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The following archive was created by hippie-mail 7.98617-22 on Sat Apr 10 1999 - 01:10:55
Mok-Kong Shen (mok-kong.shen@stud.uni-muenchen.de)
Mon, 03 Aug 1998 19:33:21 +0100
As a result of some discussions (with CWL and TPS) I have added
additional processing steps in my algorithms WEAK1 and WEAK3 to
do auto-keying with the purpose of achieving better diffusion.
The computation that is done on a record of 80 bytes (160 hex digits)
consists now of the following in each round:
a. Pseudo-random permutation of the hex digits.
b. Transformation of the hex digits with pseudo-randomly selected
substitution tables.
c. Circular shift of the words (groups of 8 hexs) by pseudo-
randomly determined number of bit positions.
d. Auto-keying of the words with a pseudo-randomly determined key.
e. Another circular shift of the words.
f. Another auto-keying of the words (in the opposite direction to
d in the word sequence).
g. Addition modulo 2^32 of the words with words of pseudo-random
bits obtained from a multiple seed PRNG (for WEAK1) or my
compound PRNG (for WEAK3).
I have done some time measurements on my codes. Excluding the setup
time, the pure processing time on a 200 MHZ processor for 1 round and
1 million bytes is 12.0, 2.7 and 11.3 sec for WEAK1, WEAK2 and WEAK3
respectively. Using, say, 5 rounds the processing speed is certainly
not impressively high but should be tolerable for ordinary usage by
our targeted poor men or laymen. (Note that we have done no
optimization and that the codes are in high-level language not
assembler language.)
The updated versions are accssible on my Web page
http://www.stud.uni-muenchen.de/~mok-kong.shen/
M. K. Shen
The following archive was created by hippie-mail 7.98617-22 on Sat Apr 10 1999 - 01:10:55