[java] Import PEM into Java Key Store

I am trying to connect to an SSL server which requires me to authenticate myself. In order to use SSL over Apache MINA I need a suitable JKS file. However, I have only been given a .PEM file.

How would I go about creating a JKS file from a PEM file?

I've developed http://code.google.com/p/java-keyutil/ which imports PEM certificates straight into a Java keystore. Its primary purpose is to import a multi-part PEM Operating System certificate bundles such as ca-bundle.crt. These often includes headers which keytool cannot handle

</self promotion>

If you only want to import a certificate in PEM format into a keystore, keytool will do the job:

keytool -import -alias *alias* -keystore cacerts -file *cert.pem*

I'm always forgetting how to do this because it's something that I just do once in a while, this is one possible solution, and it just works:

1. Go to your favourite browser and download the main certificate from the secured website.

2. Execute the two following lines of code:

   $ openssl x509 -outform der -in GlobalSignRootCA.crt -out GlobalSignRootCA.der
   $ keytool -import -alias GlobalSignRootCA -keystore GlobalSignRootCA.jks -file GlobalSignRootCA.der
   

3. If executing in Java SE environment add the following options:

   $ java -Djavax.net.ssl.trustStore=GlobalSignRootCA.jks -Djavax.net.ssl.trustStorePassword=trustStorePassword -jar MyJar.jar
   

4. Or add the following to the java code:

   System.setProperty("javax.net.ssl.trustStore", "GlobalSignRootCA.jks");
   System.setProperty("javax.net.ssl.trustStorePassword","trustStorePassword");
   

The other option for step 2 is to just using the keytool command. Bellow is an example with a chain of certificates:

$ keytool -import -file org.eu.crt -alias orgcrt -keystore globalsignrs.jks
$ keytool -import -file GlobalSignOrganizationValidationCA-SHA256-G2.crt -alias globalsignorgvalca -keystore globalsignrs.jks
$ keytool -import -file GlobalSignRootCA.crt -alias globalsignrootca -keystore globalsignrs.jks

There is also a GUI tool that allows visual JKS creation and certificates importing.

http://portecle.sourceforge.net/

Portecle is a user friendly GUI application for creating, managing and examining keystores, keys, certificates, certificate requests, certificate revocation lists and more.

I used Keystore Explorer

1. Open JKS with a private key
2. Examine signed PEM from CA
3. Import key
4. Save JKS

I got it from internet. It works pretty good for pem files that contains multiple entries.

#!/bin/bash
pemToJks()
{
        # number of certs in the PEM file
        pemCerts=$1
        certPass=$2
        newCert=$(basename "$pemCerts")
        newCert="${newCert%%.*}"
        newCert="${newCert}"".JKS"
        ##echo $newCert $pemCerts $certPass
        CERTS=$(grep 'END CERTIFICATE' $pemCerts| wc -l)
        echo $CERTS
        # For every cert in the PEM file, extract it and import into the JKS keystore
        # awk command: step 1, if line is in the desired cert, print the line
        #              step 2, increment counter when last line of cert is found
        for N in $(seq 0 $(($CERTS - 1))); do
          ALIAS="${pemCerts%.*}-$N"
          cat $pemCerts |
                awk "n==$N { print }; /END CERTIFICATE/ { n++ }" |
                $KEYTOOLCMD -noprompt -import -trustcacerts \
                                -alias $ALIAS -keystore $newCert -storepass $certPass
        done
}
pemToJks <pem to import> <pass for new jks>

If you need an easy way to load PEM files in Java without having to deal with external tools (opensll, keytool), here is my code I use in production :

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.security.KeyFactory;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.security.interfaces.RSAPrivateKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.ArrayList;
import java.util.List;

import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLServerSocketFactory;
import javax.xml.bind.DatatypeConverter;

public class PEMImporter {

    public static SSLServerSocketFactory createSSLFactory(File privateKeyPem, File certificatePem, String password) throws Exception {
        final SSLContext context = SSLContext.getInstance("TLS");
        final KeyStore keystore = createKeyStore(privateKeyPem, certificatePem, password);
        final KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
        kmf.init(keystore, password.toCharArray());
        final KeyManager[] km = kmf.getKeyManagers();
        context.init(km, null, null);
        return context.getServerSocketFactory();
    }

    /**
     * Create a KeyStore from standard PEM files
     * 
     * @param privateKeyPem the private key PEM file
     * @param certificatePem the certificate(s) PEM file
     * @param the password to set to protect the private key
     */
    public static KeyStore createKeyStore(File privateKeyPem, File certificatePem, final String password)
            throws Exception, KeyStoreException, IOException, NoSuchAlgorithmException, CertificateException {
        final X509Certificate[] cert = createCertificates(certificatePem);
        final KeyStore keystore = KeyStore.getInstance("JKS");
        keystore.load(null);
        // Import private key
        final PrivateKey key = createPrivateKey(privateKeyPem);
        keystore.setKeyEntry(privateKeyPem.getName(), key, password.toCharArray(), cert);
        return keystore;
    }

    private static PrivateKey createPrivateKey(File privateKeyPem) throws Exception {
        final BufferedReader r = new BufferedReader(new FileReader(privateKeyPem));
        String s = r.readLine();
        if (s == null || !s.contains("BEGIN PRIVATE KEY")) {
            r.close();
            throw new IllegalArgumentException("No PRIVATE KEY found");
        }
        final StringBuilder b = new StringBuilder();
        s = "";
        while (s != null) {
            if (s.contains("END PRIVATE KEY")) {
                break;
            }
            b.append(s);
            s = r.readLine();
        }
        r.close();
        final String hexString = b.toString();
        final byte[] bytes = DatatypeConverter.parseBase64Binary(hexString);
        return generatePrivateKeyFromDER(bytes);
    }

    private static X509Certificate[] createCertificates(File certificatePem) throws Exception {
        final List<X509Certificate> result = new ArrayList<X509Certificate>();
        final BufferedReader r = new BufferedReader(new FileReader(certificatePem));
        String s = r.readLine();
        if (s == null || !s.contains("BEGIN CERTIFICATE")) {
            r.close();
            throw new IllegalArgumentException("No CERTIFICATE found");
        }
        StringBuilder b = new StringBuilder();
        while (s != null) {
            if (s.contains("END CERTIFICATE")) {
                String hexString = b.toString();
                final byte[] bytes = DatatypeConverter.parseBase64Binary(hexString);
                X509Certificate cert = generateCertificateFromDER(bytes);
                result.add(cert);
                b = new StringBuilder();
            } else {
                if (!s.startsWith("----")) {
                    b.append(s);
                }
            }
            s = r.readLine();
        }
        r.close();

        return result.toArray(new X509Certificate[result.size()]);
    }

    private static RSAPrivateKey generatePrivateKeyFromDER(byte[] keyBytes) throws InvalidKeySpecException, NoSuchAlgorithmException {
        final PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
        final KeyFactory factory = KeyFactory.getInstance("RSA");
        return (RSAPrivateKey) factory.generatePrivate(spec);
    }

    private static X509Certificate generateCertificateFromDER(byte[] certBytes) throws CertificateException {
        final CertificateFactory factory = CertificateFactory.getInstance("X.509");
        return (X509Certificate) factory.generateCertificate(new ByteArrayInputStream(certBytes));
    }

}

Have fun.

In my case I had a pem file which contained two certificates and an encrypted private key to be used in mutual SSL authentication. So my pem file looked like this:

-----BEGIN CERTIFICATE-----

...

-----END CERTIFICATE-----

-----BEGIN RSA PRIVATE KEY-----

Proc-Type: 4,ENCRYPTED

DEK-Info: DES-EDE3-CBC,C8BF220FC76AA5F9

...

-----END RSA PRIVATE KEY-----

-----BEGIN CERTIFICATE-----

...

-----END CERTIFICATE-----

Here is what I did

Split the file into three separate files, so that each one contains just one entry, starting with ---BEGIN.. and ending with ---END.. lines. Lets assume we now have three files: cert1.pem, cert2.pem, and pkey.pem.

Convert pkey.pem into DER format using openssl and the following syntax:

openssl pkcs8 -topk8 -nocrypt -in pkey.pem -inform PEM -out pkey.der -outform DER

Note, that if the private key is encrypted you need to supply a password( obtain it from the supplier of the original pem file ) to convert to DER format, openssl will ask you for the password like this: "enter a passphrase for pkey.pem: ".

If conversion is successful, you will get a new file called pkey.der.

Create a new java keystore and import the private key and the certificates:

String keypass = "password";  // this is a new password, you need to come up with to protect your java key store file
String defaultalias = "importkey";
KeyStore ks = KeyStore.getInstance("JKS", "SUN");

// this section does not make much sense to me, 
// but I will leave it intact as this is how it was in the original example I found on internet:   
ks.load( null, keypass.toCharArray());
ks.store( new FileOutputStream ( "mykeystore"  ), keypass.toCharArray());
ks.load( new FileInputStream ( "mykeystore" ),    keypass.toCharArray());
// end of section..


// read the key file from disk and create a PrivateKey

FileInputStream fis = new FileInputStream("pkey.der");
DataInputStream dis = new DataInputStream(fis);
byte[] bytes = new byte[dis.available()];
dis.readFully(bytes);
ByteArrayInputStream bais = new ByteArrayInputStream(bytes);

byte[] key = new byte[bais.available()];
KeyFactory kf = KeyFactory.getInstance("RSA");
bais.read(key, 0, bais.available());
bais.close();

PKCS8EncodedKeySpec keysp = new PKCS8EncodedKeySpec ( key );
PrivateKey ff = kf.generatePrivate (keysp);


// read the certificates from the files and load them into the key store:

Collection  col_crt1 = CertificateFactory.getInstance("X509").generateCertificates(new FileInputStream("cert1.pem"));
Collection  col_crt2 = CertificateFactory.getInstance("X509").generateCertificates(new FileInputStream("cert2.pem"));

Certificate crt1 = (Certificate) col_crt1.iterator().next();
Certificate crt2 = (Certificate) col_crt2.iterator().next();
Certificate[] chain = new Certificate[] { crt1, crt2 };

String alias1 = ((X509Certificate) crt1).getSubjectX500Principal().getName();
String alias2 = ((X509Certificate) crt2).getSubjectX500Principal().getName();

ks.setCertificateEntry(alias1, crt1);
ks.setCertificateEntry(alias2, crt2);

// store the private key
ks.setKeyEntry(defaultalias, ff, keypass.toCharArray(), chain );

// save the key store to a file         
ks.store(new FileOutputStream ( "mykeystore" ),keypass.toCharArray());

(optional) Verify the content of your new key store:

$ keytool -list -keystore mykeystore -storepass password

Keystore type: JKS Keystore provider: SUN

Your keystore contains 3 entries:

• cn=...,ou=...,o=.., Sep 2, 2014, trustedCertEntry, Certificate fingerprint (SHA1): 2C:B8: ...

• importkey, Sep 2, 2014, PrivateKeyEntry, Certificate fingerprint (SHA1): 9C:B0: ...

• cn=...,o=...., Sep 2, 2014, trustedCertEntry, Certificate fingerprint (SHA1): 83:63: ...

(optional) Test your certificates and private key from your new key store against your SSL server: ( You may want to enable debugging as an VM option: -Djavax.net.debug=all )

        char[] passw = "password".toCharArray();
        KeyStore ks = KeyStore.getInstance("JKS", "SUN");
        ks.load(new FileInputStream ( "mykeystore" ), passw );

        KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
        kmf.init(ks, passw);

        TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
        tmf.init(ks);
        TrustManager[] tm = tmf.getTrustManagers();

        SSLContext sclx = SSLContext.getInstance("TLS");
        sclx.init( kmf.getKeyManagers(), tm, null);

        SSLSocketFactory factory = sclx.getSocketFactory();
        SSLSocket socket = (SSLSocket) factory.createSocket( "192.168.1.111", 443 );
        socket.startHandshake();

        //if no exceptions are thrown in the startHandshake method, then everything is fine..

Finally register your certificates with HttpsURLConnection if plan to use it:

        char[] passw = "password".toCharArray();
        KeyStore ks = KeyStore.getInstance("JKS", "SUN");
        ks.load(new FileInputStream ( "mykeystore" ), passw );

        KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
        kmf.init(ks, passw);

        TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
        tmf.init(ks);
        TrustManager[] tm = tmf.getTrustManagers();

        SSLContext sclx = SSLContext.getInstance("TLS");
        sclx.init( kmf.getKeyManagers(), tm, null);

        HostnameVerifier hv = new HostnameVerifier()
        {
            public boolean verify(String urlHostName, SSLSession session)
            {
                if (!urlHostName.equalsIgnoreCase(session.getPeerHost()))
                {
                    System.out.println("Warning: URL host '" + urlHostName + "' is different to SSLSession host '" + session.getPeerHost() + "'.");
                }
                return true;
            }
        };

        HttpsURLConnection.setDefaultSSLSocketFactory( sclx.getSocketFactory() );
        HttpsURLConnection.setDefaultHostnameVerifier(hv);

Although this question is pretty old and it has already a-lot answers, I think it is worth to provide an alternative. Using native java classes makes it very verbose to just use pem files and almost forces you wanting to convert the pem files into p12 or jks files as using p12 or jks files are much easier. I want to give anyone who wants an alternative for the already provided answers.

GitHub - SSLContext Kickstart

var keyManager = PemUtils.loadIdentityMaterial("certificate-chain.pem", "private-key.pem");
var trustManager = PemUtils.loadTrustMaterial("some-trusted-certificate.pem");

var sslFactory = SSLFactory.builder()
          .withIdentityMaterial(keyManager)
          .withTrustMaterial(trustManager)
          .build();

var sslContext = sslFactory.getSslContext();

I need to provide some disclaimer here, I am the library maintainer