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 Resin Server | Application Server (Java EE Certified) and Web Server

resin 4.0 ssl support

Resin supports SSL for both HTTP transport level encryption as well as server authentication. Both Apache OpenSSL and JSSE aere supported as SSL implementations.

What SSL provides

SSL provides two kinds of protection, encryption and server authentication.


public key
A set of bytes used to encrypt data and verify signatures. The key is public because it can be made available without a loss of security. The public key can only be used for encryption; it cannot decrypt anything. A public key always has a corresponding private key.

SSL provides encryption of the data traffic betweeen a client and a server. When the traffic is encrypted, an interception of that traffic will not reveal the contents because they have been encrypted - it will be unusable nonsense.

private key
A set of bytes used to decrypt data and generate signatures. The key is private because it must be kept secret or there will be a loss of security. The private key is used for decryption of data that has been encrypted with the corresponding public key.

SSL uses public key cryptography. Public key cryptography is based upon a pair of keys, the public key and the private key. The public key is used to encrypt the data. Only the corresponding private key can successfully decrypt the data.

For example, when a browser connects to Resin, Resin provides the browser a public key. The browser uses the public key to encrypt the data, and Resin uses the private key to decrypt the data. For this reason, it is important that you never allow anyone access to the private key, if the private key is obtained by someone then they can use it to decrypt the data traffic.

Encryption is arguably the more important of the security meausures that SSL provides.

Server Authentication

A combination of a private key, identity information (such as company name), and a signature generated by a signing authority. private key.

SSL also provides the ability for a client to verify the identity of a server. This is used to protect against identity theft, where for example a malicious person imitates your server or redirects client traffic to a different server while pretending to be you.

signing authority
A company that is trusted to sign certificates. Browsers include certificates of signing authorities that they trust.

Server authentication uses the signature aspect of public key cryptography. The private key is used to sign messages, and the public key is used to verify the signature. With SSL, the validity of signatures depends upon signing authorities. Signing authorites (also called certificate authorities) are companies who have generated public keys that are included with browser software. The browser knows it can trust the signing authority, and the signing authority signs your SSL certificate, putting its stamp of approval on the information in your certificate.

certificate authority
Another name for signing authority. A company that is trusted to sign certificates. Browsers include certificates of signing authorities that they trust.

For example, after you generate your public and private key, you then generate a signing request and send it to a signing authority. This signing request contains information about your identity, this identity information is confirmed by the signing authority and ultimately displayed to the user of the browser. The signing authority validates the identity information you have provided and uses their private key to sign, and then returns a certificate to you. This certificate contains the identity information and your public key, verified by the signing authority, and is provided to the browser. Since the browser has the public key of the signing authority, it can recognize the signature and know that the identity information has been provided by someone that can be trusted.


OpenSSL is the same SSL implementation that Apache's mod_ssl uses. Since OpenSSL uses the same certificate as Apache, you can get signed certificates using the same method as for Apache's mod_ssl or following the OpenSSL instructions.

Linking to the OpenSSL Libraries on Unix

On Unix systems, Resin's libexec/ JNI library supports SSL using the OpenSSL libraries. Although the ./configure script will detect many configurations, you can specify the openssl location directly:

resin> ./configure --with-openssl=/usr/local/ssl

Obtaining the OpenSSL Libraries on Windows

On Windows systems, the resinssl.dll includes JNI code to use OpenSSL libraries (it was in resin.dll in versions before 3.0). All you need to do is to obtain an OpenSSL binary distribution and install it.

Resin on Windows 32 is compiled against the Win32 binary, you can obtain an installation package (Shining Light Productions).

Resin on Windows 64 is compiled against a Win64 binary, you can obtain an installation package Dean Lee: /dev/blog.

Once you have run the installation package, you can copy the necessary dll libraries into $RESIN_HOME:

Copying the Windows SSL libraries into $RESIN_HOME
C:\> cd %RESIN_HOME%
C:\resin-4.0.x> copy "C:\Program Files\GnuWin32\bin\libssl32.dll" .\libssl32.dll
C:\resin-4.0.x> copy "C:\Program Files\GnuWin32\bin\libeay32.dll" .\libeay32.dll

Preparing to use OpenSSL for making keys

You can make a keys/ subdirectory of $RESIN_HOME to do your work from and as a place to store your generated keys.

unix> cd $RESIN_HOME
unix> mkdir keys
unix> cd keys

win> cd %RESIN_HOME%
win> mkdir keys
win> cd keys

Using OpenSSL requires a configuration file. Unix users might find the default configuration file in /usr/ssl/openssl.cnf or /usr/share/ssl/openssl.cnf. Windows users may not have received one with their package.

Either way, it can be valuable to make your own openssl.cnf that is used just for generating the keys to use with Resin. You can use the following as a template for a file $RESIN_HOME/keys/openssl.cnf. You may want to fill in the _default values so you don't have to type them in every time.

[ req ]
 default_bits            = 1024
 distinguished_name      = req_distinguished_name

[ req_distinguished_name ]
 C                      = 2 letter Country Code, for example US
 C_default              =
 ST                     = State or Province
 ST_default             =
 L                      = City
 L_default              =
 O                      = Organization Name
 O_default              =
 OU                     = Organizational Unit Name, for example 'Marketing'
 OU_default             =
 CN                     = your domain name, for example
 CN_default             =
 emailAddress           = an email address
 emailAddress_default   =

Creating a private key

Create a private key for the server. You will be asked for a password - don't forget it! You will need this password anytime you want to do anything with this private key. But don't pick something you need to keep secret, you will need to put this password in the Resin configuration file.

creating the private key gryffindor.key
unix> openssl genrsa -des3 -out gryffindor.key 1024
win>  "C:\Program Files\GnuWin32\bin\openssl.exe" \
         genrsa -des3 -out gryffindor.key 1024

Creating a certificate

OpenSSL works by having a signed public key that corresponds to your private key. This signed public key is called a certificate. A certificate is what is sent to the browser.

You can create a self-signed certificate, or get a certificate that is signed by a certificate signer (CA).

Creating a self-signed certificate

You can create a certificate that is self-signed, which is good for testing or for saving you money. Since it is self-signed, browsers will not recognize the signature and will pop up a warning to browser users. Other than this warning, self-signed certificates work well. The browser cannot confirm that the server is who it says it is, but the data between the browser and the client is still encrypted.

creating a self-signed certificate gryffindor.crt
unix> openssl req -config ./openssl.cnf -new -key gryffindor.key \
        -x509 -out gryffindor.crt
win> "C:\Program Files\GnuWin32\bin\openssl.exe" req -config ./openssl.cnf \
         -new -key gryffindor.key -x509 -out gryffindor.crt

You will be asked to provide some information about the identity of your server, such as the name of your Organization etc. Common Name (CN) is your domain name, like: "".

Creating a certificate request

To get a certificate that is signed by a CA, first you generate a certificate signing request (CSR).

creating a certificate request gryffindor.csr
unix> openssl req -new -config ./openssl.cnf -key gryffindor.key \
      -out gryffindor.csr
win> "C:\Program Files\GnuWin32\bin\openssl.exe" req -new \
      -config ./openssl.cnf  -key gryffindor.key -out gryffindor.csr

You will be asked to provide some information about the identity of your server, such as the name of your Organization etc. Common Name (CN) is your domain name, like: "".

Send the CSR to a certificate signer (CA). You'll use the CA's instructions for Apache because the certificates are identical. Some commercial signers include:

You'll receive a gryffindor.crt file.

Most browsers are configured to recognize the signature of signing authorities. Since they recognize the signature, they will not pop up a warning message the way they will with self-signed certificates. The browser can confirm that the server is who it says it is, and the data between the browser and the client is encrypted.

resin.xml - Configuring Resin to use your private key and certificate

The OpenSSL configuration has two tags certificate-file and certificate-key-file. These correspond exactly to mod_ssl's SSLCertificateFile and SSLCertificateKeyFile. So you can use the same certificates (and documentation) from mod_ssl for Resin.

The full set of parameters is in the port configuration.

<resin xmlns="">
  <cluster id="http-tier">

  <server id="a" address="">
    <http port="443">


The default resin configuration allows you to setup open-ssl in

Setting up open ssl in
# OpenSSL certificate configuration
openssl_file : key/gryffindor.crt
openssl_key : keys/gryffindor.key
openssl_password : my-password

Testing SSL with the browser

A quick test is the following JSP.

Secure? <%= request.isSecure() %>

Testing with openssl to test the server

The openssl tool can be used as a client, showing some interesting information about the conversation between the client and the server:

unix$ openssl s_client -connect -prexit

Certificate Chains

A certificate chain is used when the signing authority is not an authority trusted by the browser. In this case, the signing authority uses a certificate which is in turn signed by a trusted authority, giving a chain of [your certificate] <-- signed by -- [untrusted signer] <-- signed by -- [trusted signer].

The Resin config parameter certificate-chain-file is used to specify a certificate chain. It is used to reference a file that is a concatenation of:

  1. your certificate file
  2. the intermediate (untrusted) certificate
  3. the root (trusted) certificate.

The certificates must be in that order, and must be in PEM format.

Example certificate chain for Instant SSL

Comodo ( is a signing authority that is untrusted by most browsers. Comodo has their certificate signed by GTECyberTrust.

Comodo gives you three certificates:

  1. your_domain.crt (signed by Comodo)
  2. ComodoSecurityServicesCA.crt (signed by GTE CyberTrust)
  3. GTECyberTrustRoot.crt (universally known root)

In addition to this, you have your key, your_domain.key. The contents of the file referred to by certificate-chain-file is a concatenation of the three certificates, in the correct order.

Creating a certificate chain file
$ cat your_domain.crt ComodoSecurityServicesCA.crt GTECyberTrustRoot.crt > chain.txt
resin.xml using a certificate chain file
<http port="443">


We recommend avoiding JSSE if possible. It is slower than using Resin's OpenSSL support and does not appear to be as stable as Apache or IIS (or Netscape/Zeus) for SSL support. In addition, JSSE is far more complicated to configure. While we've never received any problems with Resin using OpenSSL, or SSL from Apache or IIS, JSSE issues are fairly frequent.

Install JSSE from Sun

This section gives a quick guide to installing a test SSL configuration using Sun's JSSE. It avoids as many complications as possible and uses Sun's keytool to create a server certificate.

Resin's SSL support is provided by Sun's JSSE. Because of export restrictions, patents, etc, you'll need to download the JSSE distribution from Sun or get a commercial JSSE implementation.

More complete JSSE installation instructions for JSSE are at

  1. First download Sun's JSSE.
  2. Uncompress and extract the downloaded file.
  3. Install the JSSE jar files: jsse.jar, jnet.jar, and jcert.jar. You can either put them into the CLASSPATH or you can put them into $JAVA_HOME/jre/lib/ext. Since you will use "keytool" with the new jars, you need to make them visible to keytool. Just adding them to resin/lib is not enough.
  4. Register the JSSE provider ( Modify $JAVA_HOME/jre/lib/security/ so it contains something like:
    Adding the JSSE provider allows "keytool" to create a key using the RSA algorithm.

Create a test server certificate

The server certificate is the core of SSL. It will identify your server and contain the secret key to make encryption work.

  • Sun's keytool
  • A self-signed certificate using open_ssl
  • A test certificate from Thawte
  • A production certificate from one of the certificate authorities (Verisign, Thawte, etc)

In this case, we're using Sun's keytool to generate the server certificate. Here's how:

resin1.2.b2> mkdir keys
resin1.2.b2> keytool -genkey -keyalg RSA -keystore keys/server.keystore
Enter keystore password:  changeit
What is your first and last name?
What is the name of your organizational unit?
  [Unknown]:  Resin Engineering
What is the name of your organization?
  [Unknown]:  Caucho Technology, Inc.
What is the name of your City or Locality?
  [Unknown]:  San Francisco
What is the name of your State or Province?
  [Unknown]:  California
What is the two-letter country code for this unit?
  [Unknown]:  US
Is <, OU=Resin Engineering,
  O="Caucho Technology, Inc.", L=San Francisco, ST=California, C=US> correct?
  [no]:  yes

Enter key password for <mykey>
        (RETURN if same as keystore password):  changeit

Currently, the key password and the keystore password must be the same.


The Resin SSL configuration extends the http configuration with a few new elements.

<resin xmlns="">
  <cluster id="">

    <http port="8443">



Testing JSSE

With the above configuration, you can test SSL with https://localhost:8443. A quick test is the following JSP.

Secure? <%= request.isSecure() %>

Copyright © 1998-2012 Caucho Technology, Inc. All rights reserved. Resin ® is a registered trademark. Quercustm, and Hessiantm are trademarks of Caucho Technology.