LEADTOOLS provides annotation security through a number of functions. To lock annotation objects, use the AnnObject.Lock method.
When you lock an object, the password used is stored in the AnnObject.Password property.
To unlock annotation objects, use the AnnObject.Unlock method.
Use the AnnOject.IsLocked property to determine whether an object is locked. If you are interested in obscuring or blacking out a rectangular portion of an image, consider using the AnnRedactionObject class.