Question

Implementing org.jscep.server.ScepServlet I need to provide an implementation for the method doEnroll ( List<X509Certificate> doEnroll(CertificationRequest certificationRequest) ).

How do I get from the provided CertificationRequest to return a X509Certificate?

Besides the CertificationRequest I also have the certificate I need to use for signing

It will suffice with a way to get the public key from the certification request, since I have the rest of the code for generating the certificate.

What I have up till now:

protected List<X509Certificate> doEnroll(CertificationRequest certificationRequest) throws OperationFailureException, Exception {
    CaCertificate caCertificate = getSelfSignedCertificate();
    X509V3CertificateGenerator certGen = new X509V3CertificateGenerator();
    certGen.setSerialNumber(BigInteger.valueOf(System.currentTimeMillis()));
    certGen.setIssuerDN(caCertificate.getCertificate().getSubjectX500Principal());
    certGen.setNotBefore(notBefore);
    certGen.setNotAfter(notAfter);
    certGen.setSubjectDN(certificationRequest.getCertificationRequestInfo().getSubject());
    certGen.setPublicKey(publicKey); // this is basically what I need

    X509Certificate issuedCert = certGen.generate(caCertificate.getKeypair().getPrivate());

    List<X509Certificate> x509Certificates = new ArrayList<X509Certificate>();
    x509Certificates.add(issuedCert);

    return x509Certificates;
}

Answer 1

Found this method in an jscep test class:

public static PublicKey getPublicKey(CertificationRequest csr) throws IOException {
    SubjectPublicKeyInfo pubKeyInfo = csr.getCertificationRequestInfo().getSubjectPublicKeyInfo();
    RSAKeyParameters keyParams = (RSAKeyParameters) PublicKeyFactory.createKey(pubKeyInfo);
    KeySpec keySpec = new RSAPublicKeySpec(keyParams.getModulus(), keyParams.getExponent());

    try {
        KeyFactory kf = KeyFactory.getInstance("RSA");
        return kf.generatePublic(keySpec);
    } catch (Exception e) {
        throw new IOException(e);
    }
}