Implement division

1 files changed, 4 insertions, 0 deletions

diff --git a/ecc.hs b/ecc.hs
index 8146711..390bbb3 100644
--- a/ecc.hs
+++ b/ecc.hs
@@ -25,6 +25,10 @@ instance Num FieldElement where
   negate (FieldElement a b) = FieldElement (mod (b - a) b) b
   fromInteger _ = error "can't transform"
 
+instance Fractional FieldElement where
+  recip a = a ^ (prime a - 2)
+  fromRational _ = error "can't transform"
+
 aa =
   let a = FieldElement 2 31
       b = FieldElement 15 31