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+ DC79CACA9A6A286AEC3B4484F21E55F8A61AE1B991CE17909CB3DAFE0EF2F761ECA6043CF6A86F10EE7E8582DD95F233E271978210DD8778F4140D51DDC8E040
ffa/libffa/fz_prime.ads
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615 ------------------------------------------------------------------------------
616 ------------------------------------------------------------------------------
617 -- This file is part of 'Finite Field Arithmetic', aka 'FFA'.               --
618 --                                                                          --
619 -- (C) 2019 Stanislav Datskovskiy ( www.loper-os.org )                      --
620 -- http://wot.deedbot.org/17215D118B7239507FAFED98B98228A001ABFFC7.html     --
621 --                                                                          --
622 -- You do not have, nor can you ever acquire the right to use, copy or      --
623 -- distribute this software ; Should you use this software for any purpose, --
624 -- or copy and distribute it to anyone or in any manner, you are breaking   --
625 -- the laws of whatever soi-disant jurisdiction, and you promise to         --
626 -- continue doing so for the indefinite future. In any case, please         --
627 -- always : read and understand any software ; verify any PGP signatures    --
628 -- that you use - for any purpose.                                          --
629 --                                                                          --
630 -- See also http://trilema.com/2015/a-new-software-licensing-paradigm .     --
631 ------------------------------------------------------------------------------
632 ------------------------------------------------------------------------------
633 
634 with Words;   use Words;
635 with FZ_Type; use FZ_Type;
636 
637 
638 package FZ_Prime is
639    
640    pragma Pure;
641    
642    -- Constant-Time Miller-Rabin Test on N using the given Witness.
643    -- Witness will be used as-is if it conforms to the valid bounds,
644    -- i.e. 2 <= Witness <= N - 2; otherwise will be transformed into a
645    -- valid Witness via modular arithmetic.
646    -- Outputs ONE if N WAS FOUND composite; ZERO if NOT FOUND.
647    -- Handles degenerate cases of N that M-R per se cannot eat:
648    -- N=0, N=1: ALWAYS 'FOUND COMPOSITE'; 2, 3 - ALWAYS 'NOT FOUND'.
649    -- If N is Even and not equal to 2, N is ALWAYS 'FOUND COMPOSITE.'
650    -- For ALL other N, the output is equal to that of the M-R test.
651    function FZ_MR_Composite_On_Witness(N       : in  FZ;
652                                        Witness : in  FZ) return WBool
653      with Pre => N'Length = Witness'Length;
654    
655 end FZ_Prime;