public PublicKey getPublicKey(PGPPublicKey publicKey) throws PGPException {
KeyFactory fact;
PublicKeyPacket publicPk = publicKey.getPublicKeyPacket();
try {
switch (publicPk.getAlgorithm()) {
case PublicKeyAlgorithmTags.RSA_ENCRYPT:
case PublicKeyAlgorithmTags.RSA_GENERAL:
case PublicKeyAlgorithmTags.RSA_SIGN:
RSAPublicBCPGKey rsaK = (RSAPublicBCPGKey) publicPk.getKey();
RSAPublicKeySpec rsaSpec =
new RSAPublicKeySpec(rsaK.getModulus(), rsaK.getPublicExponent());
fact = helper.createKeyFactory("RSA");
return fact.generatePublic(rsaSpec);
case PublicKeyAlgorithmTags.DSA:
DSAPublicBCPGKey dsaK = (DSAPublicBCPGKey) publicPk.getKey();
DSAPublicKeySpec dsaSpec =
new DSAPublicKeySpec(dsaK.getY(), dsaK.getP(), dsaK.getQ(), dsaK.getG());
fact = helper.createKeyFactory("DSA");
return fact.generatePublic(dsaSpec);
case PublicKeyAlgorithmTags.ELGAMAL_ENCRYPT:
case PublicKeyAlgorithmTags.ELGAMAL_GENERAL:
ElGamalPublicBCPGKey elK = (ElGamalPublicBCPGKey) publicPk.getKey();
ElGamalPublicKeySpec elSpec =
new ElGamalPublicKeySpec(
elK.getY(), new ElGamalParameterSpec(elK.getP(), elK.getG()));
fact = helper.createKeyFactory("ElGamal");
return fact.generatePublic(elSpec);
default:
throw new PGPException("unknown public key algorithm encountered");
}
} catch (PGPException e) {
throw e;
} catch (Exception e) {
throw new PGPException("exception constructing public key", e);
}
}
