1 files changed, 3 insertions, 3 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP256K1Field.cs b/crypto/src/math/ec/custom/sec/SecP256K1Field.cs
index 91144c017..6e834beb3 100644
--- a/crypto/src/math/ec/custom/sec/SecP256K1Field.cs
+++ b/crypto/src/math/ec/custom/sec/SecP256K1Field.cs
@@ -62,12 +62,12 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
         {
             if ((x[0] & 1) == 0)
             {
-                Nat256.ShiftDownBit(x, 0, z);
+                Nat.ShiftDownBit(8, x, 0, z);
             }
             else
             {
                 uint c = Nat256.Add(x, P, z);
-                Nat256.ShiftDownBit(z, c, z);
+                Nat.ShiftDownBit(8, z, c);
             }
         }
 
@@ -157,7 +157,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
 
         public static void Twice(uint[] x, uint[] z)
         {
-            uint c = Nat256.ShiftUpBit(x, 0, z);
+            uint c = Nat.ShiftUpBit(8, x, 0, z);
             if (c != 0 || (z[7] == P7 && Nat256.Gte(z, P)))
             {
                 Nat256.Add33To(PInv33, z);