Add Java KeyStore and client authentication

* Add instructions on how a Java KeyStore can be generated from the keys
  and certificates provided in this example. This is useful for
  situations where you have a Node.js client talking to a Java server.
* Added intructions on how client authentication could be added to the
  client side.

.gitignore

@@ -25,3 +25,7 @@ build/Release
 # Deployed apps should consider commenting this line out:
 # see https://npmjs.org/doc/faq.html#Should-I-check-my-node_modules-folder-into-git
 node_modules
+
+# IntelliJ
+.idea
+*.iml

README.md

@@ -125,6 +125,74 @@ So instead of trying to work through eleventeen brazillion errors
 about self-signed certs, you can just create an authority and then
 add the authority to your chain (viola, now it's trusted).
 
+Client Authentication
+====
+
+In the example above, the server trusts the client without the need for the client to be authenticated.
+So, a common enhancement to the example above would be to add client authentication.
+To add client authentication, it's necessary to generate a client key and have it signed by the CA defined above.
+Execute `make-client-key-certificate.sh` to generate key and certificate.
+To use generated key and certificate, `key`, `cert` and `passphrase` TLS options need to be added, e.g.:
+
+```
+var ca = fs.readFileSync(path.join(__dirname, 'certs', 'client', 'chain.pem'));
+var key = fs.readFileSync(path.join(__dirname, 'certs', 'client-auth', 'privkey.pem'));
+var passphrase = 'secret';
+var cert = fs.readFileSync(path.join(__dirname, 'certs', 'client-auth', 'cert.pem'));
+
+var options = {
+  host: hostname
+, port: port
+, path: '/'
+, ca: ca
+, key: key
+, passphrase: passphrase
+, cert: cert
+};
+```
+
+Generating Java Key Stores
+====
+
+If the server component is written in Java, the server needs to be plugged with a Java KeyStore containing security certificates.
+In the example above, the `fullchain.pem` file needs to be converted into a Java KeyStore file.
+To create a Java KeyStore file, the JDK needs to be installed and have `keytool` utility in the path.
+To do that, please follow these instructions:
+
+    $ mkdir certs/java/server
+    $ openssl pkcs12 \
+      -export \
+      -inkey certs/server/privkey.pem \
+      -in certs/server/fullchain.pem \
+      -name test \
+      -out certs/java/server/keystore_server.p12
+    $ keytool \
+      -importkeystore \
+      -srckeystore certs/java/server/keystore_server.p12 \
+      -srcstoretype pkcs12 \
+      -destkeystore certs/java/server/keystore_server.jks
+
+Trust Store for Client Authentication
+----
+
+If using client authentication, it is necessary for the server to trust to the client.
+To do that, it's necessary for a trust store to be created that contains the client's public key.
+Such a trust store can be created using these steps:
+
+    $ rsync -a certs/ca/my-root-ca.crt.pem certs/client-auth/chain.pem
+    $ cat certs/client-auth/cert.pem certs/client-auth/chain.pem > certs/client-auth/fullchain.pem
+    $ openssl pkcs12
+      \-export
+      \-inkey certs/client-auth/privkey.pem
+      \-in certs/client-auth/fullchain.pem
+      \-name test
+      \-out certs/infinispan/trustore_server.p12
+    $ keytool
+      \-importkeystore
+      \-srckeystore certs/infinispan/trustore_server.p12
+      \-srcstoretype pkcs12
+      \-destkeystore certs/infinispan/trustore_server.jks
+
 Other SSL Resources
 =========
 

make-client-key-and-certificate.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+FQDN=$1
+
+# make directories to work from
+mkdir -p certs/{client-auth}
+
+# Generate a client private key
+openssl genrsa \
+  -passout pass:secret \
+  -out certs/client-auth/privkey.pem \
+  2048
+
+
+# Create a request from your Device, which your Root CA will sign
+openssl req -new \
+  -key certs/client-auth/privkey.pem \
+  -out certs/tmp/client-csr.pem \
+  -subj "/C=US/ST=Utah/L=Provo/O=ACME Tech Inc/CN=${FQDN}"
+
+# Sign the request from Device with your Root CA
+openssl x509 \
+  -req -in certs/tmp/client-csr.pem \
+  -CA certs/ca/my-root-ca.crt.pem \
+  -CAkey certs/ca/my-root-ca.key.pem \
+  -CAcreateserial \
+  -out certs/client-auth/cert.pem \
+  -days 500
+
+# Create a public key, for funzies
+# see https://gist.github.com/coolaj86/f6f36efce2821dfb046d
+openssl rsa \
+  -in certs/server/privkey.pem \
+  -pubout -out certs/client/pubkey.pem
+
+# Put things in their proper place
+rsync -a certs/ca/my-root-ca.crt.pem certs/server/chain.pem
+rsync -a certs/ca/my-root-ca.crt.pem certs/client/chain.pem
+cat certs/server/cert.pem certs/server/chain.pem > certs/server/fullchain.pem