21 lines
542 B
Factor
21 lines
542 B
Factor
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USING: kernel math errors math-contrib ;
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IN: crypto
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! As per http://www.cyphercalc.com/index.htm
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: montgomery-image ( a n -- a' )
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#! a' = a * nextpowerof2(a) mod n
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>r dup next-power-of-2 * r> mod ;
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! : montgomery* ( a b -- a*b )
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! "todo" throw ;
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: montgomery-r^2 ( n -- a )
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#! ans = r^2 mod n, where r = nextpowerof2(n)
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[ next-power-of-2 sq ] keep mod ;
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: montgomery-n0' ( n0 size -- n0' )
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#! size should be a multiple of 2, n0 is odd and n0 < 2^size
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#! n0 * n0' = -1 mod 2^w
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2 swap ^ swap neg mod-inv ;
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