/// <summary>
/// Create a Subject Public Key Info object for a given public key.
/// </summary>
/// <param name="key">One of ElGammalPublicKeyParameters, DSAPublicKeyParameter, DHPublicKeyParameters, RSAKeyParameters or ECPublicKeyParameters</param>
/// <returns>A subject public key info object.</returns>
/// <exception cref="Exception">Throw exception if object provided is not one of the above.</exception>
public static SubjectPublicKeyInfo CreateSubjectPublicKeyInfo(AsymmetricKeyParameter key)
{
if (key.isPrivate())
{
throw (new Exception("Private key passed - public key expected."));
}
if (key is ElGamalPublicKeyParameters)
{
ElGamalPublicKeyParameters _key = (ElGamalPublicKeyParameters)key;
SubjectPublicKeyInfo info =
new SubjectPublicKeyInfo(
new AlgorithmIdentifier(
OIWObjectIdentifiers.elGamalAlgorithm,
new ElGamalParameter(
_key.getParameters().getP(),
_key.getParameters().getG()
).toASN1Object()), new DERInteger(_key.getY()));
return(info);
}
if (key is DSAPublicKeyParameters)
{
DSAPublicKeyParameters _key = (DSAPublicKeyParameters)key;
SubjectPublicKeyInfo info =
new SubjectPublicKeyInfo(
new AlgorithmIdentifier(
X9ObjectIdentifiers.id_dsa,
new DSAParameter(_key.getParameters().getP(), _key.getParameters().getQ(), _key.getParameters().getG()).toASN1Object()),
new DERInteger(_key.getY())
);
return(info);
}
if (key is DHPublicKeyParameters)
{
DHPublicKeyParameters _key = (DHPublicKeyParameters)key;
SubjectPublicKeyInfo info = new SubjectPublicKeyInfo(
new AlgorithmIdentifier(X9ObjectIdentifiers.dhpublicnumber,
new DHParameter(_key.getParameters().getP(),
_key.getParameters().getG(),
_key.getParameters().getJ()).toASN1Object()), new DERInteger(_key.getY()));
return(info);
} // End of DH
if (key is RSAKeyParameters)
{
RSAKeyParameters _key = (RSAKeyParameters)key;
if (_key.isPrivate())
{
throw (new Exception("Private RSA Key provided."));
}
SubjectPublicKeyInfo info = new SubjectPublicKeyInfo(new AlgorithmIdentifier(PKCSObjectIdentifiers.rsaEncryption, new DERNull()), new RSAPublicKeyStructure(_key.getModulus(), _key.getExponent()).toASN1Object());
return(info);
} // End of RSA.
if (key is ECPublicKeyParameters)
{
ECPublicKeyParameters _key = (ECPublicKeyParameters)key;
X9ECParameters ecP = new X9ECParameters(
_key.getParameters().getCurve(),
_key.getParameters().getG(),
_key.getParameters().getN(),
_key.getParameters().getH(),
_key.getParameters().getSeed());
X962Parameters x962 = new X962Parameters(ecP);
ASN1OctetString p = (ASN1OctetString)(new X9ECPoint(_key.getQ()).toASN1Object());
SubjectPublicKeyInfo info = new SubjectPublicKeyInfo(new AlgorithmIdentifier(X9ObjectIdentifiers.id_ecPublicKey, x962.toASN1Object()), p.getOctets());
return(info);
} // End of EC
throw (new Exception("Class provided no convertable:" + key.GetType()));
}
