diff --git a/Contexts/Context.cs b/Contexts/Context.cs
index 5d2a0ca..37ebbf3 100644
--- a/Contexts/Context.cs
+++ b/Contexts/Context.cs
@@ -279,37 +279,12 @@ namespace NSspi.Contexts
 
             using ( adapter = new SecureBufferAdapter( new[] { dataBuffer, signatureBuffer } ) )
             {
-                bool gotRef = false;
-                
-                RuntimeHelpers.PrepareConstrainedRegions();
-                try
-                {
-                    this.ContextHandle.DangerousAddRef( ref gotRef );
-                }
-                catch ( Exception )
-                {
-                    if ( gotRef )
-                    {
-                        this.ContextHandle.DangerousRelease();
-                        gotRef = false;
-                    }
-
-                    throw;
-                }
-                finally
-                {
-                    if ( gotRef )
-                    {
-                        status = ContextNativeMethods.MakeSignature(
-                            ref this.ContextHandle.rawHandle,
-                            0,
-                            adapter.Handle,
-                            0
-                        );
-
-                        this.ContextHandle.DangerousRelease();
-                    }
-                }
+                status = ContextNativeMethods.SafeMakeSignature(
+                    this.ContextHandle,
+                    0,
+                    adapter,
+                    0
+                );
             }
 
             if ( status != SecurityStatus.OK )
@@ -384,37 +359,12 @@ namespace NSspi.Contexts
 
             using ( adapter = new SecureBufferAdapter( new[] { dataBuffer, signatureBuffer } ) )
             {
-                bool gotRef = false;
-
-                RuntimeHelpers.PrepareConstrainedRegions();
-                try
-                {
-                    this.ContextHandle.DangerousAddRef( ref gotRef );
-                }
-                catch ( Exception )
-                {
-                    if ( gotRef )
-                    {
-                        this.ContextHandle.DangerousRelease();
-                        gotRef = false;
-                    }
-
-                    throw;
-                }
-                finally
-                {
-                    if ( gotRef )
-                    {
-                        status = ContextNativeMethods.VerifySignature(
-                            ref this.ContextHandle.rawHandle,
-                            adapter.Handle,
-                            0,
-                            0
-                        );
-
-                        this.ContextHandle.DangerousRelease();
-                    }
-                }
+                status = ContextNativeMethods.SafeVerifySignature(
+                    this.ContextHandle,
+                    0,
+                    adapter,
+                    0
+                );
             }
 
             if ( status == SecurityStatus.OK )
diff --git a/Contexts/ContextNativeMethods.cs b/Contexts/ContextNativeMethods.cs
index 57ce8c2..462a07f 100644
--- a/Contexts/ContextNativeMethods.cs
+++ b/Contexts/ContextNativeMethods.cs
@@ -257,5 +257,89 @@ namespace NSspi.Contexts
 
             return status;
         }
+
+        internal static SecurityStatus SafeMakeSignature(
+            SafeContextHandle handle,
+            int qualityOfProtection,
+            SecureBufferAdapter adapter,
+            int sequenceNumber )
+        {
+            bool gotRef = false;
+            SecurityStatus status = SecurityStatus.InternalError;
+
+            RuntimeHelpers.PrepareConstrainedRegions();
+            try
+            {
+                handle.DangerousAddRef( ref gotRef );
+            }
+            catch ( Exception )
+            {
+                if ( gotRef )
+                {
+                    handle.DangerousRelease();
+                    gotRef = false;
+                }
+
+                throw;
+            }
+            finally
+            {
+                if ( gotRef )
+                {
+                    status = ContextNativeMethods.MakeSignature(
+                        ref handle.rawHandle,
+                        0,
+                        adapter.Handle,
+                        0
+                    );
+
+                    handle.DangerousRelease();
+                }
+            }
+
+            return status;
+        }
+
+        internal static SecurityStatus SafeVerifySignature(
+            SafeContextHandle handle,
+            int qualityOfProtection,
+            SecureBufferAdapter adapter,
+            int sequenceNumber )
+        {
+            bool gotRef = false;
+            SecurityStatus status = SecurityStatus.InternalError;
+
+            RuntimeHelpers.PrepareConstrainedRegions();
+            try
+            {
+                handle.DangerousAddRef( ref gotRef );
+            }
+            catch ( Exception )
+            {
+                if ( gotRef )
+                {
+                    handle.DangerousRelease();
+                    gotRef = false;
+                }
+
+                throw;
+            }
+            finally
+            {
+                if ( gotRef )
+                {
+                    status = ContextNativeMethods.VerifySignature(
+                        ref handle.rawHandle,
+                        adapter.Handle,
+                        0,
+                        0
+                    );
+
+                    handle.DangerousRelease();
+                }
+            }
+
+            return status;
+        }
     }
 }