public void String2Key_128_0()
{
var key = new byte[128];
var result = PKInitString2Key.String2Key(key, 32);
var expected = new byte[]
{
0xac, 0xf7, 0x70, 0x7c, 0x08, 0x97, 0x3d, 0xdf, 0xdb, 0x27, 0xcd, 0x36, 0x14, 0x42, 0xcc, 0xfb,
0xa3, 0x55, 0xc8, 0x88, 0x4c, 0xb4, 0x72, 0xf3, 0x7d, 0xa6, 0x36, 0xd0, 0x7d, 0x56, 0x78, 0x7e
};
Assert.IsTrue(result.Span.SequenceEqual(expected));
}
public void String2Key_256_0()
{
var key = new byte[256];
var result = PKInitString2Key.String2Key(key, 32);
var expected = new byte[]
{
0x5e, 0xe5, 0x0d, 0x67, 0x5c, 0x80, 0x9f, 0xe5, 0x9e, 0x4a, 0x77, 0x62, 0xc5, 0x4b, 0x65, 0x83,
0x75, 0x47, 0xea, 0xfb, 0x15, 0x9b, 0xd8, 0xcd, 0xc7, 0x5f, 0xfc, 0xa5, 0x91, 0x1e, 0x4c, 0x41
};
Assert.IsTrue(result.Span.SequenceEqual(expected));
}
public void String2Key_128_IncrementingSequence_Len_77()
{
var key = new byte[]
{
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
0x0f, 0x10, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d,
0x0e, 0x0f, 0x10, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c,
0x0d, 0x0e, 0x0f, 0x10, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08
};
var result = PKInitString2Key.String2Key(key, 32);
var expected = new byte[]
{
0x00, 0x53, 0x95, 0x3b, 0x84, 0xc8, 0x96, 0xf4, 0xeb, 0x38, 0x5c, 0x3f, 0x2e, 0x75, 0x1c, 0x4a,
0x59, 0x0e, 0xd6, 0xff, 0xad, 0xca, 0x6f, 0xf6, 0x4f, 0x47, 0xeb, 0xeb, 0x8d, 0x78, 0x0f, 0xfc
};
Assert.IsTrue(result.Span.SequenceEqual(expected));
}
private ReadOnlyMemory <byte> DeriveDHKeyAgreement(KrbKdcRep kdcRep, KrbPaPkAsRep pkRep)
{
var dhKeyInfo = ValidateDHReply(pkRep);
var kdcPublicKey = DiffieHellmanKey.ParsePublicKey(dhKeyInfo.SubjectPublicKey, agreement.PublicKey.KeyLength);
agreement.ImportPartnerKey(kdcPublicKey);
var derivedKey = agreement.GenerateAgreement();
ReadOnlySpan <byte> serverDHNonce = default;
if (pkRep.DHInfo.ServerDHNonce.HasValue)
{
serverDHNonce = pkRep.DHInfo.ServerDHNonce.Value.Span;
}
var transform = CryptoService.CreateTransform(kdcRep.EncPart.EType);
return(PKInitString2Key.String2Key(derivedKey.Span, transform.KeySize, clientDHNonce.Span, serverDHNonce));
}
public override async Task <KrbPaData> Validate(KrbKdcReq asReq, PreAuthenticationContext preauth)
{
var paPk = asReq.PaData.FirstOrDefault(p => p.Type == PaDataType.PA_PK_AS_REQ);
if (paPk == null)
{
return(null);
}
var pkreq = KrbPaPkAsReq.Decode(paPk.Value);
var authPack = await ValidateAuthPack(preauth.Principal, pkreq);
ValidateAuthenticator(authPack.PKAuthenticator, asReq.Body);
var requestAlg = authPack.ClientPublicValue?.Algorithm?.Algorithm;
IKeyAgreement agreement;
if (requestAlg?.Value == EllipticCurveDiffieHellman.Value)
{
agreement = FromEllipticCurveDomainParameters(authPack.ClientPublicValue);
}
else if (requestAlg?.Value == DiffieHellman.Value)
{
agreement = await FromDiffieHellmanDomainParametersAsync(authPack.ClientPublicValue);
}
else
{
throw OnlyKeyAgreementSupportedException();
}
var derivedKey = agreement.GenerateAgreement();
var etype = asReq.Body.EType.First();
var transform = CryptoService.CreateTransform(etype);
ReadOnlyMemory <byte> clientDHNonce = authPack.ClientDHNonce.GetValueOrDefault();
ReadOnlyMemory <byte> serverDHNonce = default;
if (clientDHNonce.Length > 0)
{
serverDHNonce = transform.GenerateRandomBytes(agreement.PublicKey.KeyLength);
await Service.Principals.CacheKey(agreement.PrivateKey);
}
var keyInfo = new KrbKdcDHKeyInfo {
SubjectPublicKey = agreement.PublicKey.EncodePublicKey()
};
if (agreement.PublicKey.CacheExpiry.HasValue)
{
keyInfo.DHKeyExpiration = agreement.PublicKey.CacheExpiry;
keyInfo.Nonce = authPack.PKAuthenticator.Nonce;
}
var sessionKey = PKInitString2Key.String2Key(
derivedKey.Span,
transform.KeySize,
clientDHNonce.Span,
serverDHNonce.Span
);
var paPkRep = new KrbPaPkAsRep
{
DHInfo = new KrbDHReplyInfo
{
DHSignedData = await SignDHResponseAsync(keyInfo),
ServerDHNonce = serverDHNonce
}
};
preauth.PaData = new[]
{
new KrbPaData
{
Type = PaDataType.PA_PK_AS_REP,
Value = paPkRep.Encode()
}
};
preauth.EncryptedPartKey = new KerberosKey(key: sessionKey.ToArray(), etype: etype);
return(null);
}
public override KrbPaData Validate(KrbKdcReq asReq, PreAuthenticationContext preauth)
{
if (asReq == null)
{
throw new ArgumentNullException(nameof(asReq));
}
if (preauth == null)
{
throw new ArgumentNullException(nameof(preauth));
}
if (!preauth.PreAuthenticationState.TryGetValue(PaDataType.PA_PK_AS_REQ, out PaDataState paState) ||
!(paState is PkInitState state))
{
return(null);
}
var authPack = ValidateAuthPack(preauth, state);
this.ValidateAuthenticator(authPack.PKAuthenticator, asReq.Body);
var requestAlg = authPack.ClientPublicValue?.Algorithm?.Algorithm;
IKeyAgreement agreement;
if (requestAlg?.Value == EllipticCurveDiffieHellman.Value)
{
agreement = this.FromEllipticCurveDomainParameters(authPack.ClientPublicValue);
}
else if (requestAlg?.Value == DiffieHellman.Value)
{
agreement = this.FromDiffieHellmanDomainParameters(authPack.ClientPublicValue);
}
else
{
throw OnlyKeyAgreementSupportedException();
}
var derivedKey = agreement.GenerateAgreement();
var preferredEType = GetPreferredEType(
asReq.Body.EType,
this.Service.Configuration.Defaults.PermittedEncryptionTypes,
this.Service.Configuration.Defaults.AllowWeakCrypto
);
if (preferredEType is null)
{
throw new InvalidOperationException("Cannot find a common EType");
}
var etype = preferredEType.Value;
var transform = CryptoService.CreateTransform(etype);
ReadOnlyMemory <byte> clientDHNonce = authPack.ClientDHNonce.GetValueOrDefault();
ReadOnlyMemory <byte> serverDHNonce = default;
if (clientDHNonce.Length > 0)
{
serverDHNonce = transform.GenerateRandomBytes(agreement.PublicKey.KeyLength);
this.Service.Principals.CacheKey(agreement.PrivateKey);
}
var keyInfo = new KrbKdcDHKeyInfo {
SubjectPublicKey = agreement.PublicKey.EncodePublicKey()
};
if (agreement.PublicKey.CacheExpiry.HasValue)
{
keyInfo.DHKeyExpiration = agreement.PublicKey.CacheExpiry;
keyInfo.Nonce = authPack.PKAuthenticator.Nonce;
}
var sessionKey = PKInitString2Key.String2Key(
derivedKey.Span,
transform.KeySize,
clientDHNonce.Span,
serverDHNonce.Span
);
var paPkRep = new KrbPaPkAsRep
{
DHInfo = new KrbDHReplyInfo
{
DHSignedData = this.SignDHResponse(keyInfo),
ServerDHNonce = serverDHNonce
}
};
preauth.PaData = new[]
{
new KrbPaData
{
Type = PaDataType.PA_PK_AS_REP,
Value = paPkRep.Encode()
}
};
preauth.EncryptedPartKey = new KerberosKey(key: sessionKey.ToArray(), etype: etype);
preauth.ClientAuthority = PaDataType.PA_PK_AS_REQ;
return(null);
}
