Switch the rest of the API to the new TimeStamp structure. Fix the TimeStamp structure to handle dates that are past the upper limit of DateTime.MaxValue.

NSspi/Contexts/ClientContext.cs

@@ -24,7 +24,7 @@ namespace NSspi.Contexts
 
         public SecurityStatus Init( byte[] serverToken, out byte[] outToken )
         {
-            long rawExpiry = 0;
+            TimeStamp rawExpiry = new TimeStamp();
 
             SecurityStatus status;
 
@@ -112,7 +112,7 @@ namespace NSspi.Contexts
                 this.Initialized = true;
                 outToken = null;
 
-                this.Expiry = TimeStamp.Calc( rawExpiry );
+                this.Expiry = rawExpiry.ToDateTime();
             }
             else if ( status == SecurityStatus.ContinueNeeded )
             {

NSspi/Contexts/ContextNativeMethods.cs

@@ -52,7 +52,7 @@ namespace NSspi.Contexts
             ref RawSspiHandle newContextHandle,
             IntPtr outputBuffer,
             ref ContextAttrib outputAttribs,
-            ref long expiry
+            ref TimeStamp expiry
         );
 
 
@@ -66,7 +66,7 @@ namespace NSspi.Contexts
             ref RawSspiHandle newContextHandle,
             IntPtr outputBuffer,
             ref ContextAttrib outputAttribs,
-            ref long expiry
+            ref TimeStamp expiry
         );
 
 
@@ -83,7 +83,7 @@ namespace NSspi.Contexts
             ref RawSspiHandle newContextHandle,
             IntPtr outputBuffer,
             ref ContextAttrib contextAttribs,
-            ref long expiry
+            ref TimeStamp expiry
         );
 
 
@@ -100,7 +100,7 @@ namespace NSspi.Contexts
             ref RawSspiHandle newContextHandle,
             IntPtr outputBuffer,
             ref ContextAttrib contextAttribs,
-            ref long expiry
+            ref TimeStamp expiry
         );
 
         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success )]

NSspi/Contexts/ServerContext.cs

@@ -30,7 +30,7 @@ namespace NSspi.Contexts
             SecureBuffer outBuffer = new SecureBuffer( new byte[12288], BufferType.Token );
 
             SecurityStatus status;
-            long rawExpiry = 0;
+            TimeStamp rawExpiry = new TimeStamp();
 
             SecureBufferAdapter clientAdapter;
             SecureBufferAdapter outAdapter;
@@ -87,7 +87,7 @@ namespace NSspi.Contexts
                     nextToken = null;
                 }
 
-                this.Expiry = TimeStamp.Calc( rawExpiry );
+                this.Expiry = rawExpiry.ToDateTime();
 
                 InitProviderCapabilities();
             }

NSspi/Credentials/Credential.cs

@@ -36,7 +36,7 @@ namespace NSspi.Credentials
         {
             string packageName;
             CredentialUse use;
-            long rawExpiry = 0;
+            TimeStamp rawExpiry = new TimeStamp();
 
             // -- Package --
             if ( package == SecurityPackage.Kerberos )
@@ -101,7 +101,7 @@ namespace NSspi.Credentials
                 throw new SSPIException( "Failed to call AcquireCredentialHandle", status );
             }
 
-            this.expiry = TimeStamp.Calc( rawExpiry );
+            this.expiry = rawExpiry.ToDateTime();
         }
 
         ~Credential()

NSspi/Credentials/CredentialNativeMethods.cs

@@ -47,7 +47,7 @@ namespace NSspi.Credentials
             IntPtr getKeyFunc,
             IntPtr getKeyData,
             ref RawSspiHandle credentialHandle,
-            ref long expiry
+            ref TimeStamp expiry
         );
 
         [ReliabilityContract( Consistency.WillNotCorruptState, Cer.Success )]

NSspi/TimeStamp.cs

@@ -1,18 +1,34 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading.Tasks;
 
 namespace NSspi
 {
-    public static class TimeStamp
+    [StructLayout( LayoutKind.Sequential )]
+    public struct TimeStamp
     {
         public static readonly DateTime Epoch = new DateTime( 1601, 1, 1, 0, 0, 0, DateTimeKind.Utc );
 
-        public static DateTime Calc( long rawExpiry )
+        private long time;
+
+        public DateTime ToDateTime()
         {
-            return TimeStamp.Epoch.AddTicks( rawExpiry );
+            ulong test = (ulong)this.time + (ulong)(Epoch.Ticks);
+
+            // Sometimes the value returned is massive, eg, 0x7fffff154e84ffff, which is a value 
+            // somewhere in the year 30848. This would overflow DateTime, since it peaks at 31-Dec-9999.
+            // http://stackoverflow.com/questions/24478056/
+            if ( test > (ulong)DateTime.MaxValue.Ticks )
+            {
+                return DateTime.MaxValue;
+            }
+            else
+            {
+                return DateTime.FromFileTimeUtc( this.time );
+            }
         }
     }
 }