Configuring TLS

Learn how to configure Keycloak's https certificates for ingoing and outgoing requests as well as mTLS.

Transport Layer Security (short: TLS) is crucial to exchange data over a secured channel. For production environments, you should never expose Keycloak endpoints through HTTP, as sensitive data is at the core of what Keycloak exchanges with other applications. In this guide, you will learn how to configure Keycloak to use HTTPS/TLS.

Configuring TLS in Keycloak

Keycloak can be configured to load the required certificate infrastructure using files in PEM format or from a Java Keystore. When both alternatives are configured, the PEM files takes precedence over the Java Keystores.

Providing certificates in PEM format

When you use a pair of matching certificate and private key files in PEM format, you configure Keycloak to use them by running the following command:

bin/kc.[sh|bat] start --https-certificate-file=/path/to/certfile.pem --https-certificate-key-file=/path/to/keyfile.pem

Keycloak creates a keystore out of these files in memory and uses this keystore afterwards.

Providing a Java Keystore

When no keystore file is explicitly configured, but http-enabled is set to false, Keycloak looks for a conf/server.keystore file.

As an alternative, you can use an existing keystore by running the following command:

bin/kc.[sh|bat] start --https-key-store-file=/path/to/existing-keystore-file

Setting the Keystore password

You can set a secure password for your keystore using the https-key-store-password option:

bin/kc.[sh|bat] start --https-key-store-password=<value>

If no password is set, the default password password is used.

Configuring TLS protocols

By default, Keycloak does not enable deprecated TLS protocols. If your client supports only deprecated protocols, consider upgrading the client. However, as a temporary work-around, you can enable deprecated protocols by running the following command:

bin/kc.[sh|bat] start --https-protocols=<protocol>[,<protocol>]

To also allow TLSv1.2, use a command such as the following: kc.sh start --https-protocols=TLSv1.3,TLSv1.2.

Switching the HTTPS port

Keycloak listens for HTTPS traffic on port 8443. To change this port, use the following command:

bin/kc.[sh|bat] start --https-port=<port>

Using a truststore

In order to properly validate client certificates and enable certain authentication methods like two-way TLS or mTLS, you can set a trust store with all the certificates (and certificate chain) the server should be trusting. There are number of capabilities that rely on this trust store to properly authenticate clients using certificates such as:

  • Mutual-TLS Client Authentication

  • End-User X.509 Browser Authentication

You can configure the location of this truststore by running the following command:

bin/kc.[sh|bat] start --https-trust-store-file=/path/to/file

Note that this trust store is targeted for authenticating clients where Keycloak is acting as a server. For configuring a trust store where Keycloak is acting as a client to external services through TLS, please consider looking at the Configuring trusted certificates for outgoing requests guide.

Setting the truststore password

You can set a secure password for your truststore using the https-trust-store-password option:

bin/kc.[sh|bat] start --https-trust-store-password=<value>

If no password is set, the default password password is used.

Securing credentials

Avoid setting a password in plaintext by using the CLI or adding it to conf/keycloak.conf file. Instead use good practices such as using a vault / mounted secret. For more detail, see the Vault Guide / Production deployment guide.

Enabling mutual TLS

Authentication using mTLS is disabled by default. To enable mTLS certificate handling when Keycloak is the server and needs to validate certificates from requests made to Keycloaks endpoints, put the appropriate certificates in Keycloaks truststore and use the following command to enable mTLS:

bin/kc.[sh|bat] start --https-client-auth=<none|request|required>

Using the value required sets up Keycloak to always ask for certificates and fail if no certificate is provided in a request. By setting the value to request, Keycloak will also accept requests without a certificate and only validate the correctness of a certificate if it exists.

Be aware that this is the basic certificate configuration for mTLS use cases where Keycloak acts as server. When Keycloak acts as client instead, e.g. when Keycloak tries to get a token from a token endpoint of a brokered identity provider that is secured by mTLS, you need to set up the HttpClient to provide the right certificates in the keystore for the outgoing request. To configure mTLS in these scenarios, see the Configuring outgoing HTTP requests guide.

Relevant options

Type Default

http-enabled

Enables the HTTP listener.

CLI: --http-enabled

Env: KC_HTTP_ENABLED

true, false

false

https-certificate-file

The file path to a server certificate or certificate chain in PEM format.

CLI: --https-certificate-file

Env: KC_HTTPS_CERTIFICATE_FILE

https-certificate-key-file

The file path to a private key in PEM format.

CLI: --https-certificate-key-file

Env: KC_HTTPS_CERTIFICATE_KEY_FILE

https-cipher-suites

The cipher suites to use.

If none is given, a reasonable default is selected.

CLI: --https-cipher-suites

Env: KC_HTTPS_CIPHER_SUITES

https-client-auth

Configures the server to require/request client authentication.

CLI: --https-client-auth

Env: KC_HTTPS_CLIENT_AUTH

none, request, required

none

https-key-store-file

The key store which holds the certificate information instead of specifying separate files.

CLI: --https-key-store-file

Env: KC_HTTPS_KEY_STORE_FILE

https-key-store-password

The password of the key store file.

CLI: --https-key-store-password

Env: KC_HTTPS_KEY_STORE_PASSWORD

password

https-key-store-type

The type of the key store file.

If not given, the type is automatically detected based on the file name.

CLI: --https-key-store-type

Env: KC_HTTPS_KEY_STORE_TYPE

https-port

The used HTTPS port.

CLI: --https-port

Env: KC_HTTPS_PORT

8443

https-protocols

The list of protocols to explicitly enable.

CLI: --https-protocols

Env: KC_HTTPS_PROTOCOLS

TLSv1.3

https-trust-store-file

The trust store which holds the certificate information of the certificates to trust.

CLI: --https-trust-store-file

Env: KC_HTTPS_TRUST_STORE_FILE

https-trust-store-password

The password of the trust store file.

CLI: --https-trust-store-password

Env: KC_HTTPS_TRUST_STORE_PASSWORD

https-trust-store-type

The type of the trust store file.

If not given, the type is automatically detected based on the file name.

CLI: --https-trust-store-type

Env: KC_HTTPS_TRUST_STORE_TYPE

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