If I use a link like this:
Will the infomation be safe?
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If you only access it over HTTPS, then TLS/SSL will protect the URL from eavesdroppers on the connection.
However, the secret URL can leak by other means. For example, if the page is HTML content and contains links or references to any external sources, then the URL will be leaked in the
referer HTTP header.
Also, once the link is known it can be bookmarked, meaning there is no way to revoke access without changing the URL. If the link is posted anywhere else, it could also end up on search engines.
Finally, any directory browsing or path traversal vulnerabilities on your server could reveal the path.