Port OpenPGP support for XDH, EdDSA from bc-java

- see https://github.com/bcgit/bc-csharp/issues/345

1 files changed, 11 insertions, 0 deletions

diff --git a/crypto/src/util/Arrays.cs b/crypto/src/util/Arrays.cs

index 936e510be..8b10ae6a3 100644
--- a/crypto/src/util/Arrays.cs
+++ b/crypto/src/util/Arrays.cs
@@ -884,6 +884,17 @@ namespace Org.BouncyCastle.Utilities
             return result;
         }
 
+        public static T[] Prepend<T>(T[] a, T b)
+        {
+            if (a == null)
+                return new T[1]{ b };
+
+            T[] result = new T[1 + a.Length];
+            result[0] = b;
+            a.CopyTo(result, 1);
+            return result;
+        }
+
         public static byte[] Reverse(byte[] a)
         {
             if (a == null)