Convert SSL .pem to .p12 with or without OpenSSL

Question

I get external .pem files that need to be converted to .p12 files - I add a username and password in the process. (I need to do this to utilize a thir

Answer 1

Based on @MugglesMerriweather 's answer, an updated version to v1.51 is the following:

public static byte[] convertPEMToPKCS12(final String keyFile, final String cerFile,
        final String password)
        throws IOException, CertificateException, KeyStoreException, NoSuchAlgorithmException
    {
        // Get the private key
        FileReader reader = new FileReader(keyFile);

        PEMParser pem = new PEMParser(reader);
        PEMKeyPair pemKeyPair = ((PEMKeyPair)pem.readObject());
        JcaPEMKeyConverter jcaPEMKeyConverter = new JcaPEMKeyConverter().setProvider("SC");
        KeyPair keyPair = jcaPEMKeyConverter.getKeyPair(pemKeyPair);

        PrivateKey key = keyPair.getPrivate();

        pem.close();
        reader.close();

        // Get the certificate
        reader = new FileReader(cerFile);
        pem = new PEMParser(reader);

        X509CertificateHolder certHolder = (X509CertificateHolder) pem.readObject();
        java.security.cert.Certificate X509Certificate =
            new JcaX509CertificateConverter().setProvider("SC")
                .getCertificate(certHolder);

        pem.close();
        reader.close();

        // Put them into a PKCS12 keystore and write it to a byte[]
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        KeyStore ks = KeyStore.getInstance("PKCS12");
        ks.load(null);
        ks.setKeyEntry("alias", (Key) key, password.toCharArray(),
            new java.security.cert.Certificate[]{X509Certificate});
        ks.store(bos, password.toCharArray());
        bos.close();
        return bos.toByteArray();
    }