We need a table that will store a randomly generated token when an email with a link to the report is sent out to customers. We need another field to save the expiry date of the token, which will be valid for a certain period of time, maybe like 3 months to begin with. And a field that will store the slug value of the report. When a user clicks on send email button, before sending an email, we will need to store values of (slug, token, and expiry date of token) in this new table.
When a user clicks on the link in the email, we will need to verify if the token is valid for a specified slug and not expired before starting the download.