Jesús Cea Avión wrote:
In the Rivest's paper you transmit, indeed, all the 2^n plaintexts for a n bit length };-).
Not so. In his paper (before the package tranform stuff), he had the following expansion. Assuming a 32 bit serial number and a 160 bit MAC, n bits would expand to 388n. This is because Ron is sending it out like this: quote from http://theory.lcs.mit.edu/~rivest/chaffing.txt
To make this clearer with an example, note that the adversary will see triples of the form: (1,0,351216) (1,1,895634) (2,0,452412) (2,1,534981) (3,0,639723) (3,1,905344) (4,0,321329) (4,1,978823) ... and so on.
Every bit is getting 2 32-bit serial numbers, its own complement, and 2 160-bit MACs. a 10KB file would explode into a 3.789MB file. Not too practical, eh? :-) -- o Mordy Ovits o Programmer / Cryptographer o SynData Technologies Inc. o Download A Free Copy Of Our Software At: o http://www.syncrypt.com