# Register pre-existing keys with AWS CloudHSM key store
Register pre-existing keys with key store

For maximum security and flexibility in attributes and labeling, we recommend you generate your AWS CloudHSM signing keys using [key\$1mgmt\$1util](generate-keys.md). You can also use a Java application to generate the key in AWS CloudHSM.

The following section provides a code sample that demonstrates how to generate a new key pair on the HSM and register it using existing keys imported to the AWS CloudHSM key store. The imported keys are available for use with third-party tools such as keytool and Jarsigner. 

To use a pre-existing key, modify the code sample to look up a key by label instead of generating a new key. Sample code for looking up a key by label is available in the [KeyUtilitiesRunner.java sample](https://github.com/aws-samples/aws-cloudhsm-jce-examples/blob/master/src/main/java/com/amazonaws/cloudhsm/examples/KeyUtilitiesRunner.java) on GitHub. 

**Important**  
Registering a key stored on AWS CloudHSM with a local key store does not export the key. When the key is registered, the key store registers the key's alias (or label) and correlates locally store certificate objects with a key pair on the AWS CloudHSM. As long as the key pair is created as non-exportable, the key bits won't leave the HSM. 

```
                      	
                      	
                      	//
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package com.amazonaws.cloudhsm.examples;

import com.cavium.key.CaviumKey;
import com.cavium.key.parameter.CaviumAESKeyGenParameterSpec;
import com.cavium.key.parameter.CaviumRSAKeyGenParameterSpec;
import com.cavium.asn1.Encoder;
import com.cavium.cfm2.Util;

import javax.crypto.KeyGenerator;

import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileNotFoundException;

import java.math.BigInteger;

import java.security.*;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.KeyStore.PasswordProtection;
import java.security.KeyStore.PrivateKeyEntry;
import java.security.KeyStore.Entry;

import java.util.Calendar;
import java.util.Date;
import java.util.Enumeration;

//
// KeyStoreExampleRunner demonstrates how to load a keystore, and associate a certificate with a
// key in that keystore.
//
// This example relies on implicit credentials, so you must setup your environment correctly.
//
// https://docs.aws.amazon.com/cloudhsm/latest/userguide/java-library-install.html#java-library-credentials
//

public class KeyStoreExampleRunner {

     private static byte[] COMMON_NAME_OID = new byte[] { (byte) 0x55, (byte) 0x04, (byte) 0x03 };
     private static byte[] COUNTRY_NAME_OID = new byte[] { (byte) 0x55, (byte) 0x04, (byte) 0x06 };
     private static byte[] LOCALITY_NAME_OID = new byte[] { (byte) 0x55, (byte) 0x04, (byte) 0x07 };
     private static byte[] STATE_OR_PROVINCE_NAME_OID = new byte[] { (byte) 0x55, (byte) 0x04, (byte) 0x08 };
     private static byte[] ORGANIZATION_NAME_OID = new byte[] { (byte) 0x55, (byte) 0x04, (byte) 0x0A };
     private static byte[] ORGANIZATION_UNIT_OID = new byte[] { (byte) 0x55, (byte) 0x04, (byte) 0x0B };

     private static String helpString = "KeyStoreExampleRunner%n" +
            "This sample demonstrates how to load and store keys using a keystore.%n%n" +
            "Options%n" +
            "\t--help\t\t\tDisplay this message.%n" +
            "\t--store <filename>\t\tPath of the keystore.%n" +
            "\t--password <password>\t\tPassword for the keystore (not your CU password).%n" +
            "\t--label <label>\t\t\tLabel to store the key and certificate under.%n" +
            "\t--list\t\t\tList all the keys in the keystore.%n%n";

    public static void main(String[] args) throws Exception {
        Security.addProvider(new com.cavium.provider.CaviumProvider());
        KeyStore keyStore = KeyStore.getInstance("CloudHSM");

        String keystoreFile = null;
        String password = null;
        String label = null;
        boolean list = false;
        for (int i = 0; i < args.length; i++) {
            String arg = args[i];
            switch (args[i]) {
                case "--store":
                    keystoreFile = args[++i];
                    break;
                case "--password":
                    password = args[++i];
                    break;
                case "--label":
                    label = args[++i];
                    break;
                case "--list":
                    list = true;
                    break;
                case "--help":
                    help();
                    return;
            }
        }

        if (null == keystoreFile || null == password) {
            help();
            return;
        }

        if (list) {
            listKeys(keystoreFile, password);
            return;
        }

        if (null == label) {
            label = "Keystore Example Keypair";
        }

        //
        // This call to keyStore.load() will open the pkcs12 keystore with the supplied
        // password and connect to the HSM. The CU credentials must be specified using
        // standard CloudHSM login methods.
        //
        try {
            FileInputStream instream = new FileInputStream(keystoreFile);
            keyStore.load(instream, password.toCharArray());
        } catch (FileNotFoundException ex) {
            System.err.println("Keystore not found, loading an empty store");
            keyStore.load(null, null);
        }

        PasswordProtection passwd = new PasswordProtection(password.toCharArray());
        System.out.println("Searching for example key and certificate...");

        PrivateKeyEntry keyEntry = (PrivateKeyEntry) keyStore.getEntry(label, passwd);
        if (null == keyEntry) {
            //
            // No entry was found, so we need to create a key pair and associate a certificate.
            // The private key will get the label passed on the command line. The keystore alias
            // needs to be the same as the private key label. The public key will have ":public"
            // appended to it. The alias used in the keystore will We associate the certificate
            // with the private key.
            //
            System.out.println("No entry found, creating...");
            KeyPair kp = generateRSAKeyPair(2048, label + ":public", label);
            System.out.printf("Created a key pair with the handles %d/%d%n", ((CaviumKey) kp.getPrivate()).getHandle(), ((CaviumKey) kp.getPublic()).getHandle());

            //
            // Generate a certificate and associate the chain with the private key.
            //
            Certificate self_signed_cert = generateCert(kp);
            Certificate[] chain = new Certificate[1];
            chain[0] = self_signed_cert;
            PrivateKeyEntry entry = new PrivateKeyEntry(kp.getPrivate(), chain);

            //
            // Set the entry using the label as the alias and save the store.
            // The alias must match the private key label.
            //
            keyStore.setEntry(label, entry, passwd);

            FileOutputStream outstream = new FileOutputStream(keystoreFile);
            keyStore.store(outstream, password.toCharArray());
            outstream.close();

            keyEntry = (PrivateKeyEntry) keyStore.getEntry(label, passwd);
        }

        long handle = ((CaviumKey) keyEntry.getPrivateKey()).getHandle();
        String name = keyEntry.getCertificate().toString();
        System.out.printf("Found private key %d with certificate %s%n", handle, name);
    }

    private static void help() {
        System.out.println(helpString);
    }

    //
    // Generate a non-extractable / non-persistent RSA keypair.
    // This method allows us to specify the public and private labels, which
    // will make KeyStore aliases easier to understand.
    //
    public static KeyPair generateRSAKeyPair(int keySizeInBits, String publicLabel, String privateLabel)
            throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, NoSuchProviderException {

        boolean isExtractable = false;
        boolean isPersistent = false;
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("rsa", "Cavium");
        CaviumRSAKeyGenParameterSpec spec = new CaviumRSAKeyGenParameterSpec(keySizeInBits, new BigInteger("65537"), publicLabel, privateLabel, isExtractable, isPersistent);

        keyPairGen.initialize(spec);

        return keyPairGen.generateKeyPair();
    }

    //
    // Generate a certificate signed by a given keypair.
    //
    private static Certificate generateCert(KeyPair kp) throws CertificateException {
        CertificateFactory cf = CertificateFactory.getInstance("X509");
        PublicKey publicKey = kp.getPublic();
        PrivateKey privateKey = kp.getPrivate();
        byte[] version = Encoder.encodeConstructed((byte) 0, Encoder.encodePositiveBigInteger(new BigInteger("2"))); // version 1
        byte[] serialNo = Encoder.encodePositiveBigInteger(new BigInteger(1, Util.computeKCV(publicKey.getEncoded())));

        // Use the SHA512 OID and algorithm.
        byte[] signatureOid = new byte[] {
            (byte) 0x2A, (byte) 0x86, (byte) 0x48, (byte) 0x86, (byte) 0xF7, (byte) 0x0D, (byte) 0x01, (byte) 0x01, (byte) 0x0D };
        String sigAlgoName = "SHA512WithRSA";

         byte[] signatureId = Encoder.encodeSequence(
                                         Encoder.encodeOid(signatureOid),
                                         Encoder.encodeNull());

         byte[] issuer = Encoder.encodeSequence(
                                     encodeName(COUNTRY_NAME_OID, "<Country>"),
                                     encodeName(STATE_OR_PROVINCE_NAME_OID, "<State>"),
                                     encodeName(LOCALITY_NAME_OID, "<City>"),
                                     encodeName(ORGANIZATION_NAME_OID, "<Organization>"),
                                     encodeName(ORGANIZATION_UNIT_OID, "<Unit>"),
                                     encodeName(COMMON_NAME_OID, "<CN>")
                                 );

         Calendar c = Calendar.getInstance();
         c.add(Calendar.DAY_OF_YEAR, -1);
         Date notBefore = c.getTime();
         c.add(Calendar.YEAR, 1);
         Date notAfter = c.getTime();
         byte[] validity = Encoder.encodeSequence(
                                         Encoder.encodeUTCTime(notBefore),
                                         Encoder.encodeUTCTime(notAfter)
                                     );
         byte[] key = publicKey.getEncoded();

         byte[] certificate = Encoder.encodeSequence(
                                         version,
                                         serialNo,
                                         signatureId,
                                         issuer,
                                         validity,
                                         issuer,
                                         key);
         Signature sig;
         byte[] signature = null;
         try {
             sig = Signature.getInstance(sigAlgoName, "Cavium");
             sig.initSign(privateKey);
             sig.update(certificate);
             signature = Encoder.encodeBitstring(sig.sign());

         } catch (Exception e) {
             System.err.println(e.getMessage());
             return null;
         }

         byte [] x509 = Encoder.encodeSequence(
                         certificate,
                         signatureId,
                         signature
                         );
         return cf.generateCertificate(new ByteArrayInputStream(x509));
    }

     //
     // Simple OID encoder.
     // Encode a value with OID in ASN.1 format
     //
     private static byte[] encodeName(byte[] nameOid, String value) {
         byte[] name = null;
         name = Encoder.encodeSet(
                     Encoder.encodeSequence(
                             Encoder.encodeOid(nameOid),
                             Encoder.encodePrintableString(value)
                     )
                 );
         return name;
     }

    //
    // List all the keys in the keystore.
    //
    private static void listKeys(String keystoreFile, String password) throws Exception {
        KeyStore keyStore = KeyStore.getInstance("CloudHSM");

        try {
            FileInputStream instream = new FileInputStream(keystoreFile);
            keyStore.load(instream, password.toCharArray());
        } catch (FileNotFoundException ex) {
            System.err.println("Keystore not found, loading an empty store");
            keyStore.load(null, null);
        }

        for(Enumeration<String> entry = keyStore.aliases(); entry.hasMoreElements();) {
            System.out.println(entry.nextElement());
        }
    }

}
```