public byte[] CalculateCommonSecret(EthECKey publicKey)
{
var agreement = new ECDHBasicAgreement();
agreement.Init(_ecKey.PrivateKey);
var z = agreement.CalculateAgreement(publicKey._ecKey.GetPublicKeyParameters());
return BigIntegers.AsUnsignedByteArray(agreement.GetFieldSize(), z);
}
public static byte[] CalculateECDHBasicAgreement(ECPublicKeyParameters publicKey, ECPrivateKeyParameters privateKey)
{
ECDHBasicAgreement eCDHBasicAgreement = new ECDHBasicAgreement();
eCDHBasicAgreement.Init(privateKey);
BigInteger n = eCDHBasicAgreement.CalculateAgreement(publicKey);
return(BigIntegers.AsUnsignedByteArray(eCDHBasicAgreement.GetFieldSize(), n));
}
/// <summary>
/// Creates symmetric key from sender's public key and own key pair
/// </summary>
/// <param name="publicKeyBytes"></param>
/// <returns></returns>
protected byte[] GetSymmetricKey(byte[] publicKeyBytes)
{
ECPublicKeyParameters publicKey = new ECPublicKeyParameters(X9.Curve.DecodePoint(publicKeyBytes), EcSpec);
var agree = new ECDHBasicAgreement();
agree.Init(KeyPair.Private);
BigInteger z = agree.CalculateAgreement((AsymmetricKeyParameter)publicKey);
return(BigIntegers.AsUnsignedByteArray(agree.GetFieldSize(), z));
}
public string GenerateSharedSecretHex(string pubKeyHex)
{
var pubKeyBytes = pubKeyHex.HexToByteArray();
var q = _curve.Curve.DecodePoint(pubKeyBytes);
var remotePublicKey = new ECPublicKeyParameters("ECDH", q, _domain);
var agreement = new ECDHBasicAgreement();
agreement.Init(_key.Private);
var basicAgreementResult = agreement.CalculateAgreement(remotePublicKey);
return(BigIntegers.AsUnsignedByteArray(agreement.GetFieldSize(), basicAgreementResult).ToHex(true));
}
public static byte[] CalculateECDHBasicAgreement(ECPublicKeyParameters publicKey, ECPrivateKeyParameters privateKey)
{
ECDHBasicAgreement basicAgreement = new ECDHBasicAgreement();
basicAgreement.Init(privateKey);
BigInteger agreementValue = basicAgreement.CalculateAgreement(publicKey);
/*
* RFC 4492 5.10. Note that this octet string (Z in IEEE 1363 terminology) as output by
* FE2OSP, the Field Element to Octet String Conversion Primitive, has constant length for
* any given field; leading zeros found in this octet string MUST NOT be truncated.
*/
return(BigIntegers.AsUnsignedByteArray(basicAgreement.GetFieldSize(), agreementValue));
}
public string GenerateSharedSecretHex(string pubKeyHex)
{
var encoded = pubKeyHex.HexToByteArray();
if (encoded.Length == 64)
{
var numArray = new byte[encoded.Length + 1];
numArray[0] = (byte)4;
Array.Copy((Array)encoded, 0, (Array)numArray, 1, encoded.Length);
encoded = numArray;
}
var publicKeyParameters = new ECPublicKeyParameters("ECDH", ECDH_Key._curve.Curve.DecodePoint(encoded), ECDH_Key._domain);
var ecdhBasicAgreement = new ECDHBasicAgreement();
ecdhBasicAgreement.Init(_key.Private);
return(BigIntegers.AsUnsignedByteArray(ecdhBasicAgreement.GetFieldSize(), ecdhBasicAgreement.CalculateAgreement((ICipherParameters)publicKeyParameters)).ToHex(true));
}
