Subject: I-D ACTION:draft-undery-sip-auth-01.txt

From: [email-masked]
Date: Mon, 17 Jun 2002 07:32:06 -0400

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title		: Enhanced Usage of HTTP Digest Authentication for SIP
	Author(s)	: J. Undery, S. Sen, V. Torvinen
	Filename	: draft-undery-sip-auth-01.txt
	Pages		: 7
	Date		: 14-Jun-02
	
HTTP Digest has some shortcomings if applied for SIP. Firstly, SIP 
UA has serious difficulties to distinguish the source of 
Authentication-Info and Proxy-Authentication-Info headers in SIP 
forking situations. This is due to the absence of the ærealmÆ 
parameter in these headers. Secondly, HTTP authentication is 
particularly vulnerable against MITM bid-down attacks on the list of 
algorithms (e.g., MD-5, SHA-1) or the desired security level (auth, 
auth-int). Thirdly, HTTP authentication provides limited integrity 
protection of only the message body. In SIP, important information 
can be carried in many of the headers that may need integrity 
protection. This draft proposes to add the realm parameter in the *-
Authentication-Info headers, recommends a format for computing the 
nonce for detection of bid-down attack and proposes a mechanism for 
integrity protection of SIP headers using MIME body.

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