Fix race condition

1 files changed, 9 insertions, 1 deletions

diff --git a/crypto/src/crypto/prng/SP800SecureRandom.cs b/crypto/src/crypto/prng/SP800SecureRandom.cs

index ac69e27e2..30c838c1b 100644
--- a/crypto/src/crypto/prng/SP800SecureRandom.cs
+++ b/crypto/src/crypto/prng/SP800SecureRandom.cs
@@ -81,7 +81,15 @@ namespace Org.BouncyCastle.Crypto.Prng
         /// <param name="additionalInput">optional additional input</param>
         public virtual void Reseed(byte[] additionalInput)
         {
-            mDrbg.Reseed(additionalInput);
+            lock (this)
+            {
+                if (mDrbg == null)
+                {
+                    mDrbg = mDrbgProvider.Get(mEntropySource);
+                }
+
+                mDrbg.Reseed(additionalInput);
+            }
         }
     }
 }