ECDHCBasicAgreement
class ECDHCBasicAgreement
using Renci.SshNet.Security.Org.BouncyCastle.Crypto.Parameters;
using Renci.SshNet.Security.Org.BouncyCastle.Math;
using Renci.SshNet.Security.Org.BouncyCastle.Math.EC;
using System;
namespace Renci.SshNet.Security.Org.BouncyCastle.Crypto.Agreement
{
internal class ECDHCBasicAgreement
{
private ECPrivateKeyParameters privKey;
public virtual void Init(AsymmetricKeyParameter parameters)
{
privKey = (ECPrivateKeyParameters)parameters;
}
public virtual int GetFieldSize()
{
return (privKey.Parameters.Curve.FieldSize + 7) / 8;
}
public virtual BigInteger CalculateAgreement(ECPublicKeyParameters pubKey)
{
ECDomainParameters parameters = privKey.Parameters;
if (!parameters.Equals(pubKey.Parameters))
throw new InvalidOperationException("ECDHC public key has wrong domain parameters");
BigInteger b = parameters.H.Multiply(privKey.D).Mod(parameters.N);
ECPoint eCPoint = ECAlgorithms.CleanPoint(parameters.Curve, pubKey.Q);
if (eCPoint.IsInfinity)
throw new InvalidOperationException("Infinity is not a valid public key for ECDHC");
ECPoint eCPoint2 = eCPoint.Multiply(b).Normalize();
if (eCPoint2.IsInfinity)
throw new InvalidOperationException("Infinity is not a valid agreement value for ECDHC");
return eCPoint2.AffineXCoord.ToBigInteger();
}
}
}