Network Working Group Frank Dawson/Lotus Internet Draft Steve Mansour/Netscape <draft-ietf-calsch-imip-01.txt> Steve Silverberg/Microsoft Expires six months after September12, 1997 iCalendar Message-Based Interoperability Protocol (iMIP) Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, andits 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. Internet-Drafts may be updated, replaced, or made obsolete by other documents at any time. It is not appropriate to use Internet- Drafts as reference material or to cite them other than as a "working draft" or "work in progress". To learn the current status of any Internet-Draft, please check the 1id-abstracts.txt listing contained in the Internet-Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). Distribution of this document is unlimited. Abstract This document specifies a binding from the iCalendar Transport- independent Interoperability Protocol [ITIP] to Internet email-based transports. Calendaring entries defined by the iCalendar Object Model [ICAL] are composed using constructs from [RFC-822], [RFC-2045], [RFC-2046], [RFC-2047], [RFC-2048] and [RFC-2049]. This document is based on the calendaring and scheduling model defined by [ICMS]. This document is based on discussions within the Internet Engineering Task Force (IETF) Calendaring and Scheduling (CALSCH) working group. More information about the IETF CALSCH working group activities can be found on the IMC website at http://www.imc.org, the IETF website at http://www.ietf.org/html.charters/calsch-charter.html. Refer to the references within this document for further information on how to access these various documents. Distribution of this document is unlimited. Comments and suggestions for improvement should be sent to the authors. Dawson/Mansour/Silverberg 1 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 1 Introduction This binding document provides the transport specific information necessary convey iCalendar Transport-independent Interoperability Protocol [ITIP] over MIME as defined in [RFC-822] and [RFC-2045]. 1.1 Related Memos Implementors will need to be familar with several other memos that, along with this memo, form a framework for Internet calendaring and scheduling standards. This document - specifies an Internet email binding for [ITIP]. [ICMS] - specifies a common terminology and abstract; [ICAL] - specifies a core specification of objects, data types, properties and property parameters; [ITIP] - specifies an interoperability protocol for scheduling between different implementations; [IRIP] - specifies an Internet real time protocol binding for [ITIP]. This memo does not attempt to repeat the specification of concepts or definitions from these other memos. Where possible, references are made to the memo that provides for the specification of these concepts or definitions. 1.2 Formatting Conventions The mechanisms defined in this memo are defined in propose. In order to refer to elements of the calendaring and scheduling model, core object or interoperability protocol defined in [ICMS], [ICAL] and [ITIP] some formatting conventions have been used. Calendaring and scheduling roles defined by [ICMS] are referred to in quoted-strings of text with the first character of each word in upper case. For example, "Organizer" refers to a role of a "Calendar User" within the scheduling protocol defined by [ITIP] Calendar components defined by [ICAL] are referred to with capitalized, quoted-strings of text. All calendar components start with the letter "V". For example, "VEVENT" refers to the event calendar component, "VTODO" refers to the to-do calendar component and "VJOURNAL" refers to the daily journal calendar component. Scheduling methods defined by [ITIP] are referred to with capitalized, quoted-strings of text. For example, "REQUEST" refers to the method for requesting a scheduling calendar component be created or modified, "REPLY" refers to the method a recipient of a request uses to update their status with the "Organizer" of the calendar component. Dawson/Mansour/Silverberg 2 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 Properties defined by [ICAL] are referred to with capitalized, quoted-strings of text, followed by the word "property". For example, "ATTENDEE" property refers to the iCalendar property used to convey the calendar address of a calendar user. Property parameters defined by [ICAL] are referred to with lower case, quoted-strings of text, followed by the word "parameter". For example, "VALUE" parameter refers to the iCalendar property parameter used to override the default data type for a property value. 1.3 Terminology The email terms used in this memo are defined in [RFC-822] and [RFC- 2045]. The calendaring and scheduling terms used in this memo are defined in [ICMS], [ICAL] and [ITIP] 2 MIME Message Format Binding This section defines the message binding to the MIME electronic mail transport. The sections below refer to the "originator" and the "respondent" of an iMIP message. Typically, the originator is the owner or oganizer of an event. The respondent is an attendee of the event. In a well-organized email message the Reply-To header contains the email address of the originator or respondent of an event. However, this cannot be guaranteed as Mail User Agents (MUA) are not required to enforce iMIP semantics. 2.1 MIME Media Type A MIME entity containing content information formatted according to this design document will be referenced as a "text/calendar" content type. It is assumed that this content type will be transported through a MIME electronic mail transport. 2.2 Security This section addresses several aspects of security including Authentication, Authorization and Confidentiality. Authentication and confidentiality can be achieved using RFC 1847 which specifies the Security Multiparts for MIME. This framework defines new content types and subtypes of multipart: signed and encrypted. Each contains two body parts: one for the protected data and another for the control information necessary to remove the protection. 2.2.1 Authorization Per the [ICSM], only the organizer has authorization to modify or cancel calendar entries they organize. That is, spoof@xyz.com should not be able to modify or cancel a meeting that was organized by Dawson/Mansour/Silverberg 3 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 a@xyz.com. Furthermore, only the respondent has the authorization to indicate their status to the organizer. That is, spoof@xyz.com should not be able to tell the organizer that b@xyz.com declines a meeting invitation. [Editors note: this does not address issues around a calendar user assigning someone else as a delegate to accept or decline meetings on their behalf. For example, suppose an event invitation is sent to Joe (joe@x.com). Mary (mary@x.com), Joes administrative assistant, accepts the meeting on Joes behalf. How is this handled in the iTIP realm? Should the "From:" and/or "Reply-To" fields contain joe@x.com or mary@x.com? How is the organizer of the meeting to know that Mary can accept meetings on Joes behalf?] Hence, iMIP implementations must verify the authenticity of the sender of an iCalendar object before taking any action. This could be done by utilizing a Multipart/signed implementation of either PGP/MIME or S/MIME. [Editors note: this needs further clarification. How do you do this? The certificate owner must be somehow correlated to the organizer or the respondent. How is this done?] 2.2.2 Authentication Authentication can be performed using an implementation of RFC 1847 Multipart/signed that supports public/private key certificates. However, since most MUAs provide for the forwarding of messages, the organizer of an event and the sender of the message may be different. Therefore authentication may not be possible. 2.2.3 Confidentiality To ensure confidentiality using iMIP implementations should utilize RFC 1847 compliant encryption. The protocol does not restrict a CUA from forwarding Requests or Responses to other users or agents. 2.3 RFC 822 Addresses The calendar address specified within the "ATTENDEE" property in an iCalendar object MUST be a fully qualified, RFC 822 address for the corresponding "Owner", "Organizer" or "Attendee" of the "VEVENT" or "VTODO". The address MUST be the RFC 822 address for the calendaring and scheduling mailbox for the attendee. For purposes of authentication and authorization the RFC 822 "Sender" and "Reply-to" value MUST be the same as the address value for the "Organizer". Because [ITIP] does not preclude "Attendees" from forwarding "VEVENTS" or "VTODOS" to others, the RFC-822 "Sender" value may not equal that of the organizer. In these cases, authentication cannot be verified. Additionally, the "Organizer" cannot be inferred by the RFC-822 "Sender" or "Reply-to" values. Dawson/Mansour/Silverberg 4 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 Instead, it MUST be derived by opening the proper text/calendar MIME body part. 2.4 Content Type A MIME body part containing content information that conforms to this design document MUST have a Content-Type value of "text/calendar". The content type header field MUST also include the type parameter "method". The parameter value MUST be one of the message types defined by this method. The value MUST also be the same as the value of the METHOD calendar property within the iCalendar object. This means that if a MIME message containing multiple iCalendar objects with different method values, then they must be further encapsulated with a "multipart/mixed" MIME entity. This will allow each of the iCalendar objects to be encapsulated within their own "text/calendar" MIME entity. The Content-Type CHARSET parameter MUST appear in any MIME entity encapsulating an iCalendar object conforming to this design document. The CHARSET parameter value MUST be "UTF-8" or some other valid character set. The reason for this is that in [iCal] the default character set is UTF-8. The optional Content-Type COMPONENT parameter defines the iCalendar component type contained within the iCalendar object. The following is an example of this header field with a value that indicates an event request message. Content-Type:text/calendar; method=request; charset=UTF-8; component=vevent The "text/calendar" content type allows for the scheduling message type to be included in a MIME message with other content information (i.e., multipart/mixed) or included in a MIME message with a clear- text, human-readable form of the scheduling message (i.e., multipart/alternative). In order to permit the information in the scheduling message to be understood by MIME user agents (UA) that do not support the text/calendar content type, scheduling messages should be sent with an alternative, human-readable form of the information. 2.5 Content-Transfer-Encoding Note that the default character set for iCalendar objects is UTF-8 and a transfer encoding may be required. Content-Transfer-Encoding:quoted-printable 2.6 Content-Description The Content-Description header is optional. Dawson/Mansour/Silverberg 5 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 Content-Description: iCalendar REQUEST for an event 3 Examples In the examples below, the iCalendar object does not specify a character set, it is assumed to be UTF-8. Quoted-printable has been used to keep the message human readable. 3.1 Single Component With An ATTACH Property This minimal message shows a how a an iCalendar object references an attachment. The attachment is accessible by anyone via its URL. From: sman@netscape.com To: stevesil@microsoft.com Subject: Phone Conference Mime-Version: 1.0 Content-Type:text/calendar; method=REQUEST; charset=UTF-8 Content-Transfer-Encoding:quoted-printable BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:sman@netscape.com ATTENDEE;RSVP=YES;EXPECT=REQUEST:stevesil@microsoft.com DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Phone Conference DESCRIPTION:Please review the attached document. UID:www.acme.com-873970198738777 ATTACH:ftp://ftp.bar.com/pub/docs/foo.doc SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR 3.2 Single Component With An ATTACH Property and Inline Attachment This example shows how a message containing an iCalendar object references an attached document. The reference is made using a Content-id (CID). Thus, the iCalendar object and the document are packaged in a multipart/related encapsulation. From: foo1@bar.net To: foo2@bar.net Subject: Phone Conference Mime-Version: 1.0 Content-Type: multipart/related; boundary="boundary-example-1"; Dawson/Mansour/Silverberg 6 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 type=text/calendar --boundary-example-1 Content-Type:text/calendar; method=REQUEST; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net ATTENDEE;RSVP=YES;EXPECT=REQUEST; TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Phone Conference UID:www.acme.com-873970198738777 ATTACH:cid:www.acme.com-12345aaa SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR --boundary-example-1 Content-Type: application/msword; name="FieldReport.doc" Content-Transfer-Encoding: base64 Content-Disposition: inline; filename="FieldReport.doc" Content-ID: <www.acme.com-12345aaa> 0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAABAAAARAAAAAAA AAAAEAAAQAAAAAEAAAD+////AAAAAEUAAAD/////////////////////////////////e tc... --boundary-example-1-- 3.3 Multiple Similar Components Multiple iCalendar components can be included in the iCalendar object when the METHOD is the same for each component. From: foo1@bar.net To: foo2@bar.net Subject: Phone Conference Mime-Version: 1.0 Content-Type:text/calendar; method=REQUEST; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR Dawson/Mansour/Silverberg 7 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net ATTENDEE;RSVP=YES;EXPECT=REQUEST;TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Phone Conference DESCRIPTION:Discuss the contents of the attached document UID:www.acme.com-873970198738777 SEQUENCE:0 STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net ATTENDEE;RSVP=YES;EXPECT=REQUEST;TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970801T100000-0700 DTEND:19970801T103000-0700 SUMMARY:Follow-up Phone Conference DESCRIPTION:Discuss the contents of the attached document UID:www.acme.com-873970198738777 SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR 3.4 Multiple Mixed Components Different component types must be encapsulated in separate iCalendar objects. From: foo1@bar.net To: foo2@bar.net Subject: Phone Conference Mime-Version: 1.0 Content-Type:multipart/mixed;boundary="--FEE3790DC7E35189CA67CE2C" This is a multi-part message in MIME format. ----FEE3790DC7E35189CA67CE2C Content-Type:text/calendar; method=REQUEST; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net Dawson/Mansour/Silverberg 8 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 ATTENDEE;RSVP=YES;EXPECT=REQUEST;TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Phone Conference DESCRIPTION:Discuss the contents of the attached document UID:www.acme.com-873970198738777 SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR ----FEE3790DC7E35189CA67CE2C Content-Type:text/calendar; method=REQUEST; charset=UTF-8 Content-Transfer-Encoding:8bit Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VTODO DUE:19970701T090000-0700 SUMMARY:Phone Conference DESCRIPTION:Discuss the contents of the attached document UID:www.acme.com-td-873970198738777 SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR ----FEE3790DC7E35189CA67CE2C 3.5 Detailed Components With An ATTACH Property This example shows the format of a message containing a group meeting between three individuals. The multipart/related encapsulation is used because the iCalendar object contains an ATTACH property that uses a CID to reference the attachment. From: Steve Mansour <sman@netscape.com> MIME-Version: 1.0 To: Steve Silverberg <stevesil@exchange.microsoft.com>, Frank Dawson <fdawson@earthlink.net> Subject: REQUEST - Phone Conference Content-Type:multipart/mixed;boundary="--FEE3790DC7E35189CA67CE2C" This is a multi-part message in MIME format. ----FEE3790DC7E35189CA67CE2C Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Event REQUEST Dawson/Mansour/Silverberg 9 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 Decription: Lets discuss the attached document Begin: July 1, 1997 10:00 PDT End: July 1, 1997 10:30 PDT ----FEE3790DC7E35189CA67CE2C Content-Type: multipart/related; boundary="boundary-example-2"; type=text/calendar --boundary-example-2 Content-Type:text/calendar; method=REQUEST; charset=UTF-8; Component=vevent Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN PROFILE:REQUEST PROFILE-VERSION:1.0 VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net ATTENDEE;RSVP=YES;EXPECT=REQUEST;TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Lets discuss the attached document UID:www.acme.com-873970198738777 ATTACH:cid:www.acme.com-12345aaa SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR --boundary-example-2 Content-Type: application/msword; name="FieldReport.doc" Content-Transfer-Encoding: base64 Content-Disposition: inline; filename="FieldReport.doc" Content-ID: <www.acme.com-12345aaa> 0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAABAAAARAAAAAAA AAAAEAAAQAAAAAEAAAD+////AAAAAEUAAAD/////////////////////////////////e tc... --boundary-example-2-- ----FEE3790DC7E35189CA67CE2C-- Dawson/Mansour/Silverberg 10 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 4 Bibliography [ICAL] "Internet Calendaring and Scheduling Core Object Specification - iCalendar", Internet-Draft, July 1997, ftp://ftp.ietf.org/internet- drafts/draft-ietf-calsch-ical-02.txt. [ICMS] "Internet Calendaring Model Specification", Internet-Draft, July 1997, ftp://ftp.ietf.org/internet-drafts/draft-ietf-calsch-mod- 00.txt. [iTIP] This currently includes the following three documents that are being merged into a single iTIP document. 1. "iCalendar Transport-Independent Interoperability Protocol (iTIP) - Part 1: Scheduling Events and Busytime", Internet- Draft, July 1997, http://www.imc.org/draft-ietf-calsch-itip- part1-00.txt. 2. "iCalendar Transport-Independent Interoperability Protocol (iTIP) - Part 2: Scheduling To-dos", Internet-Draft, July 1997, http://www.imc.org/draft-ietf-calsch-itip-part2-00.txt 3. "iCalendar Transport-Independent Interoperability Protocol (iTIP) - Part 3: Scheduling Journal Entries", Internet-Draft, July 1997, http://www.imc.org/draft-ietf-calsch-itip-part3- 00.txt [ID-UTF8] "UTF-8, a transformation format of Unicode and ISO 10646", Internet-Draft, July,1996, ftp://ftp.ietf.org/internet-drafts/draft- yergeau-utf8-01.txt. [RFC-822] Crocker, D., "Standard for the Format of ARPA Internet Text Messages", STD 11, RFC 822, August 1982. [RFC-1847]. J. Galvin, S. Murphy, S. Crocker & N. Freed, "Security Multiparts for MIME: Multipart/Signed and Multipart/Encrypted", RFC 1847, October 1995. [RFC-2112] Levinson, E., "The MIME Multipart/Related Content-type," RFC 2112, March 1997. [RFC-2015] M. Elkins, "MIME Security with Pretty Good Privacy (PGP)," RFC 2015, October 1996. [RFC-2045] Freed, N., Borenstein, N., " Multipurpose Internet Mail Extensions (MIME) - Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [RFC-2046] Freed, N., Borenstein, N., " Multipurpose Internet Mail Extensions (MIME) - Part Two: Media Types", RFC 2046, November 1996. Dawson/Mansour/Silverberg 11 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 [RFC-2047] Moore, K., "Multipurpose Internet Mail Extensions (MIME) - Part Three: Message Header Extensions for Non-ASCII Text", RFC 2047, November 1996. [RFC-2048] Freed, N., J. Klensin, J. Postel, "Multipurpose Internet Mail Extensions (MIME) - Part Four: Registration Procedures", RFC 2048, January 1997. 5 Author's Address The following address information is provided in a vCard v2.1, Electronic Business Card, format. BEGIN:VCARD FN:Frank Dawson ORG:Lotus Development Corporation ADR;WORK;POSTAL;PARCEL:;;6544 Battleford Drive;Raleigh;NC;27613- 3502;USA TEL;WORK;MSG:+1-919-676-9515 TEL;WORK;FAX:+1-919-676-9564 EMAIL;INTERNET:fdawson@earthlink.net URL:http://home.earthlink.net/~fdawson END:VCARD BEGIN:VCARD FN:Steve Mansour ORG:Netscape Communications Corporation ADR;WORK;POSTAL;PARCEL:;;501 East Middlefield Road;Mountain View;CA;94043;USA TEL;WORK;MSG:+1-415-937-2378 TEL;WORK;FAX:+1-415-428-4059 EMAIL;INTERNET:sman@netscape.com END:VCARD BEGIN:VCARD FN:Steve Silverberg ORG:Microsoft Corporation ADR;WORK;POSTAL;PARCEL:;;One Microsoft Way; Redmond;WA;98052-6399;USA TEL;WORK;MSG:+1-206-936-9277 TEL;WORK;FAX:+1-206-936-8019 EMAIL;INTERNET:stevesil@Exchange.Microsoft.com END:VCARD The iCalendar Object is a result of the work of the Internet Engineering Task Force Calendaring and scheduling Working Group. The chairman of that working group is: BEGIN:VCARD FN:Anik Ganguly ORG:OnTime, Inc. ADR;WORK;POSTAL;PARCEL:10 Floor;;21700 Northwestern Highway;Southfield;MI;48075;USA Dawson/Mansour/Silverberg 12 Expires March 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) September 12, 1997 TEL;WORK;MSG:+1-810-559-5955 TEL;WORK;FAX:+1-810-559-5034 EMAIL;INTERNET:anik@ontime.com END:VCARD Dawson/Mansour/Silverberg 13 Expires March 1998
Datatracker
draft-ietf-calsch-imip-01
Internet-Draft
