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CypherCore/Source/Framework/Cryptography/SRP6.cs
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2024-02-22 16:45:38 -05:00

409 lines
16 KiB
C#

// Copyright (c) CypherCore <http://github.com/CypherCore> All rights reserved.
// Licensed under the GNU GENERAL PUBLIC LICENSE. See LICENSE file in the project root for full license information.
using System;
using System.Linq;
using System.Numerics;
using System.Security.Cryptography;
using System.Text;
namespace Framework.Cryptography
{
public abstract class SRP6
{
public static int SaltLength = 32;
public byte[] s = new byte[SaltLength]; // s - the user's password salt, random, used to calculate v on registration
protected BigInteger I; // H(I) - the username, all uppercase
protected BigInteger b; // b - randomly chosen by the server, same length as N, never given out
protected BigInteger v; // v - the user's password verifier, derived from s + H(USERNAME || ":" || PASSWORD)
public BigInteger B; // B = k*v + g^b
bool _used; // a single instance can only be used to verify once
public SRP6()
{
s = new byte[0].GenerateRandomKey(SaltLength);
_used = true;
}
public SRP6(BigInteger i, byte[] salt, byte[] verifier, BigInteger N, BigInteger g, BigInteger k)
{
s = salt;
I = i;
b = CalculatePrivateB(N);
v = new BigInteger(verifier, true);
B = CalculatePublicB(N, g, k);
}
public BigInteger? VerifyClientEvidence(BigInteger A, BigInteger clientM1)
{
Cypher.Assert(!_used, "A single SRP6 object must only ever be used to verify ONCE!");
_used = true;
return DoVerifyClientEvidence(A, clientM1);
}
public bool CheckCredentials(string username, string password)
{
return v == new BigInteger(CalculateVerifier(username, password, s), true);
}
BigInteger CalculatePrivateB(BigInteger N)
{
BigInteger b = new BigInteger(new byte[0].GenerateRandomKey((int)N.GetBitLength()), true);
b %= (N - 1);
return b;
}
BigInteger CalculatePublicB(BigInteger N, BigInteger g, BigInteger k)
{
return (BigInteger.ModPow(g, b, N) + (v * k)) % N;
}
byte[] CalculateVerifier(string username, string password, byte[] salt)
{
// v = g ^ H(s || H(u || ':' || p)) mod N
return BigInteger.ModPow(Getg(), CalculateX(username, password, salt), GetN()).ToByteArray();
}
public abstract BigInteger GetN();
public abstract BigInteger Getg();
public abstract BigInteger CalculateServerEvidence(BigInteger A, BigInteger clientM1, BigInteger K);
public static (byte[], byte[]) MakeAccountRegistrationData<T>(string username, string password) where T : new()
{
GruntSRP6 impl = new();
return (impl.s, impl.CalculateVerifier(username, password, impl.s));
}
public static (byte[], byte[]) MakeBNetRegistrationData<T>(string username, string password) where T : new()
{
BnetSRP6v2Hash256 impl = new();
return (impl.s, impl.CalculateVerifier(username, password, impl.s));
}
public abstract BigInteger CalculateX(string username, string password, byte[] salt);
public abstract BigInteger? DoVerifyClientEvidence(BigInteger A, BigInteger clientM1);
}
public class GruntSRP6 : SRP6
{
static BigInteger N;// the modulus, an algorithm parameter; all operations are mod this
static BigInteger g;// a [g]enerator for the ring of integers mod N, algorithm parameter
static SHA1 _sha1 = SHA1.Create();
static GruntSRP6()
{
N = new BigInteger("894B645E89E1535BBDAD5B8B290650530801B18EBFBF5E8FAB3C82872A3E9BB7".ToByteArray(), true, true);
g = new BigInteger(7u);
}
public GruntSRP6() : base() { }
public GruntSRP6(string username, byte[] salt, byte[] verifier) : base(new BigInteger(_sha1.ComputeHash(Encoding.UTF8.GetBytes(username)), true, true), salt, verifier, N, g, 3) { }
public override BigInteger CalculateServerEvidence(BigInteger A, BigInteger clientM1, BigInteger K)
{
return new BigInteger(_sha1.ComputeHash(A.ToByteArray().Combine(clientM1.ToByteArray().Combine(K.ToByteArray()))), true, true);
}
public override BigInteger CalculateX(string username, string password, byte[] salt)
{
return new BigInteger(_sha1.ComputeHash(salt.Combine(_sha1.ComputeHash(Encoding.UTF8.GetBytes(username + ":" + password)))), true, true);
}
public override BigInteger? DoVerifyClientEvidence(BigInteger A, BigInteger clientM1)
{
if ((A % N).IsZero)
return null;
BigInteger u = new(_sha1.ComputeHash(A.ToByteArray().Combine(B.ToByteArray())), false, true);
byte[] S = BigInteger.ModPow(A * BigInteger.ModPow(v, u, N), b, N).ToByteArray();
byte[] K = SHA1Interleave(S);
// NgHash = H(N) xor H(g)
byte[] NHash = _sha1.ComputeHash(N.ToByteArray());
byte[] gHash = _sha1.ComputeHash(g.ToByteArray());
byte[] NgHash = NHash.Select((x, i) => (byte)(x ^ gHash[i])).ToArray();
BigInteger ourM = new BigInteger(_sha1.ComputeHash(NgHash.Combine(I.ToByteArray().Combine(s.Combine(A.ToByteArray().Combine(B.ToByteArray().Combine(K)))))), true, true);
if (ourM == clientM1)
return new BigInteger(K, true, true);
return null;
}
byte[] SHA1Interleave(byte[] S)
{
// split S into two buffers
byte[] buf0 = new byte[32 / 2];
byte[] buf1 = new byte[32 / 2];
for (int i = 0; i < S.Length / 2; ++i)
{
buf0[i] = S[2 * i + 0];
buf1[i] = S[2 * i + 1];
}
// find position of first nonzero byte
int p = 0;
while (p < S.Length && S[p] == 0)
++p;
if ((p & 1) != 0)
++p; // skip one extra byte if p is odd
p /= 2; // offset into buffers
// hash each of the halves, starting at the first nonzero byte
byte[] hash0 = _sha1.ComputeHash(buf0[p..].Combine(S[(S.Length / 2 - p)..]));
byte[] hash1 = _sha1.ComputeHash(buf1[p..].Combine(S[(S.Length / 2 - p)..]));
// stick the two hashes back together
byte[] K = new byte[SHA1.HashSizeInBytes * 2];
for (int i = 0; i < SHA1.HashSizeInBytes; ++i)
{
K[2 * i + 0] = hash0[i];
K[2 * i + 1] = hash1[i];
}
return K;
}
public override BigInteger GetN() { return N; }
public override BigInteger Getg() { return g; }
}
public abstract class BnetSRP6Base : SRP6
{
protected static SHA256 _sha256 = SHA256.Create();
protected static SHA512 _sha512 = SHA512.Create();
public BnetSRP6Base() : base() { }
public BnetSRP6Base(BigInteger i, byte[] salt, byte[] verifier, BigInteger N, BigInteger g, BigInteger k) : base(i, salt, verifier, N, g, k) { }
public override BigInteger CalculateServerEvidence(BigInteger A, BigInteger clientM1, BigInteger K)
{
return DoCalculateEvidence(A, clientM1, K);
}
public override BigInteger? DoVerifyClientEvidence(BigInteger A, BigInteger clientM1)
{
BigInteger N = GetN();
if ((A % N).IsZero)
return null;
BigInteger u = CalculateU(A);
if ((u % N).IsZero)
return null;
BigInteger S = BigInteger.ModPow(A * BigInteger.ModPow(v, u, N), b, N);
BigInteger ourM = DoCalculateEvidence(A, B, S);
if (ourM != clientM1)
return null;
return S;
}
byte[] GetBrokenEvidenceVector(BigInteger bn)
{
int bytes = (int)(bn.GetBitLength() + 8) >> 3;
var byteArray = bn.ToByteArray(true, true);
return new byte[bytes - byteArray.Length].Combine(byteArray);
}
public abstract byte GetVersion();
public abstract uint GetXIterations();
public virtual BigInteger CalculateU(BigInteger A) { return default; }
public virtual BigInteger DoCalculateEvidence(params BigInteger[] bns) { return default; }
public BigInteger DoCalculateEvidenceHash256(params BigInteger[] bns)
{
for (var i = 0; i < bns.Length; ++i)
{
var bytes = GetBrokenEvidenceVector(bns[i]);
if (i == bns.Length - 1)
{
_sha256.TransformFinalBlock(bytes, 0, bytes.Length);
break;
}
_sha256.TransformBlock(bytes, 0, bytes.Length, null, 0);
}
return new BigInteger(_sha256.Hash, true, true);
}
public BigInteger DoCalculateEvidenceHash512(params BigInteger[] bns)
{
for (var i = 0; i < bns.Length; ++i)
{
var bytes = GetBrokenEvidenceVector(bns[i]);
if (i == bns.Length - 1)
{
_sha512.TransformFinalBlock(bytes, 0, bytes.Length);
break;
}
_sha512.TransformBlock(bytes, 0, bytes.Length, null, 0);
}
return new BigInteger(_sha512.Hash, true, true);
}
}
public class BnetSRP6v1Base : BnetSRP6Base
{
/// <summary>
/// // the modulus, an algorithm parameter; all operations are mod this
/// </summary>
public static BigInteger N;
/// <summary>
/// // a [g]enerator for the ring of integers mod N, algorithm parameter
/// </summary>
public static BigInteger g;
protected static byte[] dummyBytes = new byte[127];
static BnetSRP6v1Base()
{
g = new BigInteger(2u);
N = new BigInteger("86A7F6DEEB306CE519770FE37D556F29944132554DED0BD68205E27F3231FEF5A10108238A3150C59CAF7B0B6478691C13A6ACF5E1B5ADAFD4A943D4A21A142B800E8A55F8BFBAC700EB77A7235EE5A609E350EA9FC19F10D921C2FA832E4461B7125D38D254A0BE873DFC27858ACB3F8B9F258461E4373BC3A6C2A9634324AB".ToByteArray(), true, true);
}
public BnetSRP6v1Base() : base() { }
public BnetSRP6v1Base(string username, byte[] salt, byte[] verifier, BigInteger k) : base(new BigInteger(SHA256.HashData(Encoding.UTF8.GetBytes(username)), true), salt, verifier, N, g, k) { }
public override BigInteger CalculateX(string username, string password, byte[] salt)
{
return new BigInteger(SHA256.HashData(salt.Combine(SHA256.HashData(Encoding.UTF8.GetBytes(username + ":" + password)))), true);
}
public override BigInteger GetN() { return N; }
public override BigInteger Getg() { return g; }
public override byte GetVersion() { return 1; }
public override uint GetXIterations() { return 1; }
}
public class BnetSRP6v2Base : BnetSRP6Base
{
/// <summary>
/// // the modulus, an algorithm parameter; all operations are mod this
/// </summary>
protected static BigInteger N;
/// <summary>
/// // a [g]enerator for the ring of integers mod N, algorithm parameter
/// </summary>
protected static BigInteger g;
protected static byte[] dummyBytes = new byte[255];
static BnetSRP6v2Base()
{
N = new BigInteger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oByteArray(), true, true);
g = new BigInteger(2u);
}
public BnetSRP6v2Base() : base() { }
public BnetSRP6v2Base(string username, byte[] salt, byte[] verifier, BigInteger k) : base(new BigInteger(SHA256.HashData(Encoding.UTF8.GetBytes(username)), true), salt, verifier, N, g, k) { }
public override BigInteger CalculateX(string username, string password, byte[] salt)
{
string tmp = username + ":" + password;
Rfc2898DeriveBytes rfc = new Rfc2898DeriveBytes(tmp, salt, (int)GetXIterations(), HashAlgorithmName.SHA512);
byte[] xBytes = rfc.GetBytes(SHA512.HashSizeInBytes);
BigInteger x = new(xBytes, true, true);
if ((xBytes[0] & 0x80) != 0)
{
byte[] fix = new byte[65];
fix[64] = 1;
x -= new BigInteger(fix, true);
}
return x % (N - 1);
}
public override BigInteger GetN() { return N; }
public override BigInteger Getg() { return g; }
public override byte GetVersion() { return 2; }
public override uint GetXIterations() { return 15000; }
}
public class BnetSRP6v1Hash256 : BnetSRP6v1Base
{
public BnetSRP6v1Hash256() : base() { }
public BnetSRP6v1Hash256(string username, byte[] salt, byte[] verifier) : base(username, salt, verifier, new BigInteger(SHA256.HashData(N.ToByteArray(true, true).Combine(dummyBytes.Combine(g.ToByteArray(true, true)))), true, true)) { }
public override BigInteger CalculateU(BigInteger A)
{
return new BigInteger(SHA256.HashData(A.ToByteArray(true, true).Combine(B.ToByteArray(true, true))), true, true);
}
public override BigInteger DoCalculateEvidence(params BigInteger[] bns)
{
return DoCalculateEvidenceHash256(bns);
}
}
public class BnetSRP6v1Hash512 : BnetSRP6v1Base
{
public BnetSRP6v1Hash512() : base() { }
public BnetSRP6v1Hash512(string username, byte[] salt, byte[] verifier) : base(username, salt, verifier, new BigInteger(SHA512.HashData(N.ToByteArray(true, true).Combine(dummyBytes.Combine(g.ToByteArray(true, true)))), true, true)) { }
public override BigInteger CalculateU(BigInteger A)
{
return new BigInteger(_sha512.ComputeHash(A.ToByteArray(true, true).Combine(B.ToByteArray(true, true))), true, true);
}
public override BigInteger DoCalculateEvidence(params BigInteger[] bns)
{
return DoCalculateEvidenceHash512(bns);
}
}
public class BnetSRP6v2Hash256 : BnetSRP6v2Base
{
public BnetSRP6v2Hash256() : base() { }
public BnetSRP6v2Hash256(string username, byte[] salt, byte[] verifier) : base(username, salt, verifier, new BigInteger(SHA256.HashData(N.ToByteArray(true, true).Combine(dummyBytes.Combine(g.ToByteArray(true, true)))), true, true)) { }
public override BigInteger CalculateU(BigInteger A)
{
return new BigInteger(SHA256.HashData(A.ToByteArray(true, true).Combine(B.ToByteArray(true, true))), true, true);
}
public override BigInteger DoCalculateEvidence(params BigInteger[] bns)
{
return DoCalculateEvidenceHash256(bns);
}
}
public class BnetSRP6v2Hash512 : BnetSRP6v2Base
{
public BnetSRP6v2Hash512() : base() { }
public BnetSRP6v2Hash512(string username, byte[] salt, byte[] verifier) : base(username, salt, verifier, new BigInteger(SHA512.HashData(N.ToByteArray(true, true).Combine(g.ToByteArray(true, true))), true, true)) { }
public override BigInteger CalculateU(BigInteger A)
{
return new BigInteger(SHA512.HashData(A.ToByteArray(true, true).Combine(B.ToByteArray(true, true))), true, true);
}
public override BigInteger DoCalculateEvidence(params BigInteger[] bns)
{
return DoCalculateEvidenceHash512(bns);
}
}
}