40 lines
727 B
Factor
40 lines
727 B
Factor
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USING: kernel math sequences namespaces ;
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IN: crypto.rc4
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! http://en.wikipedia.org/wiki/RC4_%28cipher%29
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<PRIVATE
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SYMBOL: i
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SYMBOL: j
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SYMBOL: s
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SYMBOL: key
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SYMBOL: l
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! key scheduling algorithm, initialize s
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: ksa ( -- )
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256 [ ] map s set
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0 j set
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256 [
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dup s get nth j get + over l get mod key get nth + 255 bitand j set
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dup j get s get exchange drop
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] each ;
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: generate ( -- n )
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i get 1+ 255 bitand i set
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j get i get s get nth + 255 bitand j set
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i get j get s get exchange
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i get s get nth j get s get nth + 255 bitand s get nth ;
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PRIVATE>
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: rc4 ( key -- )
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[
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[ key set ] keep
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length l set
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ksa
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0 i set
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0 j set
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] with-scope ;
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