Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Configuration/Microsoft/Win32/SafeCryptContextHandle.cs

@@ -0,0 +1,36 @@
+//------------------------------------------------------------------------------
+// <copyright file="UnsafeNativeMethods.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace Microsoft.Win32 {
+    using System;
+    using System.Security.Permissions;
+    using Microsoft.Win32.SafeHandles;
+    using System.Configuration;
+
+    // Safehandle for crypt context handles
+    [System.Security.SuppressUnmanagedCodeSecurityAttribute()]
+    internal sealed class SafeCryptContextHandle : SafeHandleZeroOrMinusOneIsInvalid {
+        [SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode = true)]
+        internal SafeCryptContextHandle()
+            : base(true) {
+        }
+
+        [SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode = true)]
+        internal SafeCryptContextHandle(IntPtr handle, bool ownsHandle)
+            : base(ownsHandle) {
+            SetHandle(handle);
+        }
+
+        override protected bool ReleaseHandle() {
+            if (handle != IntPtr.Zero) {
+                UnsafeNativeMethods.CryptReleaseContext(this, 0);
+                return true;
+            }
+            return false;
+        }
+    }
+}
+