8 .ds RF FORMFEED[Page %]
17 Network Working Group P. Riikonen
19 draft-riikonen-presence-attrs-00.txt XXX
25 User Online Presence and Information Attributes
26 <draft-riikonen-presence-attrs-00.txt>
31 This document is an Internet-Draft and is in full conformance with
32 all provisions of Section 10 of RFC 2026. Internet-Drafts are
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48 The distribution of this memo is unlimited.
54 This document defines set of attributes that can represent the online
55 user's presence in a network, and to provide general information about
56 the user. The purpose is to provide a generic mechanism to share
57 online presence and status, and general information about the user
58 to be used in several kind of network protocols and applications.
59 These attributes could be used by for example chat and conferencing
60 protocols (such as Instant Message protocols), network games, and
61 other similar network protocols and applications that has online
74 1 Introduction .................................................. 2
75 1.1 Requirements Terminology .................................. 2
76 2 Attributes Concept ............................................ 3
77 2.1 Requesting Attributes ..................................... 3
78 2.2 Replying Attributes ....................................... 3
79 2.3 Attribute Data Types ...................................... 4
80 2.4 Attribute Payload ......................................... 4
81 2.5 Attributes ................................................ 5
82 3 Security Considerations ....................................... 11
83 4 References .................................................... 12
84 5 Author's Address .............................................. 12
90 This document defines set of attributes that can represent the online
91 user's presence in a network, and to provide general information about
92 the user. The purpose is to provide a generic mechanism to share
93 online presence and status, and general information about the user
94 to be used in several kind of network protocols and applications.
95 These attributes could be used by for example chat and conferencing
96 protocols (such as Instant Message protocols), network games, and
97 other similar network protocols and applications that has online
100 This document does not define these attributes to be used in any
101 specific protocol, but assumes that they can be used generally in
102 any kind of online network protocol. Furthermore, the document
103 pays attention to special needs of various protocols, such as
104 mobile network protocols, which requires the attributes to be
105 both robust and compact. The attributes are also considered to be
106 easily implementable and for this reason a clear and robust structure
107 was chosen for the attributes.
109 This document is strongly influenced by Wireless Village Initiative
110 where similar attributes are defined, and credits for the ideas are
111 due there. However, they are defined only in the context of the
112 Wireless Village, and the format of the attributes used is not
113 suitable for general purpose usage.
117 1.1 Requirements Terminology
119 The keywords MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, RECOMMENDED,
120 MAY, and OPTIONAL, when they appear in this document, are to be
121 interpreted as described in [RFC2119].
127 Many network protocols needs a way to transfer and retrieve status
128 information about users in a network. For example, many chat and
129 conferencing protocols such as IRC, and all Instant Message (IM)
130 protocols, such as ICQ has a way to retrieve presence and status
131 information about the users in the network. This could be added to
132 several other kind of network protocols as well, and for this reason
133 a defined mechanism to provide these informations is needed.
135 The attributes are usually requested by an entity in the network
136 from other entity, usually a user or end user's device in the network.
137 The recipient then replies to each of the requested attributes and
138 sends the reply to the requester.
140 This document does not define the actual transport for requesting and
141 providing the replies to the requests, since this is irrelevant.
142 This document defines a payload for requesting, and providing the
143 information, but how the payload is transported is not defined in
144 this document. In a client-server network model the user requesting
145 attributes usually destine the request to a remote user and the
146 server relays the attributes to the remote user. It is also possible
147 that the concept is not user-to-user, but the server replies to the
148 requested attributes on behalf of the user.
152 2.1 Requesting Attributes
154 When an entity requests attributes from a user in the network,
155 it assembles a list of Attribute Payloads, and sets the requested
156 attribute value into the payload. Each requested attribute is a separate
157 Attribute Payload and they MUST be appended one after the other. The
158 requester need to understand that the recipient may not understand all
159 the requested attributes, and may not reply to all of the requested
160 attributes. The requester also need to understand that the recipient
161 may reply with additional attributes that were not requested.
165 2.2 Replying Attributes
167 When en entity receives the Attribute Payloads it parses them one after
168 the other. The entity can parse each of the Attribute Payload separately
169 since it knows the length of the current attribute; next attribute
170 begins after the current attribute ends. The entity then checks the
171 requested attribute and SHOULD reply either with valid value or with
172 an indication that the attribute is unsupported or unknown. It is
173 also possible to reply with additional attributes that were not
176 When replying to the requested attributes the entity assembles a list
177 of Attribute Payloads, each including the attribute type and the
178 actual attribute data.
182 2.3 Attribute Data Types
184 This section defines basic data types that can appear in the attributes
187 All integer values are stored in the MSB first order. The size of the
188 integer is provided separately with the attribute. Integer is
189 represented as "integer" in this documentation.
191 Strings are always UTF-8 [RFC2279] encoded, and include 2 bytes length
192 field indicating the length of the string. Hence, when "string" value
193 appears in this documentation it is encoded as:
197 2 bytes integer Length of String field
198 variable UTF-8 String
201 If string is not present then the length field includes zero (0)
204 Boolean value is represented as "boolean" and its size is 1 byte.
205 Value 0x00 indicates false value and value 0x01 indicates true value.
209 2.4 Attribute Payload
211 The Attribute Payload is used to request an attribute, and to reply
212 to the requested attribute. One payload includes one attribute.
218 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
219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
220 | Attribute | Attr Flags | Attribute Length |
221 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
229 Figure 1: Attribute Payload
233 o Attribute (1 byte) - Indicates the attribute included in this
236 o Attribute Flags (1 byte) - Indicates the flags associated
237 with this attribute. The following flags are defined:
239 0x01 ATTRIBUTE_FLAG_INVALID
241 The attribute value in Attribute Data is invalid, or
242 unknown. This may be set to indicate that a requested
243 attribute is not available, its value is unknown, or
244 sender does not understand it.
246 0x02 ATTRIBUTE_FLAG_VALID
248 The attribute value is included in the Attribute Data.
250 When sending this payload to request attributes this value
251 MUST be set to zero (0) value. When sending a reply to the
252 request this field MUST NOT include a zero (0) value.
254 o Attribute Length (2 bytes) - Indicates the length of the
255 Attribute Data field, not including any other field.
257 o Attribute Data (variable length) - The Attribute Data.
258 The contents of this field is attribute specific, defined
266 The following values can appear in the Attribute field in the
267 Attribute Payload to indicate the content of the attribute. The
268 format of the attribute data is represented as length, type and
273 2 bytes integer Some integer value
274 variable string Some string
275 1 byte boolean Boolean value
278 When sending multiple Attribute Payloads it is possible to include
279 multiple same attributes in the packet.
285 This attribute is reserved and it is never sent.
288 1 ATTRIBUTE_USER_INFO
290 This attribute includes general information about the user, their
291 name and contact information. The content of this attribute is
292 a VCard version 3.0 as defined in RFC 2426 [RFC2426] and RFC 2425
293 [RFC2425]. Note that some of the information that VCard provides
294 can be also provided in the means of providing other attributes.
295 The rationale for this is that the VCard does not provide all the
296 information, or with the required precision that may be desired in
297 some applications. It is therefore RECOMMENDED that this attribute
298 would be used to provide only basic and constant user information,
299 such as name and contact information, but not online status
303 variable VCard Basic user information
308 This attribute indicates a service in the Internet that the user
309 is currently using or has logged in. It also shows when the user
310 started using the service, and how long user has been idle in the
311 service. The value of this attribute is as follows:
314 4 bytes integer Service Port (IANA specified)
315 variable string Service Address
316 1 byte boolean Online status. If this is set to
317 0x01 (true) it means the user is online
318 in the service. Set to 0x00 (false) when
320 variable string Signon date and time, UTC date, format as
322 4 bytes integer Idle time
325 3 ATTRIBUTE_STATUS_MOOD
327 This attribute indicates the mood of the user. It can indicate
328 whether the user is eager to participate in the network. The
329 value of this attribute is as follows:
332 4 bytes integer Mood mask (values ORed together)
334 The following mood values are defined:
336 0x00000000 MOOD_NORMAL No specific mood, normal mood
337 0x00000001 MOOD_HAPPY The user feels happy
338 0x00000002 MOOD_SAD The user feels sad
339 0x00000004 MOOD_ANGRY The user feels angry
340 0x00000008 MOOD_JEALOUS The user feels jealous
341 0x00000010 MOOD_ASHAMED The user feels ashamed
342 0x00000020 MOOD_INVINCIBLE The user feels invincible
343 0x00000040 MOOD_INLOVE The user feels being in love
344 0x00000080 MOOD_SLEEPY The user feels sleepy
345 0x00000100 MOOD_BORED The user feels bored
346 0x00000200 MOOD_EXCITED The user feels excited
347 0x00000400 MOOD_ANXIOUS The user feels anxious
350 4 ATTRIBUTE_STATUS_FREETEXT
352 This attribute includes the user's online status free text. It
353 can provide personal status as a text message. The contents of
354 this attribute is a UTF-8 encoded free text string.
357 variable string Free text status string
360 5 ATTRIBUTE_STATUS_MESSAGE
362 This attribute includes the user's online status message. It
363 could provide for example a multi media message showing the status
364 of the user. The contents of this attribute is a MIME object,
365 which can be used to provide for example video, audio, image or
366 other similar status message. It could also provide a reference
367 to the message, for example an URL address.
370 variable MIME Status message as MIME object
373 6 ATTRIBUTE_PREFERRED_LANGUAGE
375 This attribute indicates the preferred language to be used when
376 communicating. The encoding of this attribute is as follows:
379 variable string ISO 639-2/T three letter code
382 7 ATTRIBUTE_PREFERRED_CONTACT
384 This attribute indicates the preferred contact methods. It can
385 indicate the method the user prefers when contacting. The value
386 of this attribute is as follows:
389 4 bytes integer Contact mask (values ORed together)
391 The following contact methods are defined:
393 0x00000000 CONTACT_NONE No specific preferred contact method
394 0x00000001 CONTACT_EMAIL Email is preferred
395 0x00000002 CONTACT_CALL Phone call is preferred
396 0x00000004 CONTACT_PAGE Paging is preferred
397 0x00000008 CONTACT_SMS SMS is preferred
398 0x00000010 CONTACT_MMS MMS is preferred
399 0x00000020 CONTACT_CHAT Chatting is preferred
404 This attribute can be used to provide the current local time for
405 the user. The contents of this attribute is a UTF-8 encoded
406 string and the format of the string is UTC time zone defined
410 variable string UTC date, format as in ISO 8601
412 Note that ATTRIBUTE_USER_INFO may also provide this information.
413 However it is RECOMMENDED that this attribute is used when
414 current time zone information is provided.
417 9 ATTRIBUTE_GEOLOCATION
419 This attribute can be used to provide measured global location of
420 the user. How this information is gathered is out of scope of
421 this document. The attribute can provide latitude and longitude
422 lateral positions, but also a vertical position. A parameter
423 describing the accuracy of the information can also be provided.
426 variable string Longitude
427 variable string Latitude
428 variable string Altitude
429 variable string Accuracy in meters
431 Note that ATTRIBUTE_USER_INFO may also provide this information,
432 however it does not have the vertical position, or the accuracy
433 parameter. It is RECOMMENDED that this attribute is used when
434 providing current global position information.
437 10 ATTRIBUTE_DEVICE_INFO
439 This attribute includes information about the user's device.
440 The encoding of this attribute is as follows:
443 4 bytes integer Device type
444 variable string Name of the device manufacturer
445 variable string Device version
446 variable string Device model
447 variable string Device language (ISO 639-2/T)
449 The following Device types are defined:
451 0 DEVICE_COMPUTER Device is a computer
452 1 DEVICE_MOBILE_PHONE Device is a mobile phone
453 2 DEVICE_PDA Device is a PDA
454 3 DEVICE_TERMINAL Device is a terminal
457 11 ATTRIBUTE_EXTENSION
459 This attribute indicates that the attribute value is vendor,
460 application or service specific attribute extension. This field
461 MUST include a MIME object, which is the extension value. This
462 document does not specify any explicit MIME objects for this
466 variable MIME Attribute extension as MIME object
469 12 ATTRIBUTE_USER_PUBLIC_KEY
471 This attribute includes the user's public key or certificate.
472 As the public key and certificate format depends on which sort
473 of algorithm or certificate encoding user is using we need to
474 define a mechanism to differentiate the public key types from
475 each other. This document specifies the most common public keys
476 and certificates. This attribute can be used to deliver the
477 user's public key, and it MUST be present if also the
478 ATTRIBUTE_USER_DIGITAL_SIGNATURE is present. Note that the
479 recipient of this attribute SHOULD verify the public key from
480 a third party, for example from Certification Authority. If
481 there are more than one ATTRIBUTE_USER_PUBLIC_KEY attributes set
482 and ATTRIBUTE_USER_DIGITAL_SIGNATURE is also set, the digital
483 signature SHOULD be verifiable with the first set public key.
486 variable string Public key/certificate type
487 variable data Public key/certificate data
489 The following public key/certificate types are defined:
491 ssh-rsa SSH RSA public key [SSH-TRANS]
492 ssh-dss SSH DSS public key [SSH-TRANS]
493 silc-rsa SILC RSA public key [SILC1]
494 silc-dss SILC DSS public key [SILC1]
495 pgp-sign-rsa OpenPGP RSA certificate [RFC2440]
496 pgp-sign-dss OpenPGP DSS certificate [RFC2440]
497 x509v3-sign-rsa X.509 Version 3 RSA certificate [RFC2459]
498 x509v3-sign-dss X.509 Version 3 DSS certificate [RFC2459]
500 Most of these public key/certificate types are equivalent to
501 the types specified for SSH protocol [SSH-TRANS] and are expected
502 to be officially assigned by IANA.
504 The encoding of the public key/certificate data in the attribute
505 is done in the manner defined in their respective definitions.
507 Note that these public keys are intended for signing. Some
508 certificates may have a key usage restrictions and same key cannot
509 be used for both encryption and signing. Therefore, the name
510 of the certificate type indicates if they are intended for
514 13 ATTRIBUTE_SERVER_PUBLIC_KEY
516 This attribute includes a third party server or authority public
517 key or CA certificate and MUST be present if the attribute
518 ATTRIBUTE_SERVER_DIGITAL_SIGNATURE is also present. The format
519 for this attribute is identical to the ATTRIBUTE_USER_PUBLIC_KEY
520 attribute. If there are more than one ATTRIBUTE_SERVER_PUBLIC_KEY
521 attributes set and ATTRIBUTE_SERVER_DIGITAL_SIGNATURE is also set,
522 the digital signature SHOULD be verifiable with the first set public
526 14 ATTRIBUTE_USER_DIGITAL_SIGNATURE
528 This attribute value includes digital signature of all Attribute
529 Payloads except this attribute. This signature can be provided by
530 the user. This attribute SHOULD be last attribute provided in the
531 reply so that it is easier for the receiver to compute the signature
532 data to be verified. The format and encoding of this attribute
533 depends on the public key or certificate used to produce the
534 signature. See the ATTRIBUTE_USER_PUBLIC_KEY for all public keys
535 and certificates that can be used to produce a signature.
538 variable data Digital signature data
540 The encodings are as follows per public key/certificate type:
542 ssh-rsa and ssh-dss Defined in [SSH-TRANS]
543 silc-rsa and silc-dss Defined in [SILC1]
544 pgp-sign-rsa and pgp-sign-dss Defined in [RFC2440]
545 x509v3-sign-rsa and x509v3-sign-dss Defined in [PKCS7]
547 The procedure producing the signature and encoding it are done
548 in the manner defined in their respective definitions, see the
549 provided references. Also the hash function used with the
550 signature procedure is defined by the public key/certificate type.
553 15 ATTRIBUTE_SERVER_DIGITAL_SIGNATURE
555 This attribute value includes digital signature of all Attribute
556 Payloads except this attribute, but including the attribute
557 ATTRIBUTE_USER_DIGITAL_SIGNATURE. This signature can be provided
558 by a third party server or an authority which has verified the
559 information provided by the user. How it verifies this information
560 is out of scope of this document, however it may base its
561 information to a previous registration information and current
562 online status of the user in a service. This attribute SHOULD be
563 last when provided, so that it is easier for the receiver to
564 compute the signature data to be verified. The format for this
565 attribute is identical to the ATTRIBUTE_USER_DIGITAL_SIGNATURE
571 3 Security Considerations
573 The use of these attributes dictates whether the attributes need to
574 be secured or not. However, as the attributes are considered to provide
575 accurate status information about specific user, it is suggested that
576 the attributes would be secured. The attributes should be digitally
577 signed whenever it is possible. Attributes can also be encrypted
578 if it is provided by the protocol using the attributes. A third party,
579 like a server in the network, could also verify the information and provide
580 digital signature in case the information is accurate.
582 Even though the attributes would be digitally signed by the sender of
583 the attributes, the information contained in the attribute may still
584 be incorrect. The third party server should not apply digital signature
585 unless it can verify every attribute. The receiver of the attributes
586 should also not trust that the information infact is correct.
588 However, it is possible that the context where these attributes are used
589 the attributes are provided by a party that can provide the accurate
590 information. For example a server in the network could reply to the
591 attributes on behalf of the actual user for some of the attributes.
597 [RFC2119] Bradner, S., "Key Words for use in RFCs to Indicate
598 Requirement Levels", BCP 14, RFC 2119, March 1997.
600 [RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO
601 10646", RFC 2279, January 1998.
603 [RFC2425] Howes, T., et al, "A MIME Content-Type for Directory
604 Information", RFC 2425, September 1998.
606 [RFC2426] Dawson, F., et al, "vCard MIME Directory Profile",
607 RFC 2426, September 1998.
609 [SILC1] Riikonen, P., "Secure Internet Live Conferencing (SILC),
610 Protocol Specification", Internet Draft, May 2002.
612 [RFC2440] Callas, J., et al, "OpenPGP Message Format", RFC 2440,
615 [RFC2459] Housley, R., et al, "Internet X.509 Public Key
616 Infrastructure, Certificate and CRL Profile", RFC 2459,
619 [SSH-TRANS] Ylonen, T., et al, "SSH Transport Layer Protocol",
622 [PKCS7] Kalinski, B., "PKCS #7: Cryptographic Message Syntax,
623 Version 1.5", RFC 2315, March 1998.
630 Snellmaninkatu 34 A 15
634 EMail: priikone@iki.fi
636 This Internet-Draft expires XXX