The issue security scheme allows you, as an end user, to control who can access individual issues, based on the security levels set. Issues with the security level can only be viewed by those who meet the criteria. Note that the subtasks inherit security levels from their parent issues.

Once we have applied the issue security scheme to a project, users with the Set Issue Security permission are able to select a security level while creating and editing issues, as shown in the following screenshot:

It is also worth mentioning that you can only select security levels that you belong to. For example, if there are two security levels, A and B, then security level A is granted to the jira-administrators group, and security level B is granted to the jira-users group. Now, as a member of the jira-users group, you will only be able to select security level B. This is to prevent users from accidentally locking themselves out of an issue by selecting the wrong security level.

A user who meets the criteria for the selected security level is able to view the issue normally. However, if a user who does not meet the criteria tries to view the issue, they get a permission violation error, as shown in the following screenshot:

This message also informs users that the may have been deleted.