Add sanity checks on scalar mult. outputs

1 files changed, 8 insertions, 0 deletions

diff --git a/crypto/src/math/ec/rfc7748/X448Field.cs b/crypto/src/math/ec/rfc7748/X448Field.cs

index f1e89e520..14c9b4879 100644
--- a/crypto/src/math/ec/rfc7748/X448Field.cs
+++ b/crypto/src/math/ec/rfc7748/X448Field.cs
@@ -1009,6 +1009,14 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             z[15] = z15;
         }
 
+        public static void SubOne(uint[] z)
+        {
+            uint[] one = Create();
+            one[0] = 1U;
+
+            Sub(z, one, z);
+        }
+
         public static void Zero(uint[] z)
         {
             for (int i = 0; i < Size; ++i)