You can create a shared secret as part of the process of creating a Form Fill or Identity Injection policy. You can also create a shared secret independent of a policy.
Click Devices > Identity Servers, then click Shared Settings > Custom Attributes.
Click New in the Shared Secret Names section and specify the following details:
Secret Name: Specify a display name for the shared secret.
Secret Entry Name. Specify an attribute name for a value you want to store.
Click OK.
Identity Server creates and encrypts the object.
To create additional attributes to store values, click the secret name, click New, specify a name, then click OK.
Click OK.