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. Tap Settings at the bottom of the Horizon Client window.
  2. Tap Advanced SSL Options.
  3. Verify that the Reset to Default Settings option is set to off.
  4. To enable or disable a security protocol, tap the On or Off toggle 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 Reset in the upper right corner of the window.


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