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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.