Re: In practice they are a giant lookup table

Post #381,846 by a6l6e6x 10/9/13 9:15:18 AM Reply	Re: In practice they are a giant lookup table The look up table is not all that huge. I made DES hum on one of IBM's pieces of equipment, the 4700 bank branch controller. The look up table, which I implemented in assembly language gave it close to 7x performance boost compared to prior version. To be fair the processor was some 30% faster. Look up IBM Research's Lucifer project to see more on S-boxes. No connection to to 666! :) Alex
Post #381,848 by folkert 10/9/13 9:27:12 AM Reply	Worked with both... an S17A and S70. Forklift upgrade from the S17A to the S70. Both 32 Processor in one cabinet and 64GB of memory in two cabinets and a few cabinets of disk... a tape robot and cabinets of its media. Sheeit man. S70 took over an hour to start up, after a power transfer switch exploded and took all power out of the data center. The S70 had to do "checks"... Anyway... that thing just cranked. -- greg@gregfolkert.net "No snowflake in an avalanche ever feels responsible." --Stanislaw Jerzy Lec
Post #381,922 by static 10/9/13 10:12:38 PM Reply	No, it's not huge. But it's not small either. Not for the time. But I stand corrected about the prominence and providence of S-boxes. I must have been looking at leading edge encryption right at the point that researchers were abandoning the idea. :-) However, my point stands that the design characteristics of DES's S-boxes only started appearing long after DES was on the decline. I also note that DES was designed to be implemented in hardware. Software implementations really need a few CPU features that are not common for any sort of speed. Wade. Just Add Story http://justaddstory.wordpress.com/
Post #382,036 by a6l6e6x 10/11/13 6:44:59 PM Reply	Re: need a few CPU features that are not common Quite true. As is/was, the machine instructions are in a long sequence to get things done. And these are looped as well. Message encryption took milliseconds. Alex

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