Re: Crypto algorithms for IKEv2

[Paul Koning <pkoning@equallogic.com>]

>>>>> "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