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TwoTenPvPTwoTenPvP
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Merge pull request #29 from GabrielTofvesson/master
Added Diffie Hellman
2 parents 0593de4 + 944def3 commit b618ec3

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‎MLAPI/MLAPI.csproj

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<GenerateSerializationAssemblies>Auto</GenerateSerializationAssemblies>
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</PropertyGroup>
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<ItemGroup>
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<Reference Include="IntXLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=1744b76c74eaee1e, processorArchitecture=MSIL">
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<HintPath>..\packages\IntX.1.0.1.0\lib\net20\IntXLib.dll</HintPath>
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</Reference>
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<Reference Include="System" />
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<Reference Include="System.Core" />
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<Reference Include="System.Xml.Linq" />
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<Compile Include="Data\ClientIdKey.cs" />
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<Compile Include="NetworkingManagerComponents\MessageChunker.cs" />
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</ItemGroup>
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<ItemGroup>
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<None Include="packages.config" />
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</ItemGroup>
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<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
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</Project>

‎MLAPI/NetworkingManagerComponents/DiffieHellman.cs

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using System;
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using IntXLib;
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using System.Text;
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using System.Security.Cryptography;
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namespace ECDH
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{
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public class EllipticDiffieHellman
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{
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protected static readonly RNGCryptoServiceProvider rand = new RNGCryptoServiceProvider();
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public static readonly IntX DEFAULT_PRIME = (new IntX(1) << 255) - 19;
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public static readonly IntX DEFAULT_ORDER = (new IntX(1) << 252) + IntX.Parse("27742317777372353535851937790883648493");
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public static readonly EllipticCurve DEFAULT_CURVE = new EllipticCurve(486662, 1, DEFAULT_PRIME, EllipticCurve.CurveType.Montgomery);
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public static readonly CurvePoint DEFAULT_GENERATOR = new CurvePoint(9, IntX.Parse("14781619447589544791020593568409986887264606134616475288964881837755586237401"));
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protected readonly EllipticCurve curve;
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public readonly IntX priv;
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protected readonly CurvePoint generator, pub;
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public EllipticDiffieHellman(EllipticCurve curve, CurvePoint generator, IntX order, byte[] priv = null)
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{
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this.curve = curve;
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this.generator = generator;
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// Generate private key
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if (priv == null)
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{
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byte[] max = order.ToArray();
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do
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{
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byte[] p1 = new byte[5 /*rand.Next(max.Length) + 1*/];
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rand.GetBytes(p1);
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if (p1.Length == max.Length) p1[p1.Length - 1] %= max[max.Length - 1];
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else p1[p1.Length - 1] &= 127;
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this.priv = DHHelper.FromArray(p1);
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} while (this.priv<2);
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}
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else this.priv = DHHelper.FromArray(priv);
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// Generate public key
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pub = curve.Multiply(generator, this.priv);
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}
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public byte[] GetPublicKey()
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{
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byte[] p1 = pub.X.ToArray();
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byte[] p2 = pub.Y.ToArray();
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byte[] ser = new byte[4 + p1.Length + p2.Length];
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ser[0] = (byte)(p1.Length & 255);
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ser[1] = (byte)((p1.Length >> 8) & 255);
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ser[2] = (byte)((p1.Length >> 16) & 255);
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ser[3] = (byte)((p1.Length >> 24) & 255);
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Array.Copy(p1, 0, ser, 4, p1.Length);
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Array.Copy(p2, 0, ser, 4 + p1.Length, p2.Length);
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return ser;
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}
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public byte[] GetPrivateKey() => priv.ToArray();
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public byte[] GetSharedSecret(byte[] pK)
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{
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byte[] p1 = new byte[pK[0] | (pK[1]<<8) | (pK[2]<<16) | (pK[3]<<24)]; // Reconstruct x-axis size
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byte[] p2 = new byte[pK.Length - p1.Length - 4];
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Array.Copy(pK, 4, p1, 0, p1.Length);
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Array.Copy(pK, 4 + p1.Length, p2, 0, p2.Length);
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CurvePoint remotePublic = new CurvePoint(DHHelper.FromArray(p1), DHHelper.FromArray(p2));
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byte[] secret = curve.Multiply(remotePublic, priv).X.ToArray(); // Use the x-coordinate as the shared secret
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// PBKDF2-HMAC-SHA1 (Common shared secret generation method)
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return new Rfc2898DeriveBytes(secret, Encoding.UTF8.GetBytes("P1sN0R4inb0wPl5P1sPls"), 1000).GetBytes(32);
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}
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}
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public static class DHHelper
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{
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public static byte[] ToArray(this IntX v)
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{
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v.GetInternalState(out uint[] digits, out bool negative);
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byte[] b = DigitConverter.ToBytes(digits);
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byte[] b1 = new byte[b.Length];
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Array.Copy(b, b1, b.Length);
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b1[b.Length] = (byte)(negative ? 1 : 0);
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return b1;
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}
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public static IntX FromArray(byte[] b)
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{
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if (b.Length == 0) return new IntX();
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byte[] b1 = new byte[b.Length - 1];
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Array.Copy(b, b1, b1.Length);
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uint[] u = DigitConverter.FromBytes(b1);
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return new IntX(u, b[b.Length - 1]==1);
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}
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public static bool BitAt(this uint[] data, long index) => (data[index/8]&(1<<(int)(index%8)))!=0;
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public static IntX Abs(this IntX i) => i < 0 ? -i : i;
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}
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}

‎MLAPI/NetworkingManagerComponents/EllipticCurve.cs

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using System;
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using System.Collections.Generic;
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using IntXLib;
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namespace ECDH
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{
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public class CurvePoint
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{
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public static readonly CurvePoint POINT_AT_INFINITY = new CurvePoint();
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public IntX X { get; private set; }
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public IntX Y { get; private set; }
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private bool pai = false;
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public CurvePoint(IntX x, IntX y)
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{
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X = x;
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Y = y;
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}
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private CurvePoint() { pai = true; } // Accessing corrdinates causes undocumented behaviour
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public override string ToString()
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{
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return pai ? "(POINT_AT_INFINITY)" : "(" + X + ", " + Y + ")";
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}
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}
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public class EllipticCurve
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{
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public enum CurveType { Weierstrass, Montgomery }
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protected readonly IntX a, b, modulo;
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protected readonly CurveType type;
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public EllipticCurve(IntX a, IntX b, IntX modulo, CurveType type = CurveType.Weierstrass)
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{
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if (
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(type==CurveType.Weierstrass && (4 * a * a * a) + (27 * b * b) == 0) || // Unfavourable Weierstrass curves
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(type==CurveType.Montgomery && b * (a * a - 4)==0) // Unfavourable Montgomery curves
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) throw new Exception("Unfavourable curve");
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this.a = a;
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this.b = b;
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this.modulo = modulo;
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this.type = type;
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}
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public CurvePoint Add(CurvePoint p1, CurvePoint p2)
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{
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#if SAFE_MATH
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CheckOnCurve(p1);
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CheckOnCurve(p2);
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#endif
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// Special cases
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if (p1 == CurvePoint.POINT_AT_INFINITY && p2 == CurvePoint.POINT_AT_INFINITY) return CurvePoint.POINT_AT_INFINITY;
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else if (p1 == CurvePoint.POINT_AT_INFINITY) return p2;
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else if (p2 == CurvePoint.POINT_AT_INFINITY) return p1;
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else if (p1.X == p2.X && p1.Y == Inverse(p2).Y) return CurvePoint.POINT_AT_INFINITY;
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IntX x3 = 0, y3 = 0;
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if (type == CurveType.Weierstrass)
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{
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IntX slope = p1.X == p2.X && p1.Y == p2.Y ? Mod((3 * p1.X * p1.X + a) * MulInverse(2 * p1.Y)) : Mod(Mod(p2.Y - p1.Y) * MulInverse(p2.X - p1.X));
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x3 = Mod((slope * slope) - p1.X - p2.X);
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y3 = Mod(-((slope * x3) + p1.Y - (slope * p1.X)));
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}
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else if (type == CurveType.Montgomery)
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{
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if ((p1.X == p2.X && p1.Y == p2.Y))
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{
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IntX q = 3 * p1.X;
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IntX w = q * p1.X;
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IntX e = 2 * a;
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IntX r = e * p1.X;
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IntX t = 2 * b;
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IntX y = t * p1.Y;
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IntX u = MulInverse(y);
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IntX o = w + e + 1;
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IntX p = o * u;
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}
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IntX co = p1.X == p2.X && p1.Y == p2.Y ? Mod((3 * p1.X * p1.X + 2 * a * p1.X + 1) * MulInverse(2 * b * p1.Y)) : Mod(Mod(p2.Y - p1.Y) * MulInverse(p2.X - p1.X)); // Compute a commonly used coefficient
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x3 = Mod(b * co * co - a - p1.X - p2.X);
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y3 = Mod(((2 * p1.X + p2.X + a) * co) - (b * co * co * co) - p1.Y);
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}
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return new CurvePoint(x3, y3);
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}
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public CurvePoint Multiply(CurvePoint p, IntX scalar)
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{
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if (scalar <= 0) throw new Exception("Cannot multiply by a scalar which is <= 0");
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if (p == CurvePoint.POINT_AT_INFINITY) return CurvePoint.POINT_AT_INFINITY;
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CurvePoint p1 = new CurvePoint(p.X, p.Y);
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scalar.GetInternalState(out uint[] u, out bool b);
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long high_bit = -1;
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for (int i = u.Length - 1; i>=0; --i)
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if (u[i] != 0)
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{
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for(int j = 31; j>=0; --j)
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if ((u[i] & (1<<j))!=0)
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{
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high_bit = j + i * 32;
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goto Next;
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}
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}
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Next:
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// Double-and-add method
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while(high_bit >= 0)
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{
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p1 = Add(p1, p1); // Double
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if ((u.BitAt(high_bit)))
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p1 = Add(p1, p); // Add
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--high_bit;
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}
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return p1;
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}
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protected IntX MulInverse(IntX eq) => MulInverse(eq, modulo);
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public static IntX MulInverse(IntX eq, IntX modulo)
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{
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eq = Mod(eq, modulo);
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Stack<IntX> collect = new Stack<IntX>();
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IntX v = modulo; // Copy modulo
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IntX m;
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while((m = v % eq) != 0)
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{
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collect.Push(-v/eq/*-(m.l_div)*/);
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v = eq;
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eq = m;
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}
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if (collect.Count == 0) return 1;
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v = 1;
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m = collect.Pop();
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while (collect.Count > 0)
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{
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eq = m;
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m = v + (m * collect.Pop());
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v = eq;
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}
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return Mod(m, modulo);
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}
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public CurvePoint Inverse(CurvePoint p) => Inverse(p, modulo);
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protected static CurvePoint Inverse(CurvePoint p, IntX modulo) => new CurvePoint(p.X, Mod(-p.Y, modulo));
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public bool IsOnCurve(CurvePoint p)
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{
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try { CheckOnCurve(p); }
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catch { return false; }
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return true;
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}
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protected void CheckOnCurve(CurvePoint p)
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{
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if (
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p!=CurvePoint.POINT_AT_INFINITY && // The point at infinity is asserted to be on the curve
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(type == CurveType.Weierstrass && Mod(p.Y * p.Y) != Mod((p.X * p.X * p.X) + (p.X * a) + b)) || // Weierstrass formula
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(type == CurveType.Montgomery && Mod(b * p.Y * p.Y) != Mod((p.X * p.X * p.X) + (p.X * p.X * a) + p.X)) // Montgomery formula
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) throw new Exception("Point is not on curve");
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}
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protected IntX Mod(IntX b) => Mod(b, modulo);
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private static IntX Mod(IntX x, IntX m)
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{
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IntX r = x.Abs() > m ? x % m : x;
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return r < 0 ? r + m : r;
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}
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protected static IntX ModPow(IntX x, IntX power, IntX prime)
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{
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IntX result = 1;
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bool setBit = false;
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while(power > 0)
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{
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x %= prime;
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setBit = (power & 1) == 1;
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power >>= 1;
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if (setBit) result *= x;
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x *= x;
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}
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return result;
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}
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}
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}

‎MLAPI/packages.config

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<?xml version="1.0" encoding="utf-8"?>
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<packages>
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<package id="IntX" version="1.0.1.0" targetFramework="net35" />
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</packages>

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