Re: Evaluation: draft-ietf-tsvwg-udp-lite - The UDP Lite Protocol to Proposed Standard

["Steven M. Bellovin" <smb@research.att.com>]

In message <200302141806.NAA29222@ietf.org>, IESG Secretary writes:
>
>Last Call to expire on: May 15, 2002
>
>	Please return the full line with your position.
>
>                    Yes    No-Objection  Discuss *  Abstain  
>
>
>Steve Bellovin      [   ]     [  ]       [ X ]      [   ] 

Some of the security considerations text isn't accurate.  The 
sentence starting "Many strong encryption transforms today exhibit this
behavior..." is just wrong -- the part of the sentence after the comma 
should be deleted.   For that matter, the word "strong" should go; even 
weak block ciphers, if used in CBC mode, have that property.  The following
sentence should be replaced by

   There exist encryption
   transforms, stream ciphers, which do not cause error propagation.

And the following text should be added:

	Note that omitting an integrity check can, under certain
	circumstances, compromise confidentiality [Bellovin98].

and probably this text, too:

	Pproper use of stream ciphers poses its own challenges [BB01].

Steven M. Bellovin, "Cryptography and the Internet", in Proceedings of
CRYPTO '98, August 1998. 

S. Bellovin and M. Blaze, "Cryptographic Modes of Operation for the
Internet", Second NIST Workshop on Modes of Operation, August 2001.

All of the above is intended as input for an RFC editor's note.


		--Steve Bellovin, http://www.research.att.com/~smb (me)
		http://www.wilyhacker.com (2nd edition of "Firewalls" book)