How to configure SSL
This is an overview of how to configure SSL for Jetty, which uses Sun's reference implementation for the Java Secure Sockets Extension (JSSE).
Configuring SSL can be a confusing experience of keys, certificates, protocols and formats, thus it helps to have a reasonable understanding
of the basics. The following links provide some good starting points:
- Other tools:
- Open SSL:
The following steps are required to configure Jetty for SSL:
Step 1: Generate or obtain a public/private key pair and x509 certificate.
Step 2: Optionally obtain a certificate from a known certificate authority.
Step 3: Load the keys and the certificates into a JSSE Keystore.
Step 4: Configure a JsseListener with the location and passwords for the keystore.
OpenSSL Versus Keytool
For testing, keytool is probably the simplest way to generate the key and certificate you will need. However, IBMs keyman is also pretty good and provides a GUI rather than a command line.
The OpenSSL tools can also be used to generate keys and certificates or to convert ones that have been used with Apache or other servers.
The OpenSSL tool suite is commonly used by other servers such as Apache to generate manipulate keys and certificates. So you may already have some keys and certificates created by openssl, or openssl may be more trusted than keytool or some certificate authorities for step 2 may also prefer the formats produced by ssl.
If you want the option of using the same certificate with Jetty or a web server such as Apache not written in Java, you may prefer to
generate your private key and certificate with openSSL. The Java keytool does not provide options for exporting private keys, and Apache
needs the private key. If you create the key and certificate with openSSL your non-Java web server will have ready access to it.
Step 1: Keys and Certificates
The simplest way generate keys and certificates is to use the keytool application that comes with the JDK, as it generates keys and certificates directly into the keystore. See Step 1a.
If you already have keys and certificates, please goto Step 3 to load them into a JSSE key store.
If you have a renewal certificate to replace one that is expiring, take a look at Renewing Certificates.
The commands below only generate minimal keys and certificates. You should read the full manuals of the tools you are using if you wish to specify:
- Key size.
- Certificate expiry.
- Alternate security providers.
Step 1a: Generating a certificate with JDK keytool
The following command will generate a key pair and certificate directly into a keystore:
This command will prompt for information about the certificate and for passwords to protect both the keystore and the keys within it. The only mandatory response is to provide the fully qualified host name of the server at the "first and last name" prompt. For example:
You now have the minimal requirements to run an SSL connection and could proceed directly to Step 4 to configure an SSL listener.
However the certificate you have generated will not be trusted by the browser and the user will be prompted to this effect. This is often sufficient for testing, but most public site will need to Step 2a to obtain a certificate trusted by most popular clients.
Step 1b: Keys and Certificates with openssl
The following command generates a key pair in the file jetty.key:
You may also wish to use the -rand file argument to provide an arbitrary file to help seed the random number generator.
The following command generates a certificate for the key into the file jetty.crt:
This command will prompt for information about the certificate and for passwords to protect both the keystore and the keys within it. The only mandatory response is to provide the fully qualified host name of the server at the "Common Name" prompt. For example:
You now have the minimal requirements to run an SSL connection and could proceed directly to Step 3 to load these keys and certificates into a JSSE keystore. However the certificate you have generated will not be trusted by the browser and the user will be prompted to this effect. This is often sufficient for testing, but most public site will need to Step 2b to obtain a certificate trusted by most popular clients.
Step 1c: Keys and Certificates from other sources
If you have keys and certificates from other sources, then you can proceed directly to Step 3.
Step 2: Request a trusted certificate
The keys and certificats generated in steps 1a and 1b are sufficient to run an SSL listener. However the certificate you have generated will not be trusted by the browser and the user will be prompted to this effect.
To obtain a certificate that will be trusted by most common browsers, you need to request a well known certificate authority (CA) to sign your key/certificate. Such trusted CAs include: AddTrust, Entrust, GeoTrust, RSA Data Security, Thawte, VISA, ValiCert, Verisign, beTRUSTed, among others.
Each CA will have their own instructions which should be followed (look for JSSE or openssl sections), but all will involved a step to
generate a certificate signing request (CSR).
Step 2a: CSR from keytool
The following commands generates the file jetty.csr using keytool for a key/cert already in the keystore:
Step 2b: CSR from openssl
The following commands generates the file jetty.csr using openssl for a key in the file jetty.key:
Note that this command only uses the existing key from jetty.key file and not a certificate in jetty.crt generated by step 1b. The details for the certificate need to be entered again.
Step 3: Loading Keys and Certificates
Once a CA has sent you a certificate, or if you generated your own certificate without keytool, then it will need to be loaded into
a JSSE keystore. If you did not use keytool to generate the key, then it will also need to be loaded into the keystore.
Step 3a: Loading Certificates with keytool
A certificate in PEM form may be directly loaded into a keystore with keytool. The PEM format is a text encoding of certificates and is produced by openssl (as in step 1b) and is returned by some CAs. An example PEM file is:
The following command will load a PEM encoded certificate in the jetty.crt file into a JSSE keystore:
Depending on the situation you may not require the
-trustcacerts option. Try the operation without it if you like.
NOTE That you need both the private key and the certificate in the keystore. So the certificate should be loaded into the keystore used to generate the CSR (step 2a). If your key pair is not in a keystore (eg if generated as step 1b), then you will need to use the PKCS12 format to load both key and certificate as in step 3b.
If the certificate your receive from the CA is not in a format that keytool understands, then the openssl command can be used to convert
Step 3b) Loading keys and certificates via PKCS12
If you have a key and certificate in separate files, they need to be combined into a PKCS12 format file to be loaded into a new keystore. The certificate can be one you generated yourself or one that has been returned from a CA in response to your CSR.
The following openssl command will combine the keys in jetty.key and the certificate in the jetty.crt file into the jetty.pkcs12 file:
If you have a chain of certificates, because your CA is an intermediary, build the pkcs12 file like this:
The order of certificates must be from server to rootCA, as per RFC2246 section 7.4.2.
OpenSSL is going to ask you for an "export password". A non-empty password seems to be required to make the next step work. The
resulting PKCS12 file may be loaded into a JSSE keystore with the following jetty utility class:
This asks for two passphrases. Give the password from the last step as the input passphrase and you are set. The "output passphrase" will need to appear in your jetty.xml config file as both the Password and KeyPassword of the SunJsseListener that will use the certificate.