ user's presence in a network, and to provide general information about
+ the user. The purpose is to provide a generic mechanism to share
+ online presence and status, and general information about the user
+ to be used in several kind of network protocols and applications.
+ These attributes could be used by for example chat and conferencing
+ protocols (such as Instant Message protocols), network games, and
+ other similar network protocols and applications that has online
+ users in a network.
+
+ This document does not define these attributes to be used in any
+ specific protocol, but assumes that they can be used generally in
+ any kind of online network protocol. Furthermore, the document
+ pays attention to special needs of various protocols, such as
+ mobile network protocols, which requires the attributes to be
+ both robust and compact. The attributes are also considered to be
+ easily implementable and for this reason a clear and robust structure
+ was chosen for the attributes.
+
+ This document is strongly influenced by Wireless Village Initiative
+ where similar attributes are defined, and credits for the ideas are
+ due there. However, they are defined only in the context of the
+ Wireless Village, and the format of the attributes used is not
+ suitable for general purpose usage.
+
+
+1.1 Requirements Terminology
+
+ The keywords MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, RECOMMENDED,
+ MAY, and OPTIONAL, when they appear in this document, are to be
+
+
+
+Riikonen [Page 2]
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+Internet Draft 15 January 2007
+
+
+ interpreted as described in [RFC2119].
+
+
+2 Attributes Concept
+
+ Many network protocols needs a way to transfer and retrieve status
+ information about users in a network. For example, many chat and
+ conferencing protocols such as IRC, and all Instant Message (IM)
+ protocols, such as ICQ has a way to retrieve presence and status
+ information about the users in the network. This could be added to
+ several other kind of network protocols as well, and for this reason
+ a defined mechanism to provide these informations is needed.
+
+ The attributes are usually requested by an entity in the network
+ from other entity, usually a user or end user's device in the network.
+ The recipient then replies to each of the requested attributes and
+ sends the reply to the requester.
+
+ This document does not define the actual transport for requesting and
+ providing the replies to the requests, since this is irrelevant.
+ This document defines a payload for requesting, and providing the
+ information, but how the payload is transported is not defined in
+ this document. In a client-server network model the user requesting
+ attributes usually destine the request to a remote user and the
+ server relays the attributes to the remote user. It is also possible
+ that the concept is not user-to-user, but the server replies to the
+ requested attributes on behalf of the user.
+
+
+2.1 Requesting Attributes
+
+ When an entity requests attributes from a user in the network,
+ it assembles a list of Attribute Payloads, and sets the requested
+ attribute value into the payload. Each requested attribute is a separate
+ Attribute Payload and they MUST be appended one after the other. The
+ requester need to understand that the recipient may not understand all
+ the requested attributes, and may not reply to all of the requested
+ attributes. The requester also need to understand that the recipient
+ may reply with additional attributes that were not requested.
+
+
+2.2 Replying Attributes
+
+ When en entity receives the Attribute Payloads it parses them one after
+ the other. The entity can parse each of the Attribute Payload separately
+ since it knows the length of the current attribute; next attribute
+ begins after the current attribute ends. The entity then checks the
+ requested attribute and SHOULD reply either with valid value or with
+
+
+
+Riikonen [Page 3]
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+Internet Draft 15 January 2007
+
+
+ an indication that the attribute is unsupported or unknown. It is
+ also possible to reply with additional attributes that were not
+ requested.
+
+ When replying to the requested attributes the entity assembles a list
+ of Attribute Payloads, each including the attribute type and the
+ actual attribute data.
+
+
+2.3 Attribute Data Types
+
+ This section defines basic data types that can appear in the attributes
+ in this document.
+
+ All integer values are stored in the MSB first order. The size of the
+ integer is provided separately with the attribute. Integer is
+ represented as "integer" in this documentation.
+
+ Strings MUST be UTF-8 [RFC2279] encoded, and include 2 bytes length
+ field indicating the length of the string. Hence, when "string" value
+ appears in this documentation it is encoded as:
+
+ Length Type Value
+ 2 bytes integer Length of String field
+ variable UTF-8 String
+
+ If string is not present then the length field includes zero (0)
+ value.
+
+ Boolean value is represented as "boolean" and its size is 1 byte.
+ Value 0x00 indicates false value and value 0x01 indicates true value.
+
+
+2.4 Attribute Payload
+
+ The Attribute Payload is used to request an attribute, and to reply
+ to the requested attribute. One payload includes one attribute.
+
+
+ 1 2 3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Attribute | Attr Flags | Attribute Length |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | |
+ ~ Attribute Data ~
+ | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+
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+Internet Draft 15 January 2007
+
+
+ Figure 1: Attribute Payload
+
+
+ o Attribute (1 byte) - Indicates the attribute included in this
+ Attribute Payload.
+
+ o Attribute Flags (1 byte) - Indicates the flags associated
+ with this attribute. The following flags are defined:
+
+ 0x01 ATTRIBUTE_FLAG_INVALID
+
+ The attribute value in Attribute Data is invalid, or
+ unknown. This may be set to indicate that a requested
+ attribute is not available, its value is unknown, or
+ sender does not understand it.
+
+ 0x02 ATTRIBUTE_FLAG_VALID
+
+ The attribute value is included in the Attribute Data.
+
+ When sending this payload to request attributes this value
+ MUST be set to zero (0) value. When sending a reply to the
+ request this field MUST NOT include a zero (0) value.
+
+ o Attribute Length (2 bytes) - Indicates the length of the
+ Attribute Data field, not including any other field.
+
+ o Attribute Data (variable length) - The Attribute Data.
+ The contents of this field is attribute specific, defined
+ subsequently.
+
+
+2.5 Attributes
+
+ The following values can appear in the Attribute field in the
+ Attribute Payload to indicate the content of the attribute. The
+ format of the attribute data is represented as length, type and
+ value. Example:
+
+ Length Type Value
+ 2 bytes integer Some integer value
+ variable string Some string
+ 1 byte boolean Boolean value
+
+ When sending multiple Attribute Payloads it is possible to include
+ multiple same attributes in the packet.
+
+
+
+
+
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+Internet Draft 15 January 2007
+
+
+ 0 ATTRIBUTE_NONE
+
+ This attribute is reserved and it is never sent.
+
+
+ 1 ATTRIBUTE_USER_INFO
+
+ This attribute includes general information about the user, their
+ name and contact information. The content of this attribute is
+ a VCard version 3.0 as defined in RFC 2426 [RFC2426] and RFC 2425
+ [RFC2425]. Note that some of the information that VCard provides
+ can be also provided in the means of providing other attributes.
+ The rationale for this is that the VCard does not provide all the
+ information, or with the required precision that may be desired in
+ some applications. It is therefore RECOMMENDED that this attribute
+ would be used to provide only basic and constant user information,
+ such as name and contact information, but not online status
+ information.
+
+ Length Type Value
+ variable VCard Basic user information
+
+
+ 2 ATTRIBUTE_SERVICE
+
+ This attribute indicates a service in the Internet that the user
+ is currently using or has logged in. It also shows when the user
+ started using the service, and how long user has been idle in the
+ service. The value of this attribute is as follows:
+
+ Length Type Value
+ 4 bytes integer Service Port (IANA specified)
+ variable string Service Address
+ 1 byte boolean Online status. If this is set to
+ 0x01 (true) it means the user is online
+ in the service. Set to 0x00 (false) when
+ out of reach.
+ variable string Signon date and time, UTC date, format as
+ in ISO 8601
+ 4 bytes integer Idle time
+
+
+ 3 ATTRIBUTE_STATUS_MOOD
+
+ This attribute indicates the mood of the user. It can indicate
+ whether the user is eager to participate in the network. The
+ value of this attribute is as follows:
+
+
+
+
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+Internet Draft 15 January 2007
+
+
+ Length Type Value
+ 4 bytes integer Mood mask (values ORed together)
+
+ The following mood values are defined:
+
+ 0x00000000 MOOD_NORMAL No specific mood, normal mood
+ 0x00000001 MOOD_HAPPY The user feels happy
+ 0x00000002 MOOD_SAD The user feels sad
+ 0x00000004 MOOD_ANGRY The user feels angry
+ 0x00000008 MOOD_JEALOUS The user feels jealous
+ 0x00000010 MOOD_ASHAMED The user feels ashamed
+ 0x00000020 MOOD_INVINCIBLE The user feels invincible
+ 0x00000040 MOOD_INLOVE The user feels being in love
+ 0x00000080 MOOD_SLEEPY The user feels sleepy
+ 0x00000100 MOOD_BORED The user feels bored
+ 0x00000200 MOOD_EXCITED The user feels excited
+ 0x00000400 MOOD_ANXIOUS The user feels anxious
+
+
+ 4 ATTRIBUTE_STATUS_FREETEXT
+
+ This attribute includes the user's online status free text. It
+ can provide personal status as a text message. The contents of
+ this attribute is a UTF-8 encoded free text string.
+
+ Length Type Value
+ variable string Free text status string
+
+
+ 5 ATTRIBUTE_STATUS_MESSAGE
+
+ This attribute includes the user's online status message. It
+ could provide for example a multi media message showing the status
+ of the user. The contents of this attribute is a MIME object,
+ which can be used to provide for example video, audio, image or
+ other similar status message. It could also provide a reference
+ to the message, for example an URL address.
+
+ Length Type Value
+ variable MIME Status message as MIME object
+
+
+ 6 ATTRIBUTE_PREFERRED_LANGUAGE
+
+ This attribute indicates the preferred language to be used when
+ communicating. The encoding of this attribute is as follows:
+
+ Length Type Value
+
+
+
+Riikonen [Page 7]
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+Internet Draft 15 January 2007
+
+
+ variable string ISO 639-2/T three letter code
+
+
+ 7 ATTRIBUTE_PREFERRED_CONTACT
+
+ This attribute indicates the preferred contact methods. It can
+ indicate the method the user prefers when contacting. The value
+ of this attribute is as follows:
+
+ Length Type Value
+ 4 bytes integer Contact mask (values ORed together)
+
+ The following contact methods are defined:
+
+ 0x00000000 CONTACT_NONE No specific preferred contact method
+ 0x00000001 CONTACT_EMAIL Email is preferred
+ 0x00000002 CONTACT_CALL Phone call is preferred
+ 0x00000004 CONTACT_PAGE Paging is preferred
+ 0x00000008 CONTACT_SMS SMS is preferred
+ 0x00000010 CONTACT_MMS MMS is preferred
+ 0x00000020 CONTACT_CHAT Chatting is preferred
+ 0x00000040 CONTACT_VIDEO Video conferencing is preferred
+
+
+ 8 ATTRIBUTE_TIMEZONE
+
+ This attribute can be used to provide the current local time for
+ the user. The contents of this attribute is a UTF-8 encoded
+ string and the format of the string is UTC time zone defined
+ in the ISO 8601.
+
+ Length Type Value
+ variable string UTC date, format as in ISO 8601
+
+ Note that ATTRIBUTE_USER_INFO may also provide this information.
+ However it is RECOMMENDED that this attribute is used when
+ current time zone information is provided.
+
+
+ 9 ATTRIBUTE_GEOLOCATION
+
+ This attribute can be used to provide measured global location of
+ the user. How this information is gathered is out of scope of
+ this document. The attribute can provide latitude and longitude
+ lateral positions, but also a vertical position. A parameter
+ describing the accuracy of the information can also be provided.
+
+ Length Type Value
+
+
+
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+Internet Draft 15 January 2007
+
+
+ variable string Longitude (ex. 31 17 14.321W)
+ variable string Latitude (ex. 12 11 21.2N)
+ variable string Altitude
+ variable string Accuracy in meters
+
+ Note that ATTRIBUTE_USER_INFO may also provide this information,
+ however it does not have the vertical position, or the accuracy
+ parameter. It is RECOMMENDED that this attribute is used when
+ providing current global position information.
+
+
+ 10 ATTRIBUTE_DEVICE_INFO
+
+ This attribute includes information about the user's device.
+ The encoding of this attribute is as follows:
+
+ Length Type Value
+ 4 bytes integer Device type
+ variable string Name of the device manufacturer
+ variable string Device version
+ variable string Device model
+ variable string Device language (ISO 639-2/T)
+
+ The following Device types are defined:
+
+ 0 DEVICE_COMPUTER Device is a computer
+ 1 DEVICE_MOBILE_PHONE Device is a mobile phone
+ 2 DEVICE_PDA Device is a PDA
+ 3 DEVICE_TERMINAL Device is a terminal
+
+
+ 11 ATTRIBUTE_EXTENSION
+
+ This attribute indicates that the attribute value is vendor,
+ application or service specific attribute extension. This field
+ MUST include a MIME object, which is the extension value. This
+ document does not specify any explicit MIME objects for this
+ attribute.
+
+ Length Type Value
+ variable MIME Attribute extension as MIME object
+
+
+ 12 ATTRIBUTE_USER_PUBLIC_KEY
+
+ This attribute includes the user's public key or certificate.
+ As the public key and certificate format depends on which sort
+ of algorithm or certificate encoding user is using we need to
+
+
+
+Riikonen [Page 9]
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+Internet Draft 15 January 2007
+
+
+ define a mechanism to differentiate the public key types from
+ each other. This document specifies the most common public keys
+ and certificates. This attribute can be used to deliver the
+ user's public key, and it MUST be present if also the
+ ATTRIBUTE_USER_DIGITAL_SIGNATURE is present. Note that the
+ recipient of this attribute SHOULD verify the public key from
+ a third party, for example from Certification Authority. If
+ there are more than one ATTRIBUTE_USER_PUBLIC_KEY attributes set
+ and ATTRIBUTE_USER_DIGITAL_SIGNATURE is also set, the digital
+ signature SHOULD be verifiable with the first set public key.
+
+ Length Type Value
+ variable string Public key/certificate type
+ variable data Public key/certificate data
+
+ The following public key/certificate types are defined:
+
+ ssh-rsa SSH RSA public key [SSH-TRANS]
+ ssh-dss SSH DSS public key [SSH-TRANS]
+ silc-rsa SILC RSA public key [SILC1]
+ silc-dss SILC DSS public key [SILC1]
+ pgp-sign-rsa OpenPGP RSA certificate [RFC2440]
+ pgp-sign-dss OpenPGP DSS certificate [RFC2440]
+ x509v3-sign-rsa X.509 Version 3 RSA certificate [RFC2459]
+ x509v3-sign-dss X.509 Version 3 DSS certificate [RFC2459]
+
+ Most of these public key/certificate types are equivalent to
+ the types specified for SSH protocol [SSH-TRANS] and are expected
+ to be officially assigned by IANA.
+
+ The encoding of the public key/certificate data in the attribute
+ is done in the manner defined in their respective definitions.
+
+ Note that these public keys are intended for signing. Some
+ certificates may have a key usage restrictions and same key cannot
+ be used for both encryption and signing. Therefore, the name
+ of the certificate type indicates if they are intended for
+ signing only.
+
+
+ 13 ATTRIBUTE_SERVER_PUBLIC_KEY
+
+ This attribute includes a third party server or authority public
+ key or CA certificate and MUST be present if the attribute
+ ATTRIBUTE_SERVER_DIGITAL_SIGNATURE is also present. The format
+ for this attribute is identical to the ATTRIBUTE_USER_PUBLIC_KEY
+ attribute. If there are more than one ATTRIBUTE_SERVER_PUBLIC_KEY
+ attributes set and ATTRIBUTE_SERVER_DIGITAL_SIGNATURE is also set,
+
+
+
+Riikonen [Page 10]
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+Internet Draft 15 January 2007
+
+
+ the digital signature SHOULD be verifiable with the first set public
+ key.
+
+
+ 14 ATTRIBUTE_USER_DIGITAL_SIGNATURE
+
+ This attribute value includes digital signature of all Attribute
+ Payloads except this attribute. This signature can be provided by
+ the user. This attribute SHOULD be last attribute provided in the
+ reply so that it is easier for the receiver to compute the signature
+ data to be verified. The format and encoding of this attribute
+ depends on the public key or certificate used to produce the
+ signature. See the ATTRIBUTE_USER_PUBLIC_KEY for all public keys
+ and certificates that can be used to produce a signature.
+
+ Length Type Value
+ variable data Digital signature data
+
+ The encodings are as follows per public key/certificate type:
+
+ ssh-rsa and ssh-dss Defined in [SSH-TRANS]
+ silc-rsa and silc-dss Defined in [SILC1]
+ pgp-sign-rsa and pgp-sign-dss Defined in [RFC2440]
+ x509v3-sign-rsa and x509v3-sign-dss Defined in [PKCS7]
+
+ The procedure producing the signature and encoding it are done
+ in the manner defined in their respective definitions, see the
+ provided references. Also the hash function used with the
+ signature procedure is defined by the public key/certificate type.
+
+
+ 15 ATTRIBUTE_SERVER_DIGITAL_SIGNATURE
+
+ This attribute value includes digital signature of all Attribute
+ Payloads except this attribute, but including the attribute
+ ATTRIBUTE_USER_DIGITAL_SIGNATURE. This signature can be provided
+ by a third party server or an authority which has verified the
+ information provided by the user. How it verifies this information
+ is out of scope of this document, however it may base its
+ information to a previous registration information and current
+ online status of the user in a service. This attribute SHOULD be
+ last when provided, so that it is easier for the receiver to
+ compute the signature data to be verified. The format for this
+ attribute is identical to the ATTRIBUTE_USER_DIGITAL_SIGNATURE
+ attribute.
+
+
+ 16 ATTRIBUTE_USER_ICON
+
+
+
+Riikonen [Page 11]
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+Internet Draft 15 January 2007
+
+
+ This attribute includes the user's icon or picture that can be
+ associated with the user in the application's user interface.
+ The attribute is a MIME object of which content MUST be one of
+ the MIME image media types.
+
+ Length Type Value
+ variable MIME Icon as MIME image message
+
+
+3 Security Considerations
+
+ The use of these attributes dictates whether the attributes need to
+ be secured or not. However, as the attributes are considered to provide
+ accurate status information about specific user, it is suggested that
+ the attributes would be secured. The attributes should be digitally
+ signed whenever it is possible. Attributes can also be encrypted
+ if it is provided by the protocol using the attributes. A third party,
+ like a server in the network, could also verify the information and provide
+ digital signature in case the information is accurate.
+
+ Even though the attributes would be digitally signed by the sender of
+ the attributes, the information contained in the attribute may still
+ be incorrect. The third party server should not apply digital signature
+ unless it can verify every attribute. The receiver of the attributes
+ should also not trust that the information in fact is correct.
+
+ However, it is possible that the context where these attributes are used
+ the attributes are provided by a party that can provide the accurate
+ information. For example a server in the network could reply to the
+ attributes on behalf of the actual user for some of the attributes.
+
+
+4 References
+
+ [RFC2119] Bradner, S., "Key Words for use in RFCs to Indicate
+ Requirement Levels", BCP 14, RFC 2119, March 1997.
+
+ [RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO
+ 10646", RFC 2279, January 1998.
+
+ [RFC2425] Howes, T., et al, "A MIME Content-Type for Directory
+ Information", RFC 2425, September 1998.
+
+ [RFC2426] Dawson, F., et al, "vCard MIME Directory Profile",
+ RFC 2426, September 1998.
+
+ [SILC1] Riikonen, P., "Secure Internet Live Conferencing (SILC),
+ Protocol Specification", Internet Draft, January 2007.
+
+
+
+Riikonen [Page 12]
+\f
+Internet Draft 15 January 2007
+
+
+ [RFC2440] Callas, J., et al, "OpenPGP Message Format", RFC 2440,
+ November 1998.
+
+ [RFC2459] Housley, R., et al, "Internet X.509 Public Key
+ Infrastructure, Certificate and CRL Profile", RFC 2459,
+ January 1999.
+
+ [SSH-TRANS] Ylonen, T., et al, "SSH Transport Layer Protocol",
+ Internet Draft.
+
+ [PKCS7] Kalinski, B., "PKCS #7: Cryptographic Message Syntax,
+ Version 1.5", RFC 2315, March 1998.
+
+
+
+
+5 Author's Address
+
+ Pekka Riikonen
+ Helsinki
+ Finland
+
+ EMail: priikone@iki.fi
+
+
+6 Full Copyright Statement
+
+ Copyright (C) The Internet Society (2007).
+
+ This document is subject to the rights, licenses and restrictions
+ contained in BCP 78, and except as set forth therein, the authors
+ retain all their rights.
+
+ This document and the information contained herein are provided on an
+ "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
+ OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
+ ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
+ INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
+ INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
+ WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+
+
+
+
+
+
+
+
+
+
+Riikonen [Page 13]
+\f
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