implement Tonelli Shanks

PollardPminus1.hs

@@ -1,7 +1,7 @@
 import Text.Read (readMaybe)
 import System.Exit (exitSuccess)
-import Data.Bits
 import Utils (askNumber)
+import ModularArithmeticUtils (modExp)
 
 main :: IO ()
 main = do
@@ -41,10 +41,3 @@ pollardP1WithParams n a b = go a 2
                else if d == n
                then Nothing -- Found n itself, try with different parameters
                else go newA (k + 1)
-
--- Modular exponentiation: compute a^b mod m
-modExp :: Integer -> Integer -> Integer -> Integer
-modExp b 0 m = 1
-modExp b e m = t * modExp ((b * b) `mod` m) (shiftR e 1) m `mod` m
-            where t = if testBit e 0 then b `mod` m else 1
-