Subject: I-D ACTION:draft-ietf-sip-sec-agree-01.txt

From: [email-masked]
Date: Tue, 14 May 2002 08:01:41 -0400

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Session Initiation Protocol Working Group of the IETF.

	Title		: Security Mechanism Agreement for SIP Sessions
	Author(s)	: J. Arkko et al.
	Filename	: draft-ietf-sip-sec-agree-01.txt
	Pages		: 16
	Date		: 13-May-02
	
SIP has a number of security mechanisms. Some of them have been built
in to the SIP protocol, such as HTTP authentication or secure
attachments. These mechanisms have even alternative algorithms and
parameters. SIP does not currently provide any mechanism for
selecting which security mechanisms to use over a connection. In
particular, even if some mechanisms such as OPTIONS were used to make
this selection, the selection would be vulnerable against the
Bidding-Down attack. This document defines three header fields for
negotiating the security mechanisms within SIP between a user agent
client and its next hop SIP entity. A SIP entity applying this
mechanism must always require some minimum security (i.e. integrity
protection) from all communicating parties in order to secure the
negotiation, but the negotiation can agree on which specific minimum
security is used.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-sip-sec-agree-01.txt

To remove yourself from the IETF Announcement list, send a message to 
ietf-announce-request with the word unsubscribe in the body of the message.

Internet-Drafts are also available by anonymous FTP. Login with the username
"anonymous" and a password of your e-mail address. After logging in,
type "cd internet-drafts" and then
	"get draft-ietf-sip-sec-agree-01.txt".

A list of Internet-Drafts directories can be found in
http://www.ietf.org/shadow.html 
or ftp://ftp.ietf.org/ietf/1shadow-sites.txt

Internet-Drafts can also be obtained by e-mail.

Send a message to:
	[email-masked].
In the body type:
	"FILE /internet-drafts/draft-ietf-sip-sec-agree-01.txt".
	
NOTE:	The mail server at ietf.org can return the document in
	MIME-encoded form by using the "mpack" utility.  To use this
	feature, insert the command "ENCODING mime" before the "FILE"
	command.  To decode the response(s), you will need "munpack" or
	a MIME-compliant mail reader.  Different MIME-compliant mail readers
	exhibit different behavior, especially when dealing with
	"multipart" MIME messages (i.e. documents which have been split
	up into multiple messages), so check your local documentation on
	how to manipulate these messages.

Below is the data which will enable a MIME compliant mail reader
implementation to automatically retrieve the ASCII version of the
Internet-Draft.