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); } }