64 lines
1.9 KiB
C#
64 lines
1.9 KiB
C#
#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
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#pragma warning disable
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using System;
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using System.Collections.Generic;
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namespace Best.HTTP.SecureProtocol.Org.BouncyCastle.Crypto.Modes.Gcm
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{
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public class Tables1kGcmExponentiator
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: IGcmExponentiator
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{
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// A lookup table of the power-of-two powers of 'x'
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// - lookupPowX2[i] = x^(2^i)
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private IList<GcmUtilities.FieldElement> lookupPowX2;
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public void Init(byte[] x)
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{
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GcmUtilities.FieldElement y;
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GcmUtilities.AsFieldElement(x, out y);
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if (lookupPowX2 != null && y.Equals(lookupPowX2[0]))
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return;
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lookupPowX2 = new List<GcmUtilities.FieldElement>(8);
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lookupPowX2.Add(y);
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}
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public void ExponentiateX(long pow, byte[] output)
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{
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GcmUtilities.FieldElement y;
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GcmUtilities.One(out y);
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int bit = 0;
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while (pow > 0)
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{
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if ((pow & 1L) != 0)
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{
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EnsureAvailable(bit);
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GcmUtilities.FieldElement powX2 = (GcmUtilities.FieldElement)lookupPowX2[bit];
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GcmUtilities.Multiply(ref y, ref powX2);
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}
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++bit;
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pow >>= 1;
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}
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GcmUtilities.AsBytes(ref y, output);
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}
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private void EnsureAvailable(int bit)
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{
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int count = lookupPowX2.Count;
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if (count <= bit)
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{
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GcmUtilities.FieldElement powX2 = (GcmUtilities.FieldElement)lookupPowX2[count - 1];
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do
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{
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GcmUtilities.Square(ref powX2);
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lookupPowX2.Add(powX2);
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}
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while (++count <= bit);
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}
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}
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}
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}
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#pragma warning restore
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#endif
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