How to export private key from a keystore of self-signed certificate

Question

I just created a self-signed certificate on a linux box running tomcat 6.

I created the keys like this, valid for 10 years:

keytool -genkey -alias tomcatorange -keyalg RSA -validity 3650

and copied the keystore into a folder in tomcat, and updated server.xml to point at the keystore.

Now my network admin is asking for the both the public and private key ( for our load balancer)

I can generate the public key using:

openssl s_client -connect mydomain.com:8443

But how can I export/retrieve the private key?

Answer 1

It is a little tricky. First you can use keytool to put the private key into PKCS12 format, which is more portable/compatible than Java's various keystore formats. Here is an example taking a private key with alias 'mykey' in a Java keystore and copying it into a PKCS12 file named myp12file.p12. [note that on most screens this command extends beyond the right side of the box: you need to scroll right to see it all]

keytool -v -importkeystore -srckeystore .keystore -srcalias mykey -destkeystore myp12file.p12 -deststoretype PKCS12
Enter destination keystore password:  
Re-enter new password: 
Enter source keystore password:  
[Storing myp12file.p12]

Now the file myp12file.p12 contains the private key in PKCS12 format which may be used directly by many software packages or further processed using the openssl pkcs12 command. For example,

openssl pkcs12 -in myp12file.p12 -nocerts -nodes
Enter Import Password:
MAC verified OK
Bag Attributes
    friendlyName: mykey
    localKeyID: 54 69 6D 65 20 31 32 37 31 32 37 38 35 37 36 32 35 37 
Key Attributes: <No Attributes>
-----BEGIN RSA PRIVATE KEY-----
MIIC...
.
.
.
-----END RSA PRIVATE KEY-----

Prints out the private key unencrypted.

Note that this is a private key, and you are responsible for appreciating the security implications of removing it from your Java keystore and moving it around.

Answer 2

Use Keystore Explorer gui - http://keystore-explorer.sourceforge.net/ - allows you to extract the private key from a .jks in various formats.

Answer 3

http://anandsekar.github.io/exporting-the-private-key-from-a-jks-keystore/

public class ExportPrivateKey {
        private File keystoreFile;
        private String keyStoreType;
        private char[] password;
        private String alias;
        private File exportedFile;

        public static KeyPair getPrivateKey(KeyStore keystore, String alias, char[] password) {
                try {
                        Key key=keystore.getKey(alias,password);
                        if(key instanceof PrivateKey) {
                                Certificate cert=keystore.getCertificate(alias);
                                PublicKey publicKey=cert.getPublicKey();
                                return new KeyPair(publicKey,(PrivateKey)key);
                        }
                } catch (UnrecoverableKeyException e) {
        } catch (NoSuchAlgorithmException e) {
        } catch (KeyStoreException e) {
        }
        return null;
        }

        public void export() throws Exception{
                KeyStore keystore=KeyStore.getInstance(keyStoreType);
                BASE64Encoder encoder=new BASE64Encoder();
                keystore.load(new FileInputStream(keystoreFile),password);
                KeyPair keyPair=getPrivateKey(keystore,alias,password);
                PrivateKey privateKey=keyPair.getPrivate();
                String encoded=encoder.encode(privateKey.getEncoded());
                FileWriter fw=new FileWriter(exportedFile);
                fw.write(“—–BEGIN PRIVATE KEY—–\n“);
                fw.write(encoded);
                fw.write(“\n“);
                fw.write(“—–END PRIVATE KEY—–”);
                fw.close();
        }


        public static void main(String args[]) throws Exception{
                ExportPrivateKey export=new ExportPrivateKey();
                export.keystoreFile=new File(args[0]);
                export.keyStoreType=args[1];
                export.password=args[2].toCharArray();
                export.alias=args[3];
                export.exportedFile=new File(args[4]);
                export.export();
        }
}

Answer 4

public static void main(String[] args) {

try {
        String keystorePass = "20174";
        String keyPass = "rav@789";
        String alias = "TyaGi!";
        InputStream keystoreStream = new FileInputStream("D:/keyFile.jks");
        KeyStore keystore = KeyStore.getInstance("JCEKS");
        keystore.load(keystoreStream, keystorePass.toCharArray());
        Key key = keystore.getKey(alias, keyPass.toCharArray());

        byte[] bt = key.getEncoded();
        String s = new String(bt);
        System.out.println("------>"+s);      
        String str12 = Base64.encodeBase64String(bt);

        System.out.println("Fetched Key From JKS : " + str12);

    } catch (KeyStoreException | IOException | NoSuchAlgorithmException | CertificateException | UnrecoverableKeyException ex) {
        System.out.println(ex);

    }
}