outer@utcsri.UUCP (Richard Outerbridge) (09/21/86)
Back in July there was a brief discussion of the DES IP and IP-1, to which I contributed my cynical belief that their only function was to confound software implementation of the DEA. Leafing through >Cryptography< by Meyer and Matyas last night, the following passage leaped out at me (I'd highlited it at some point) on page 116: "The initial and inverse permutations allow the algorithm to be implemented more easily on a single chip, provided that the data and the key are serially loaded." So: 'officially' they're there to make single chip (circa 1976) serially- loading hardware implementations easier. Is anyone familiar enough with the art of hardware (in 1976) and the DEA to opine whether or not this makes a whole lot of sense? Is that glass half-empty or half-full? -- Richard Outerbridge <outer@utcsri.UUCP> (416) 961-4757 Payload Deliveries: N 43 39'36", W 79 23'42", Elev. 106.47m.