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Configuring X509 Certificate Authenticator

This page provides instructions on how to configure the X509 certificate authenticator and the WSO2 Identity Server using a sample app to demonstrate authentication.

Working with certificates

X509 authentication requires the client to possess a Public Key Certificate (PKC).

What is a Public Key Certificate (PKC) and Certificate Authority (CA)?

Public key cryptography relies on a public and private key pair to encrypt and decrypt the content. The keys are mathematically related, and content encrypted by using one of the keys can only be decrypted by using the other. The private key is kept secret. The public key is typically embedded in a binary certificate, and the certificate is published to a database that can be reached by all authorized users. The certificate binds the public key to an entity and is used to protect the information, encrypt transactions, and ensure secure communication.

Certificate Authorities, or Certificate Authorities / CAs, issue Digital Certificates. Digital Certificates are verifiable small data files that contain identity credentials to help websites, people, and devices represent their authentic online identity (authentic because the CA has verified the identity)

If X509 authentication is specified, the WSO2 IS will authenticate the client using the client’s public key certificate. To issue the digital certificate, a Certificate Authority (CA) is required. A CA issues digital certificates that contain identity credentials to help websites, people and devices represent their authentic, CA-verified, online identity.

To create a sample certificate and create your own Certificate Authority to sign the certificates, follow the following steps:

  1. The first step is to create the private RSA key:

    openssl genrsa -out rootCA.key 2048

    Here, the specified key size is 2048 bit. You can specify the key size for your private key.

  2. Based on this key you can now generate an actual certificate which is valid for 10 years using the following command:

    openssl req -new -x509 -days 3650 -key rootCA.key -out rootCA.crt
  3. You are prompted to provide the following details, and the details you provide are incorporated into the certificate request. An example is shown below. Make sure you use the values that fit your use case.

    • Country Name (2 letter code) [AU]: SL
    • State or Province Name (full name) [Some-State]: Western
    • Locality Name (eg, city) [ ]: Colombo
    • Organization Name (eg, company) [Internet Widgits Pty Ltd]: WSO2
    • Organizational Unit Name (eg, section) [ ]: QA
    • Common Name (e.g. serverFQDN or YOUR name) [ ]:
    • Email Address [ ]: [email protected]
  4. An OpenSSL CA requires new files and supporting directories. Therefore, create a new directory. Create the directory structure according to your openssl.conf format.

    mkdir -p demoCA/newcerts
  5. You also need some initial files inside your CA directory structure.

    touch demoCA/index.txt
    echo '01' > demoCA/serial
  6. For the JVM to trust your newly created certificate import your certificate into your JVM trust store by executing the following command:

    keytool -import -noprompt -trustcacerts -alias rootCA -file rootCA.crt -keystore ${JAVA_HOME}/jre/lib/security/cacerts -storepass changeit

    Got the 'permission denied' error?

    Note that when adding the certificate to the JVM trust store you may get the permission denied error. Running this command as an administrator resolves this permission issue.

    For example, if you are a Mac user, you can use sudo in front of this command to fix the permission issue.

  7. Now you have created the CA to sign the certificate. To create the server certificate follow the steps given below:

    1. Create the keystore that includes the private key by executing the following command:

      keytool -genkey -v -alias localcrt -keyalg RSA -validity 3650 -keystore localcrt.jks -storepass localpwd -keypass localpwd


      You are prompted for details after executing the above command. For "What is your first and last name?" you need to give a name without space(e.g., wso2).

      This command will create a keystore with the following details: - Keystore name: localcrt.jks - Alias of public certificate: localcrt - Keystore password: localpwd - Private key password: localpwd (this is required to be the same as keystore password)

    2. Execute the following command to generate the certificate signing request(CSR) using the generated keystore file.

      keytool -certreq -alias localcrt -file localcrt.csr -keystore localcrt.jks -storepass localpwd
    3. To enable CRL or OCSP based certificate revocation validation, configure the necessary openSSL extension configurations.

      1. Open either of the following files.

        • validation.cnf
        • /usr/lib/ssl/openssl.cnf
      2. Set the following properties under x509\_extensions.

        crlDistributionPoints = URI:
        authorityInfoAccess = OCSP;URI:
    4. Once it is done, sign the CSR, which requires the CA root key.

      openssl ca -batch -startdate 150813080000Z -enddate 250813090000Z -keyfile rootCA.key -cert rootCA.crt -policy policy_anything -out localcrt.crt -infiles localcrt.csr

      This creates a signed certificate called localcrt.crt that is valid for a specified period that is denoted by the startdate and enddate.

    5. The next step is to import the CA and signed certificate into the keystore.

      keytool -importcert -alias rootCA -file rootCA.crt -keystore localcrt.jks -storepass localpwd -noprompt
      keytool -importcert -alias localcrt -file demoCA/newcerts/01.pem -keystore localcrt.jks -storepass localpwd -noprompt
    6. Now, get the pkcs12 out of .crt file using the command given below as it is been used to import certificates to the browser.

      keytool -importkeystore -srckeystore localcrt.jks -destkeystore localhost.p12 -srcstoretype JKS -deststoretype PKCS12 -srcstorepass localpwd -deststorepass browserpwd -srcalias localcrt -destalias browserKey -srckeypass localpwd -destkeypass browserpwd -noprompt

      Make sure to use the same password you used when creating the keystore for the srcstorepass in the above step. Now you have the localhost.p12 file that you can import into your browser as explained in the import certificate section.

  8. Next, create a new trust store and import the server certificate into the trust store using the following commands:

    keytool -import -keystore cacerts.jks -storepass cacertspassword -alias rootCA -file rootCA.crt -noprompt
    keytool -importcert -alias localcrt -file localcrt.crt -keystore cacerts.jks -storepass cacertspassword -noprompt


    The User objects in the LDAP directory hierarchy have designators that start with CN, meaning Common Name. The CN designator applies to all but a few object types. Active Directory only uses two other object designators (although LDAP defines several).

Once you have done the above steps, you have the keystore (localcrt.jks), truststore (cacerts.jks), and pkcs12 (localhost.p12) files that you need to use later on in this guide.

Configuring the X509 certificate for the app

  1. Download the WSO2 Identity Server.

  2. Replace your keystore file path, keystore password, trust store file path and trust store password (you can use the keystore and truststore, which you created in the Working with Certificates section) in the following configuration and add it to the <IS_HOME>/repository/conf/deployment.toml file.

    ssl_protocol = "TLS"


    1. To function properly, this connector should come first in the order. Otherwise, when mutual SSL takes place, the already existing connector (9443) will be picked up and the certificate will not be retrieved correctly.

    2. The clientAuth attribute causes the Tomcat to require the client with providing a certificate that can be configured as follows.

    -   `true` : valid client certificate required for a connection to succeed
    -   `want` : use a certificate if available, but still connect if no certificate is available
    -   `false` : no client certificate is required or validated
    • The truststoreFile attributes specifies the location of the truststore that contains the trusted certificate issuers.

Disabling certificate validation

The location that is used to disable certificate validation depends on whether WSO2 Identity Server was started at least once or not.

  • If you have never started WSO2 Identity Server before, the configurations should be made on the certificate-validation.xml file.

  • If you have started WSO2 Identity Server at least once, the configurations should be made on the registry parameters.

Disabling certificate validation in an unstarted WSO2 IS Pack

Follow the steps below to disable certificate validation if your WSO2 Identity Server pack has never been started.

  1. Open the certificate-validation.xml file in the <IS_HOME>/repository/conf/security repository.

  2. Disable certificate validation.

    1. To disable CRL-based certificate validation, set the enable sub-parameter of the org.wso2.carbon.identity.x509Certificate.validation.validator.CRLValidator validator, to false.
    2. To disable OCSP-based certificate validation, set the enable sub-parameter of the org.wso2.carbon.identity.x509Certificate.validation.validator.OCSPValidato validator, to false.


    <?xml version="1.0" encoding="ISO-8859-1"?> <CertificateValidation xmlns="">
     <Validator name="org.wso2.carbon.identity.x509Certificate.validation.validator.CRLValidator" displayName="CRLValidator" enable="false">
                     <Parameter name="priority">1</Parameter>
                     <Parameter name="fullChainValidation">true</Parameter>
                     <Parameter name="retryCount">2</Parameter>
        <Validator name="org.wso2.carbon.identity.x509Certificate.validation.validator.OCSPValidator" displayName="OCSPValidator" enable="false">
                     <Parameter name="priority">2</Parameter>
                     <Parameter name="fullChainValidation">true</Parameter>
                     <Parameter name="retryCount">1</Parameter>

Disabling certificate validation in an already-started WSO2 IS pack

Follow the steps below to disable certificate validation if WSO2 Identity Server was started before.

  1. Access the WSO2 Identity Server Management Console.
  2. Click Main > Registry > Browse.
  3. Disable CRL certificate validation.
    1. Locate the CRL parameter by entering _system/governance/repository/security/certificate/validator/crlvalidator in the Location search box.
    2. Expand Properties.
    3. Click Edit pertaining to the Enable property.
    4. Change the value to false and click Save.
  4. Similarly, disable OCSP certificate validation in the _system/governance/repository/security/certificate/validator/ocspvalidator registry parameter.

For more information on CRL and OCSP certificate validation, see Configuring Certificate Revocation Validation.

Configuring the Authentication Endpoint

  1. Open the deployment.toml file in the <IS_HOME>/repository/conf/ directory.
  2. Add the following configuration to the file.

    1. authentication_endpoint : This is the URL with the port that is secured with the certificate, e.g., https://localhost:8443/x509-certificate-servlet . This value will be taken to extract the certificate from the browser by redirecting the user to the specified endpoint. Update this based on your host name.
    2. username : This attribute value will be taken as the authenticated user subject identifier. Update this with any of the certificate attributes, e.g., CN and Email.
    3. name : This attribute identifies the authenticator that is configured as the second authentication step.
    4. enable: This attribute, when set to true makes the authenticator capable of being involved in the authentication process.
    name ="x509CertificateAuthenticator"
    username= "CN"


    When X509 authentication is configured as the second authentication step, the certificate will be validated to check whether it is associated with the authenticated user in the first authentication step. For that, the username parameter will be used. For that, the authenticated user name considered in the first authentication step will be validated with the certificate attribute in this property.

    When X509 authentication is configured as the first step, this certificate attribute will be treated as the authenticated user subject identifier.

  3. If you are using the identity claim dialect URI to store X509 certificate, add the following parameter.

    setClaimURI = ""
  4. To enable storing the X509 certificate as a user claim, add the following parameter.

    EnforceSelfRegistration = true

Adding a claim mapping for the certificate

If storing the certificate as a user claim is enabled, the X509 certificate will be stored as a user claim and verified with the retrieved certificate from the request.

  1. Sign in to the WSO2 IS Management Console with one of the following URLs using admin as the username and password.

    For HTTP  --> http://<HTTP_HOST>:9776/carbon
    For HTTPS --> https://<HTTPS_HOST>:9443/carbon
  2. On the Main tab, click Claims > Add.

  3. Click Add Local Claim.
  4. Add a new claim for the certificate by giving the details as below, e.g., select a mapped attribute for the claim that is supported by the underlying database type. claim-for-certificate
  5. Click Add.

Updating the column size of the database for X509 certificates

Make note of the following points and configure your database to match your use case:

Deploying sample app

The next step is to deploy the sample app to use it in this scenario.

See the topic on deploying the sample app for information on how to configure this.

Configuring the service provider

The next step is to configure the service provider.

  1. Return to the management console.
  2. In the Service Providers section under the Main tab, click Add.
  3. Since you are using Travelocity as the sample, enter in the Service Provider Name text box and click Register.
  4. In the Inbound Authentication Configuration section, click Configure under the SAML2 Web SSO Configuration section.
  5. Now set the configuration as follows:
    1. Issuer :
    2. Assertion Consumer URL : http://localhost:8080/
  6. Select the following check-boxes:

    1. Enable Response Signing.
    2. Enable Single Logout.
    3. Enable Attribute Profile.
    4. Include Attributes in the Response Always.


  7. Click Update to save the changes. Now you will be sent back to the Service Providers page.

  8. Go to the Local and Outbound Authentication Configuration section.
  9. You have two options here. You can add X509 certificate authenticator as the first factor and also as the second factor.

    1. Second factor

      1. Select the Advanced configuration radio button option.

      2. Add the basic authentication as a first step and X509Certificate authentication as the second step.

    2. First factor

      • Select Local Authentication as the Authentication Type and select X509Certificate from the drop-down list.
      • When using X509 as first step authentication, you need to create a user in IS management console with the Email provided while creating the browser certificate.


        For more information on creating users and assigning roles using management console, refer here.

  10. Finally, click on Update to finish the service provider configurations.

You have now added and configured the service provider.

Configuring CRL Caching

CA provides a CRL that is valid for a limited duration, which is defined in the Next Update CRL field. This field indicates the date by which the next CRL will be issued. According to the Internet X.509 PKI Certificate and CRL Profile , the next CRL could be issued before but not later than the indicated date. This property is considered to validate the returned CRL from cache as a certificate in the CRL can be temporarily invalidated (Hold) rather than being irreversibly revoked, i.e., an outdated CRL creates a security exposure.

The X509CRL is downloaded from the CRL URL and persisted in cache. Follow the steps below to configure CRL caching.

  1. Open the deployment.toml file located in the <IS_HOME>/repository/conf/ directory.
  2. Add the following configuration.


Import certificate

  • Chrome

    1. In your browser, navigate to Settings > HTTPS/SSL > Manage certificates.
    2. Click on Import, select the localhost.p12 file, and then click Open. Note that you may have to enter the password that you used to generate the p12 file, (browserpwd) to open it.
  • Firefox

    1. Click on the menu option on the right of the screen and select Preferences.


    2. Click Privacy & Security in the left navigation and scroll down to the Certificates section. Click View Certificates.

      view-certificates 3. In the window that appears, click Import.
      import-firefox 4. Select the localhost.p12 file, and then click Open. Note that you may have to enter the password that you used to generate the p12 file, (browserpwd) to open it.

Testing the sample

  1. To test the sample, go to the following URL: http://<TOMCAT_HOST>:<TOMCAT_PORT>/ E.g., http://localhost:8080/
  2. Click the link to log in with SAML from WSO2 Identity Server.


    If you have set this up as the first factor you will not get basic authentication.


  3. The basic authentication page appears unless it is not set as the first factor. Use your username and password and click Sign In (Only for the second step).

  4. You are directed to the X509 certificate authentication page ( https://localhost:8443/x509-certificate-servlet ). If the authentication is successful, you will be taken to the home page of the app.

Extending the authenticator

Now that you have learned how to configure the authenticator, let's learn how to extend its functionality for additional authentication methods.

  • Authenticating using the Subject Alternative Name
  • Authenticating using the RDN

Authenticating using the Subject Alternative Name

About Subject Alternative Name

The Subject Alternative Name (SAN) is an extension to the X.509 certificate format that enables securing multiple hostnames such as CN, IP, DNS and email, using a single certificate.

How SAN works in WSO2 Identity Server

  • If SAN is not enabled, the system does not check for alternative names in the certificate.
  • If SAN is enabled with either of the following, the system throws an error fails the authentication process:
    • Alternative names are not defined in the certificate.
    • No matching string is found for the alternative name pattern that is defined in the certificate.
    • There are multiple matching strings found for the alternative name pattern that is defined in the certificate.
  • If SAN is enabled where a single match is found for the alternative name pattern that is defined in the certificate, that match is used as the user name and the system begins user authentication. When a user with the given user name is found in the system, the user gets authenticated.ated.

To enable SAN in WSO2 Identity Server, add the following configurations to the deployment.toml file in the <IS_HOME>/repository/conf/ directory.


Authenticating using the RDN

  • Relative Distinguished Name (RDN)
    An RDN comprises one or more certificate attribute-value pairs in the form of <attribute>=<value>.

    Sample RDN

    cn=John Doe+o=WSO2

    In the above example, the two attribute-pairs, cn=John Doe and c=US are separated by a plus (+) sign.

  • Distinguished Name (DN)
    A DN is a sequence of comma-separated RDNs, i.e., RDNs are the components of a DN.

    Sample DN

    cn=Jon Doe+o=WSO2, c=US

How DN/RDN works in WSO2 Identity Server

When this is configured, the system checks for a matching string from the subject DN. Once found, it is used as the user name to proceed with user authentication. If more than one matching values or no matching values are found, the system throws an error and fails the authentication process.

To enable subject DN in WSO2 Identity Server, add the following configuration to the deployment.toml file in the <IS_HOME>/repository/conf/ directory.