From f65d8b967df6eb86ec5f67e9bd94f6993c9e07bb Mon Sep 17 00:00:00 2001
From: Peter Dettman <peter.dettman@bouncycastle.org>
Date: Sat, 25 Jan 2014 20:45:34 +0700
Subject: Implement Sqrt in F2m

---
 crypto/src/math/ec/ECFieldElement.cs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

(limited to 'crypto/src/math')

diff --git a/crypto/src/math/ec/ECFieldElement.cs b/crypto/src/math/ec/ECFieldElement.cs
index 22cd1e0e8..ac9c62807 100644
--- a/crypto/src/math/ec/ECFieldElement.cs
+++ b/crypto/src/math/ec/ECFieldElement.cs
@@ -1166,7 +1166,15 @@ namespace Org.BouncyCastle.Math.EC
 
         public override ECFieldElement Sqrt()
         {
-            throw new ArithmeticException("Not implemented");
+            LongArray root = this.x;
+            if (root.IsOne() || root.IsZero())
+                return this;
+
+            for (int i = 1; i < m; ++i)
+            {
+                root = root.ModSquare(m, ks);
+            }
+            return new F2mFieldElement(m, ks, root);
         }
 
         /**
-- 
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