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using System;
using System.Collections;
using System.IO;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Math.EC;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.IO;
namespace Org.BouncyCastle.Crypto.Tls
{
/// <summary>(D)TLS ECDHE key exchange (see RFC 4492).</summary>
public class TlsECDheKeyExchange
: TlsECDHKeyExchange
{
protected TlsSignerCredentials mServerCredentials = null;
public TlsECDheKeyExchange(int keyExchange, IList supportedSignatureAlgorithms, int[] namedCurves,
byte[] clientECPointFormats, byte[] serverECPointFormats)
: base(keyExchange, supportedSignatureAlgorithms, namedCurves, clientECPointFormats, serverECPointFormats)
{
}
public override void ProcessServerCredentials(TlsCredentials serverCredentials)
{
if (!(serverCredentials is TlsSignerCredentials))
throw new TlsFatalAlert(AlertDescription.internal_error);
ProcessServerCertificate(serverCredentials.Certificate);
this.mServerCredentials = (TlsSignerCredentials)serverCredentials;
}
public override byte[] GenerateServerKeyExchange()
{
DigestInputBuffer buf = new DigestInputBuffer();
this.mECAgreePrivateKey = TlsEccUtilities.GenerateEphemeralServerKeyExchange(mContext.SecureRandom, mNamedCurves,
mClientECPointFormats, buf);
/*
* RFC 5246 4.7. digitally-signed element needs SignatureAndHashAlgorithm from TLS 1.2
*/
SignatureAndHashAlgorithm signatureAndHashAlgorithm = TlsUtilities.GetSignatureAndHashAlgorithm(
mContext, mServerCredentials);
IDigest d = TlsUtilities.CreateHash(signatureAndHashAlgorithm);
SecurityParameters securityParameters = mContext.SecurityParameters;
d.BlockUpdate(securityParameters.clientRandom, 0, securityParameters.clientRandom.Length);
d.BlockUpdate(securityParameters.serverRandom, 0, securityParameters.serverRandom.Length);
buf.UpdateDigest(d);
byte[] hash = DigestUtilities.DoFinal(d);
byte[] signature = mServerCredentials.GenerateCertificateSignature(hash);
DigitallySigned signed_params = new DigitallySigned(signatureAndHashAlgorithm, signature);
signed_params.Encode(buf);
return buf.ToArray();
}
public override void ProcessServerKeyExchange(Stream input)
{
SecurityParameters securityParameters = mContext.SecurityParameters;
SignerInputBuffer buf = new SignerInputBuffer();
Stream teeIn = new TeeInputStream(input, buf);
ECDomainParameters curve_params = TlsEccUtilities.ReadECParameters(mNamedCurves, mClientECPointFormats, teeIn);
byte[] point = TlsUtilities.ReadOpaque8(teeIn);
DigitallySigned signed_params = DigitallySigned.Parse(mContext, input);
ISigner signer = InitVerifyer(mTlsSigner, signed_params.Algorithm, securityParameters);
buf.UpdateSigner(signer);
if (!signer.VerifySignature(signed_params.Signature))
throw new TlsFatalAlert(AlertDescription.decrypt_error);
this.mECAgreePublicKey = TlsEccUtilities.ValidateECPublicKey(TlsEccUtilities.DeserializeECPublicKey(
mClientECPointFormats, curve_params, point));
}
public override void ValidateCertificateRequest(CertificateRequest certificateRequest)
{
/*
* RFC 4492 3. [...] The ECDSA_fixed_ECDH and RSA_fixed_ECDH mechanisms are usable with
* ECDH_ECDSA and ECDH_RSA. Their use with ECDHE_ECDSA and ECDHE_RSA is prohibited because
* the use of a long-term ECDH client key would jeopardize the forward secrecy property of
* these algorithms.
*/
byte[] types = certificateRequest.CertificateTypes;
for (int i = 0; i < types.Length; ++i)
{
switch (types[i])
{
case ClientCertificateType.rsa_sign:
case ClientCertificateType.dss_sign:
case ClientCertificateType.ecdsa_sign:
break;
default:
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
}
}
public override void ProcessClientCredentials(TlsCredentials clientCredentials)
{
if (clientCredentials is TlsSignerCredentials)
{
// OK
}
else
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
}
protected virtual ISigner InitVerifyer(TlsSigner tlsSigner, SignatureAndHashAlgorithm algorithm,
SecurityParameters securityParameters)
{
ISigner signer = tlsSigner.CreateVerifyer(algorithm, this.mServerPublicKey);
signer.BlockUpdate(securityParameters.clientRandom, 0, securityParameters.clientRandom.Length);
signer.BlockUpdate(securityParameters.serverRandom, 0, securityParameters.serverRandom.Length);
return signer;
}
}
}
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