added missing null check

1 files changed, 5 insertions, 1 deletions

diff --git a/crypto/src/crypto/digests/DSTU7564Digest.cs b/crypto/src/crypto/digests/DSTU7564Digest.cs

index 12057b146..9de41dd6b 100644
--- a/crypto/src/crypto/digests/DSTU7564Digest.cs
+++ b/crypto/src/crypto/digests/DSTU7564Digest.cs
@@ -282,7 +282,11 @@ namespace Org.BouncyCastle.Crypto.Digests
             bufOff = 0;
 
             Arrays.Fill(buf, (byte)0);
-            Arrays.Fill(padded_, (byte)0);
+
+            if (padded_ != null)
+            {
+                Arrays.Fill(padded_, (byte)0);
+            }
         }
 
           public int GetDigestSize()