pipenet

[Bill Ahern]

I am trying to build a prototype pipenet system. ver 1.1 of the model, as 
opposed to the original, calls for a MAC and sequence number. what are the 
implications of excluding the seperate MAC and simply using the sequence as 
the authenticator? since any decent cipher, using CBC mode, should alter the 
sequence regardless of its position in the cell. am i wrong on this? am i 
missing some relationship between a seperate MAC, a sequence and the cell?

if a seperate MAC is necessary, what are alternatives to using popular HMAC's 
(MD5,SHA1...), since these seem too long (16bytes * #nodes). would crc32 
suffice? 

thanx,

bill

p.s. feel free to shoot down any and all assumptions i have unwittingly made 
;)

-- 
Bill Ahern
wahern at 25thandClement.com

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