/// <summary>
/// Exports the key used by the ECC object into an <see cref="ECParameters"/> object.
/// If the key was created as a named curve, the Curve property will contain named curve parameters
/// otherwise it will contain explicit parameters.
/// </summary>
/// <exception cref="CryptographicException">
/// if there was an issue obtaining the curve values.
/// </exception>
/// <returns>The key and named curve parameters used by the ECC object.</returns>
public override ECParameters ExportParameters()
{
if (string.IsNullOrEmpty(_curveName))
{
return(ExportExplicitParameters());
}
else
{
ECParameters ecparams = new ECParameters();
ECCng.ExportNamedCurveParameters(ref ecparams, _keyBlob, includePrivateParameters: false);
ecparams.Curve = ECCurve.CreateFromFriendlyName(_curveName);
return(ecparams);
}
}
internal static ECParameters ExportNamedCurveParameters(CngKey key, bool includePrivateParameters)
{
byte[] ecBlob = ExportKeyBlob(key, includePrivateParameters);
// We now have a buffer laid out as follows:
// BCRYPT_ECCKEY_BLOB header
// byte[cbKey] Q.X
// byte[cbKey] Q.Y
// -- Private only --
// byte[cbKey] D
ECParameters ecParams = new ECParameters();
KeyBlobMagicNumber magic = (KeyBlobMagicNumber)BitConverter.ToInt32(ecBlob, 0);
// Check the magic value in the key blob header. If the blob does not have the required magic,
// then throw a CryptographicException.
CheckMagicValueOfKey(magic, includePrivateParameters);
unsafe
{
// Fail-fast if a rogue provider gave us a blob that isn't even the size of the blob header.
if (ecBlob.Length < sizeof(BCRYPT_ECCKEY_BLOB))
throw ErrorCode.E_FAIL.ToCryptographicException();
fixed(byte *pEcBlob = ecBlob)
{
BCRYPT_ECCKEY_BLOB *pBcryptBlob = (BCRYPT_ECCKEY_BLOB *)pEcBlob;
int offset = sizeof(BCRYPT_ECCKEY_BLOB);
ecParams.Q = new ECPoint
{
X = Interop.BCrypt.Consume(ecBlob, ref offset, pBcryptBlob->cbKey),
Y = Interop.BCrypt.Consume(ecBlob, ref offset, pBcryptBlob->cbKey)
};
if (includePrivateParameters)
{
ecParams.D = Interop.BCrypt.Consume(ecBlob, ref offset, pBcryptBlob->cbKey);
}
}
}
ecParams.Curve = ECCurve.CreateFromFriendlyName(key.GetCurveName());
return(ecParams);
}
private static ECParameters ExportNamedCurveParameters(SafeEcKeyHandle key, string curveName, bool includePrivateParameters)
{
CheckInvalidKey(key);
ECParameters parameters = Interop.AndroidCrypto.GetECKeyParameters(key, includePrivateParameters);
bool hasPrivateKey = (parameters.D != null);
if (hasPrivateKey != includePrivateParameters)
{
throw new CryptographicException(SR.Cryptography_CSP_NoPrivateKey);
}
// Assign Curve
parameters.Curve = ECCurve.CreateFromFriendlyName(curveName);
return(parameters);
}
/// <summary>
/// Exports the key used by the ECC object into an <see cref="ECParameters"/> object.
/// If the key was created as a named curve, the Curve property will contain named curve parameters
/// otherwise it will contain explicit parameters.
/// </summary>
/// <exception cref="CryptographicException">
/// if there was an issue obtaining the curve values.
/// </exception>
/// <returns>The key and named curve parameters used by the ECC object.</returns>
public override ECParameters ExportParameters()
{
if (_keyBlob == null)
{
throw new ObjectDisposedException(nameof(ECDiffieHellmanPublicKey));
}
if (string.IsNullOrEmpty(_curveName))
{
return(ExportExplicitParameters());
}
else
{
ECParameters ecparams = new ECParameters();
ECCng.ExportNamedCurveParameters(ref ecparams, _keyBlob, includePrivateParameters: false);
ecparams.Curve = ECCurve.CreateFromFriendlyName(_curveName);
return(ecparams);
}
}
internal static void ExportParameters(
CngKey key,
bool includePrivateParameters,
ref ECParameters ecparams)
{
string curveName = key.GetCurveName();
if (string.IsNullOrEmpty(curveName))
{
byte[] fullKeyBlob = ECCng.ExportFullKeyBlob(key, includePrivateParameters);
ECCng.ExportPrimeCurveParameters(ref ecparams, fullKeyBlob, includePrivateParameters);
}
else
{
byte[] keyBlob = ECCng.ExportKeyBlob(key, includePrivateParameters);
ECCng.ExportNamedCurveParameters(ref ecparams, keyBlob, includePrivateParameters);
ecparams.Curve = ECCurve.CreateFromFriendlyName(curveName);
}
}
/// <summary>
/// Exports the key used by the ECC object into an <see cref="ECParameters"/> object.
/// If the key was created as a named curve, the Curve property will contain named curve parameters
/// otherwise it will contain explicit parameters.
/// </summary>
/// <exception cref="CryptographicException">
/// if there was an issue obtaining the curve values.
/// </exception>
/// <returns>The key and named curve parameters used by the ECC object.</returns>
public override ECParameters ExportParameters()
{
using (CngKey key = Import())
{
ECParameters ecparams = default;
string? curveName = key.GetCurveName(out _);
if (string.IsNullOrEmpty(curveName))
{
byte[] fullKeyBlob = ECCng.ExportFullKeyBlob(key, includePrivateParameters: false);
ECCng.ExportPrimeCurveParameters(ref ecparams, fullKeyBlob, includePrivateParameters: false);
}
else
{
byte[] keyBlob = ECCng.ExportKeyBlob(key, includePrivateParameters: false);
ECCng.ExportNamedCurveParameters(ref ecparams, keyBlob, includePrivateParameters: false);
ecparams.Curve = ECCurve.CreateFromFriendlyName(curveName);
}
return(ecparams);
}
}
