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Assets/BestHTTP/SecureProtocol/crypto/modes/gcm/Tables1kGcmExponentiator.cs

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+#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
+
+using System;
+using System.Collections;
+
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Modes.Gcm
+{
+    public class Tables1kGcmExponentiator
+        : IGcmExponentiator
+    {
+        // A lookup table of the power-of-two powers of 'x'
+        // - lookupPowX2[i] = x^(2^i)
+        private IList lookupPowX2;
+
+        public void Init(byte[] x)
+        {
+            uint[] y = GcmUtilities.AsUints(x);
+            if (lookupPowX2 != null && Arrays.AreEqual(y, (uint[])lookupPowX2[0]))
+                return;
+
+            lookupPowX2 = Platform.CreateArrayList(8);
+            lookupPowX2.Add(y);
+        }
+
+        public void ExponentiateX(long pow, byte[] output)
+        {
+            uint[] y = GcmUtilities.OneAsUints();
+            int bit = 0;
+            while (pow > 0)
+            {
+                if ((pow & 1L) != 0)
+                {
+                    EnsureAvailable(bit);
+                    GcmUtilities.Multiply(y, (uint[])lookupPowX2[bit]);
+                }
+                ++bit;
+                pow >>= 1;
+            }
+
+            GcmUtilities.AsBytes(y, output);
+        }
+
+        private void EnsureAvailable(int bit)
+        {
+            int count = lookupPowX2.Count;
+            if (count <= bit)
+            {
+                uint[] tmp = (uint[])lookupPowX2[count - 1];
+                do
+                {
+                    tmp = Arrays.Clone(tmp);
+                    GcmUtilities.Multiply(tmp, tmp);
+                    lookupPowX2.Add(tmp);
+                }
+                while (++count <= bit);
+            }
+        }
+    }
+}
+
+#endif