Re: "S1" encryption system
Correction, I just noticed that the four F functions have 4 bit output not 8 as I wrote. Realize that all this is based on a very cursory examination of the code. BTW I just was starting to look at the key scheduling and I noticed that fullkey is indexed in its 2nd slot by i*2 where i goes from 0 to 31, but is only declared as being 32 in size in that slot. So I think this is another typo, probably the index should be i. This kind of thing does not inspire confidence... Hal
-----BEGIN PGP SIGNED MESSAGE----- BTW, I compiled it and confirmed that decryption is the inverse of encryption for at least one (key, plaintext) pair..
BTW I just was starting to look at the key scheduling and I noticed that fullkey is indexed in its 2nd slot by i*2 where i goes from 0 to 31, but is only declared as being 32 in size in that slot. So I think this is another typo, probably the index should be i. This kind of thing does not inspire confidence...
It looks very much like the sort of typo you would get from a mistranslation from assembly language if the target architecture had a *4-bit* processor. (This is also consistant with the "<<4"'s which show up in several places in the code). The typo is consistant -- it shows up every time the key schedule is referenced; it looks like a semi-mechanical translation was done.. - Bill -----BEGIN PGP SIGNATURE----- Version: 2.6.1 iQCVAwUBMCmOdbT+rHlVUGpxAQFdNQP+I5lvR0itV0l2ypGF7EGGKrYcTnSNa0Fn UqD7IIQ/BqViSeoXFHWzWJ5KUj9+y9RuKmwnMGGrlxRunZSDUya4VX0PZOX0bP4K rbtu2j2H33cIrDPA+POvVYNAXBj3Sw1paIVf/07937oDZfdsqrn8c4rgXEeMgk4U aoH4lpMfxY8= =dd0O -----END PGP SIGNATURE-----
On Thu, 10 Aug 1995, Bill Sommerfeld wrote:
It looks very much like the sort of typo you would get from a mistranslation from assembly language if the target architecture had a *4-bit* processor. (This is also consistant with the "<<4"'s which show up in several places in the code).
I'll back up the disassembly theory. I've done it myself once when I lost some of my own source code from years previous and had to get out the dissassembler. Very painful work which resulted in a first set of source much like the "S1" sample posted here. Only difference was that I went back over the "first draft" after verifying it and cleaned it up somewhat. The poster either does not know 'C' or thinks that a cleanup will reveal his/her style. - Andy +-------------------------------------------------------------------------+ | Andrew Brown Internet <asb@nexor.co.uk> Telephone +44 115 952 0585 | | PGP (2048/9611055D): 69 AA EF 72 80 7A 63 3A C0 1F 9F 66 64 02 4C 88 | +-------------------------------------------------------------------------+
participants (3)
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Andy Brown -
Bill Sommerfeld -
Hal