How do educational and training institutions generally protect their PPT or courseware from being copied by students at will? (Extended question: How to prevent courseware from being stolen by teachers) Courseware content can be converted into PDF format, and then encrypted and protected by the technology of interconnected PDF. You can set different access rights for different people, such as whether you can see all pages or specify pages, whether you can copy content, whether you can edit and modify content, whether you can print it, and whether you can specify the expiration time of content. All these permission settings are dynamic, and you can modify or revoke the authorization at any time. There are many functions like this. You can trust me personally, or you can check online yourself.