The backend has been there since d4b49b9 with nothing to click. This is the
half a person actually touches.
A card under a new "Secrets & Access" heading on Tech Tools, which is where
somebody looks for a utility - the whole reason the plugin moved there.
THE CREATE PAGE encrypts before anything leaves the browser and shows the link
once. The plaintext is dropped from memory as soon as it is sealed, and the page
says plainly that the key is in the link and exists nowhere else, because
somebody who does not know that will paste the link somewhere durable.
THE READ PAGE IS PUBLIC, at /s/<token>, outside the app shell: the recipient
usually has no account here, so it carries no navigation and asks for no login.
Short path because the whole link gets pasted into a chat message.
IT NEVER REVEALS ON LOAD. It asks whether the link is still live, then says
"opening this destroys it" and waits for a click. A page that revealed
automatically would be burned by the first scanner that fetched it - which is
the same reason redeeming is a POST.
A MISSING FRAGMENT GETS ITS OWN MESSAGE. If a link rewriter strips the part
after the #, the recipient is told the link is missing its key and what to ask
for, rather than being shown a generic failure. That is the one failure mode
this design cannot recover from, so it is worth naming to the person looking at
it.
The client-side guards live in securesend.js and are advisory by nature - the
server cannot see plaintext, so its size limit is what enforces. They refuse a
pasted FILE outright, which removes the easiest wrong path without anyone
reading a rule, and they warn on something document-shaped: over the length a
credential needs, more than twenty lines, or starting with a PDF/zip/image
signature.
Web Crypto only, no dependency, AES-GCM so a tampered ciphertext fails to
decrypt rather than producing plausible rubbish. The key is base64url for the
fragment, which survives copy-paste and link rewriting better than the standard
alphabet.
VERIFIED THAT THE PAGES RENDER, headlessly, against the dev server: the card
appears under Secrets & Access and the create form draws with its counter and
options. NOT VERIFIED END TO END - no secret has been created, sent, opened or
decrypted, because that needs the dev API restarted and the table migrated.
