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Re: Crypto algorithms for IKEv2



At 4:54 PM -0400 4/30/03, Paul Koning wrote:
>  >>>>> "Stephen" == Stephen Kent <kent@bbn.com> writes:
>
>  Stephen> At 1:17 PM -0400 4/29/03, Paul Koning wrote:
>  >> >>>>> "Michael" == Michael Richardson <mcr@sandelman.ottawa.on.ca>
>  >> writes:
>  >>
>  Michael> Editorial comments/questions:
>  >>
>  Michael> Where are the ENCR_DES_IV32 and ENCR_RC4 defined?
>  Michael> RFC2401bis?
>  >> Nowhere, I believe.
>  >>
>  >> ENCR_RC4 is clearly nonsense -- IPsec cannot work with stream
>  >> ciphers because IPsec works with IP datagrams.  Stream ciphers
>  >> like RC4 require loss-free delivery, which IP does not offer.  So
>  >> ENCR_RC4 is simply a mistake that was never corrected.
>  >>
>  >> paul
>
>  Stephen> I agree with the conclusion, but not the rationale.  One
>  Stephen> could use a stream cipher with IPsec, so long as one carries
>  Stephen> the state info needed for the cipher with each packet, just
>  Stephen> like we carry an IV.
>
>I suppose that is true, though handling out of order packets would be
>extremely painful.
>
>In any case, there is no "how to use RC4 with IPsec" RFC, and I
>suggest that no one should contemplate writing one.
>
>	paul
we are in agreement on that point.