I tried using example https://developers.cloudflare.com/stream/viewing-videos/securing-your-stream/#
I tried using example https://developers.cloudflare.com/stream/viewing-videos/securing-your-stream/#option-2-generating-signed-tokens-without-calling-the-token-endpoint but won't work

Cloudflare Docs
By default, videos on Stream can be viewed by anyone with just a video id. If you want to make your video private by default and only give access to certain users, you can use the signed URL feature. When you mark a video to require signed URL, it can no longer be accessed publicly with only the video id. Instead, the user will need a signed url...


