StreamFast can enable restream with tokenized HLS stream generated from an authorized token system. The user who creates such a restream should have access and control to such a token system. The user just needs to call the stream from StreamFast using a valid token parameter. StreamFast will pull the content from your source server using the requested token parameter and deliver the content. The request call of the stream from the source is illustrated below.
Client -> StreamFast (forward headers for authorization) -> Source server
As you know in HLS the primary file is .m3u8 and streams are specified as .ts in .m3u8 file. So if a client requests a stream with token, StreamFast will forward the request to source server with client information for authorization. If it is a valid client, then StreamFast will deliver the stream (.ts) from the cache.