Self signed X509 Certificate with Bouncy Castle in Java

Question

I need to create a self signed X509 Certificate with Bouncy Castle in Java, but every class I try to include is deprecated. How can I solve this? Is there some other class

Answer 1

BEWARE: This answer uses an old version of the library with 11 CVEs.

Here's what i'm using (with BouncyCastle v1.38):

import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.Security;
import java.security.SignatureException;
import java.util.Date;

import javax.security.auth.x500.X500Principal;

import java.security.cert.CertificateEncodingException;
import java.security.cert.X509Certificate;

import org.bouncycastle.asn1.x509.ExtendedKeyUsage;
import org.bouncycastle.asn1.x509.KeyPurposeId;
import org.bouncycastle.asn1.x509.X509Extensions;
import org.bouncycastle.asn1.x509.X509Name;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.x509.X509V3CertificateGenerator;

public class BouncyCastle {

    public static void main(String[] args) throws CertificateEncodingException, InvalidKeyException, IllegalStateException, NoSuchProviderException, NoSuchAlgorithmException, SignatureException {
        X509Certificate selfSignedX509Certificate = new BouncyCastle().generateSelfSignedX509Certificate();
        System.out.println(selfSignedX509Certificate);
    }

    public X509Certificate generateSelfSignedX509Certificate() throws CertificateEncodingException, InvalidKeyException, IllegalStateException,
            NoSuchProviderException, NoSuchAlgorithmException, SignatureException {
        addBouncyCastleAsSecurityProvider();

        // generate a key pair
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA", "BC");
        keyPairGenerator.initialize(4096, new SecureRandom());
        KeyPair keyPair = keyPairGenerator.generateKeyPair();

        // build a certificate generator
        X509V3CertificateGenerator certGen = new X509V3CertificateGenerator();
        X500Principal dnName = new X500Principal("cn=example");

        // add some options
        certGen.setSerialNumber(BigInteger.valueOf(System.currentTimeMillis()));
        certGen.setSubjectDN(new X509Name("dc=name"));
        certGen.setIssuerDN(dnName); // use the same
        // yesterday
        certGen.setNotBefore(new Date(System.currentTimeMillis() - 24 * 60 * 60 * 1000));
        // in 2 years
        certGen.setNotAfter(new Date(System.currentTimeMillis() + 2 * 365 * 24 * 60 * 60 * 1000));
        certGen.setPublicKey(keyPair.getPublic());
        certGen.setSignatureAlgorithm("SHA256WithRSAEncryption");
        certGen.addExtension(X509Extensions.ExtendedKeyUsage, true,
                new ExtendedKeyUsage(KeyPurposeId.id_kp_timeStamping));

        // finally, sign the certificate with the private key of the same KeyPair
        X509Certificate cert = certGen.generate(keyPair.getPrivate(), "BC");
        return cert;
    }

    public void addBouncyCastleAsSecurityProvider() {
        Security.addProvider(new BouncyCastleProvider());
    }
}

For certGen.generate(keyPair.getPrivate(), "BC"); to work, BouncyCastle has to be added as a Security Provider.

I confirmed that it works with this maven dependency:

    org.bouncycastle
    bcprov-jdk16
    1.38