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Merge pull request #29 from GabrielTofvesson/master

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Added Diffie Hellman
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Albin Corén 2018-03-29 08:54:00 +02:00 committed by GitHub
commit b618ec30fb
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6
MLAPI/MLAPI.csproj
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@ -44,6 +44,9 @@
<GenerateSerializationAssemblies>Auto</GenerateSerializationAssemblies>
</PropertyGroup>
<ItemGroup>
<Reference Include="IntXLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=1744b76c74eaee1e, processorArchitecture=MSIL">
<HintPath>..\packages\IntX.1.0.1.0\lib\net20\IntXLib.dll</HintPath>
</Reference>
<Reference Include="System" />
<Reference Include="System.Core" />
<Reference Include="System.Xml.Linq" />
@ -79,5 +82,8 @@
<Compile Include="Data\ClientIdKey.cs" />
<Compile Include="NetworkingManagerComponents\MessageChunker.cs" />
</ItemGroup>
<ItemGroup>
<None Include="packages.config" />
</ItemGroup>
<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
</Project>

104
MLAPI/NetworkingManagerComponents/DiffieHellman.cs Normal file
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using System;
using IntXLib;
using System.Text;
using System.Security.Cryptography;
namespace ECDH
{
public class EllipticDiffieHellman
{
protected static readonly RNGCryptoServiceProvider rand = new RNGCryptoServiceProvider();
public static readonly IntX DEFAULT_PRIME = (new IntX(1) << 255) - 19;
public static readonly IntX DEFAULT_ORDER = (new IntX(1) << 252) + IntX.Parse("27742317777372353535851937790883648493");
public static readonly EllipticCurve DEFAULT_CURVE = new EllipticCurve(486662, 1, DEFAULT_PRIME, EllipticCurve.CurveType.Montgomery);
public static readonly CurvePoint DEFAULT_GENERATOR = new CurvePoint(9, IntX.Parse("14781619447589544791020593568409986887264606134616475288964881837755586237401"));
protected readonly EllipticCurve curve;
public readonly IntX priv;
protected readonly CurvePoint generator, pub;
public EllipticDiffieHellman(EllipticCurve curve, CurvePoint generator, IntX order, byte[] priv = null)
{
this.curve = curve;
this.generator = generator;
// Generate private key
if (priv == null)
{
byte[] max = order.ToArray();
do
{
byte[] p1 = new byte[5 /*rand.Next(max.Length) + 1*/];
rand.GetBytes(p1);
if (p1.Length == max.Length) p1[p1.Length - 1] %= max[max.Length - 1];
else p1[p1.Length - 1] &= 127;
this.priv = DHHelper.FromArray(p1);
} while (this.priv<2);
}
else this.priv = DHHelper.FromArray(priv);
// Generate public key
pub = curve.Multiply(generator, this.priv);
}
public byte[] GetPublicKey()
{
byte[] p1 = pub.X.ToArray();
byte[] p2 = pub.Y.ToArray();
byte[] ser = new byte[4 + p1.Length + p2.Length];
ser[0] = (byte)(p1.Length & 255);
ser[1] = (byte)((p1.Length >> 8) & 255);
ser[2] = (byte)((p1.Length >> 16) & 255);
ser[3] = (byte)((p1.Length >> 24) & 255);
Array.Copy(p1, 0, ser, 4, p1.Length);
Array.Copy(p2, 0, ser, 4 + p1.Length, p2.Length);
return ser;
}
public byte[] GetPrivateKey() => priv.ToArray();
public byte[] GetSharedSecret(byte[] pK)
{
byte[] p1 = new byte[pK[0] | (pK[1]<<8) | (pK[2]<<16) | (pK[3]<<24)]; // Reconstruct x-axis size
byte[] p2 = new byte[pK.Length - p1.Length - 4];
Array.Copy(pK, 4, p1, 0, p1.Length);
Array.Copy(pK, 4 + p1.Length, p2, 0, p2.Length);
CurvePoint remotePublic = new CurvePoint(DHHelper.FromArray(p1), DHHelper.FromArray(p2));
byte[] secret = curve.Multiply(remotePublic, priv).X.ToArray(); // Use the x-coordinate as the shared secret
// PBKDF2-HMAC-SHA1 (Common shared secret generation method)
return new Rfc2898DeriveBytes(secret, Encoding.UTF8.GetBytes("P1sN0R4inb0wPl5P1sPls"), 1000).GetBytes(32);
}
}
public static class DHHelper
{
public static byte[] ToArray(this IntX v)
{
v.GetInternalState(out uint[] digits, out bool negative);
byte[] b = DigitConverter.ToBytes(digits);
byte[] b1 = new byte[b.Length];
Array.Copy(b, b1, b.Length);
b1[b.Length] = (byte)(negative ? 1 : 0);
return b1;
}
public static IntX FromArray(byte[] b)
{
if (b.Length == 0) return new IntX();
byte[] b1 = new byte[b.Length - 1];
Array.Copy(b, b1, b1.Length);
uint[] u = DigitConverter.FromBytes(b1);
return new IntX(u, b[b.Length - 1]==1);
}
public static bool BitAt(this uint[] data, long index) => (data[index/8]&(1<<(int)(index%8)))!=0;
public static IntX Abs(this IntX i) => i < 0 ? -i : i;
}
}

189
MLAPI/NetworkingManagerComponents/EllipticCurve.cs Normal file
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using System;
using System.Collections.Generic;
using IntXLib;
namespace ECDH
{
public class CurvePoint
{
public static readonly CurvePoint POINT_AT_INFINITY = new CurvePoint();
public IntX X { get; private set; }
public IntX Y { get; private set; }
private bool pai = false;
public CurvePoint(IntX x, IntX y)
{
X = x;
Y = y;
}
private CurvePoint() { pai = true; } // Accessing corrdinates causes undocumented behaviour
public override string ToString()
{
return pai ? "(POINT_AT_INFINITY)" : "(" + X + ", " + Y + ")";
}
}
public class EllipticCurve
{
public enum CurveType { Weierstrass, Montgomery }
protected readonly IntX a, b, modulo;
protected readonly CurveType type;
public EllipticCurve(IntX a, IntX b, IntX modulo, CurveType type = CurveType.Weierstrass)
{
if (
(type==CurveType.Weierstrass && (4 * a * a * a) + (27 * b * b) == 0) || // Unfavourable Weierstrass curves
(type==CurveType.Montgomery && b * (a * a - 4)==0) // Unfavourable Montgomery curves
) throw new Exception("Unfavourable curve");
this.a = a;
this.b = b;
this.modulo = modulo;
this.type = type;
}
public CurvePoint Add(CurvePoint p1, CurvePoint p2)
{
#if SAFE_MATH
CheckOnCurve(p1);
CheckOnCurve(p2);
#endif
// Special cases
if (p1 == CurvePoint.POINT_AT_INFINITY && p2 == CurvePoint.POINT_AT_INFINITY) return CurvePoint.POINT_AT_INFINITY;
else if (p1 == CurvePoint.POINT_AT_INFINITY) return p2;
else if (p2 == CurvePoint.POINT_AT_INFINITY) return p1;
else if (p1.X == p2.X && p1.Y == Inverse(p2).Y) return CurvePoint.POINT_AT_INFINITY;
IntX x3 = 0, y3 = 0;
if (type == CurveType.Weierstrass)
{
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));
x3 = Mod((slope * slope) - p1.X - p2.X);
y3 = Mod(-((slope * x3) + p1.Y - (slope * p1.X)));
}
else if (type == CurveType.Montgomery)
{
if ((p1.X == p2.X && p1.Y == p2.Y))
{
IntX q = 3 * p1.X;
IntX w = q * p1.X;
IntX e = 2 * a;
IntX r = e * p1.X;
IntX t = 2 * b;
IntX y = t * p1.Y;
IntX u = MulInverse(y);
IntX o = w + e + 1;
IntX p = o * u;
}
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
x3 = Mod(b * co * co - a - p1.X - p2.X);
y3 = Mod(((2 * p1.X + p2.X + a) * co) - (b * co * co * co) - p1.Y);
}
return new CurvePoint(x3, y3);
}
public CurvePoint Multiply(CurvePoint p, IntX scalar)
{
if (scalar <= 0) throw new Exception("Cannot multiply by a scalar which is <= 0");
if (p == CurvePoint.POINT_AT_INFINITY) return CurvePoint.POINT_AT_INFINITY;
CurvePoint p1 = new CurvePoint(p.X, p.Y);
scalar.GetInternalState(out uint[] u, out bool b);
long high_bit = -1;
for (int i = u.Length - 1; i>=0; --i)
if (u[i] != 0)
{
for(int j = 31; j>=0; --j)
if ((u[i] & (1<<j))!=0)
{
high_bit = j + i * 32;
goto Next;
}
}
Next:
// Double-and-add method
while(high_bit >= 0)
{
p1 = Add(p1, p1); // Double
if ((u.BitAt(high_bit)))
p1 = Add(p1, p); // Add
--high_bit;
}
return p1;
}
protected IntX MulInverse(IntX eq) => MulInverse(eq, modulo);
public static IntX MulInverse(IntX eq, IntX modulo)
{
eq = Mod(eq, modulo);
Stack<IntX> collect = new Stack<IntX>();
IntX v = modulo; // Copy modulo
IntX m;
while((m = v % eq) != 0)
{
collect.Push(-v/eq/*-(m.l_div)*/);
v = eq;
eq = m;
}
if (collect.Count == 0) return 1;
v = 1;
m = collect.Pop();
while (collect.Count > 0)
{
eq = m;
m = v + (m * collect.Pop());
v = eq;
}
return Mod(m, modulo);
}
public CurvePoint Inverse(CurvePoint p) => Inverse(p, modulo);
protected static CurvePoint Inverse(CurvePoint p, IntX modulo) => new CurvePoint(p.X, Mod(-p.Y, modulo));
public bool IsOnCurve(CurvePoint p)
{
try { CheckOnCurve(p); }
catch { return false; }
return true;
}
protected void CheckOnCurve(CurvePoint p)
{
if (
p!=CurvePoint.POINT_AT_INFINITY && // The point at infinity is asserted to be on the curve
(type == CurveType.Weierstrass && Mod(p.Y * p.Y) != Mod((p.X * p.X * p.X) + (p.X * a) + b)) || // Weierstrass formula
(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
) throw new Exception("Point is not on curve");
}
protected IntX Mod(IntX b) => Mod(b, modulo);
private static IntX Mod(IntX x, IntX m)
{
IntX r = x.Abs() > m ? x % m : x;
return r < 0 ? r + m : r;
}
protected static IntX ModPow(IntX x, IntX power, IntX prime)
{
IntX result = 1;
bool setBit = false;
while(power > 0)
{
x %= prime;
setBit = (power & 1) == 1;
power >>= 1;
if (setBit) result *= x;
x *= x;
}
return result;
}
}
}

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