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RE: comments on draft-ietf-ipsec-ciph-cbc-02.txt



The draft <draft-ietf-ipsec-ciph-cbc-02.txt> does mention that IDEA
should use 8 rounds.  It does however mention 4 rounds, so we'll take
that out of the draft.


>-----Original Message-----
>From:	Markku-Juhani Saarinen [SMTP:mjos@ssh.fi]
>Sent:	Friday, March 13, 1998 3:27 AM
>To:	Roy Pereira
>Cc:	'ipsec@tis.com'
>Subject:	RE: comments on draft-ietf-ipsec-ciph-cbc-02.txt
>
>
>> How many rounds do you suggest for IDEA?
>
>IDEA has eight rounds.
>
>4-round IDEA is a research toy, and should not even be called IDEA.
>X. Lai and J. Massey never proposed it for real-life applications.
>
>It apparently creeped into the drafts because Applied Cryptography
>says (2nd ed, p. 325): 
>
>  "(..) Currently the best attack against IDEA is faster than brute force
>   only for 2.5 rounds or less; 4 round IDEA would be twice as fast and,
>   as far as I know, just as secure."
>
>This does not reflect our 1998 knowledge.
>
>- mj
>
>Markku-Juhani O. Saarinen <mjos@ssh.fi>, SSH Communications Security Ltd
>
>