You can select the security protocols and cryptographic algorithms that Horizon uses to encrypt communications between Horizon Client and servers, and between Horizon Client and Horizon Agent.

By default, TLS v1.1 and TLS v1.2 are enabled. SSL v2.0, SSL v3.0, and TLS v1.0 are not supported. The default cipher control string is "!aNULL:kECDH+AESGCM:ECDH+AESGCM:RSA+AESGCM:kECDH+AES:ECDH+AES:RSA+AES".

If you configure a security protocol for Horizon Client that is not enabled on the server to which the client system connects, a TLS error occurs and the connection fails.

For information about configuring the security protocols that Connection Server can accept, see the Horizon Security document.


  1. Open Settings and tap Security options.
    • If you are connected to a remote desktop or published application in full-screen mode, tap the Horizon Client Tools radial menu icon and tap the gear icon to access Settings.
    • If you are not using full-screen mode, tap Settings in the menu in the upper-right corner of the Horizon Client toolbar.
    • If you are not connected to a server, tap the Settings (gear) icon in the upper-right corner of the Horizon Client window.
  2. Tap Advanced SSL Options.
  3. Verify that Use Default Settings is deselected.
  4. To enable or disable a security protocol, tap the check box next to the security protocol name.
  5. To change the cipher control string, replace the default string.
  6. (Optional) To revert to the default settings, tap to select the Use Default Settings option.
  7. To save your changes, tap OK.


Your changes take effect the next time you connect to the server.