Programmatically Import CA trust cert into existing keystore file without using keytool

Question

I would like to create a JAVA program that import the .cer CA into the existing keystore file. So that end-user can insert the CA cert more convenience(without using CMD and key in the command).

Is that anywhere that JAVA code can do this?

i try some way, but still fail in getting the cert into java

CertificateFactory cf = CertificateFactory.getInstance("X.509");
InputStream certstream = fullStream (certfile);
Certificate certs = cf.generateCertificates(certstream);

the error is incompatible types, is there any other suggestion?

Thanks Lot

Answer 1

The following code inserts the CA cert file yourcert.cer into your keystore without using keytool:

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.security.Key;
import java.security.KeyStore;
import java.security.cert.Certificate;
import java.io.IOException;
import java.io.InputStream;
import java.io.DataInputStream;
import java.io.ByteArrayInputStream;
import java.security.spec.*;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.util.Collection;

public class ImportCA {

    public static void main(String[] argv) throws Exception {
        String certfile = "yourcert.cer"; /*your cert path*/
        FileInputStream is = new FileInputStream("yourKeyStore.keystore");

        KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
        keystore.load(is, "yourKeyStorePass".toCharArray());

        String alias = "youralias";
        char[] password = "yourKeyStorePass".toCharArray();

        //////

        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        InputStream certstream = fullStream (certfile);
        Certificate certs =  cf.generateCertificate(certstream);

        ///
        File keystoreFile = new File("yourKeyStorePass.keystore");
        // Load the keystore contents
        FileInputStream in = new FileInputStream(keystoreFile);
        keystore.load(in, password);
        in.close();

        // Add the certificate
        keystore.setCertificateEntry(alias, certs);

        // Save the new keystore contents
        FileOutputStream out = new FileOutputStream(keystoreFile);
        keystore.store(out, password);
        out.close();
    }

    private static InputStream fullStream ( String fname ) throws IOException {
        FileInputStream fis = new FileInputStream(fname);
        DataInputStream dis = new DataInputStream(fis);
        byte[] bytes = new byte[dis.available()];
        dis.readFully(bytes);
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
        return bais;
    }
}

Answer 2

Download certs from links and store into specific path.. then load that file into trustStore during runtime using below code.. i hope this exaple will help you..

KeyStore keyStore = KeyStore.getInstance("JKS");
String fileName = "D:\\certs_path\\cacerts"; // cerrtification file path
System.setProperty("javax.net.ssl.trustStore", fileName);

Answer 3

Sorry, this answer brings nothing new but the code in the accepted answer is so terrible that I just have to post it. It's just a polished version, nothing more. So consider copy/pasting from here but upvoting the accepted answer rather than this one.

    public static void addX509CertificateToTrustStore(String certPath, String certAlias, String storePath, String storePassword, String storeType)
            throws FileNotFoundException, KeyStoreException, CertificateException, IOException, NoSuchAlgorithmException {

        char[] storePasswordCharArr = Objects.requireNonNull(storePassword, "").toCharArray();

        KeyStore keystore;
        try (FileInputStream storeInputStream = new FileInputStream(storePath);
                FileInputStream certInputStream = new FileInputStream(certPath)) {
            keystore = KeyStore.getInstance(storeType);
            keystore.load(storeInputStream, storePasswordCharArr);

            CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
            Certificate certificate = certificateFactory.generateCertificate(certInputStream);

            keystore.setCertificateEntry(certAlias, certificate);
        } finally {
        }

        try (FileOutputStream storeOutputStream = new FileOutputStream(storePath)) {
            keystore.store(storeOutputStream, storePasswordCharArr);
        } finally {
        }
    }