QR code transfer

How it works

The code is a picture of a link. It does not carry the file. Anyone who can see the code can use a public URL inside it. Expiry and a password still apply. Phones scan well. Desktop cameras scan badly.

A gallery prints a code that points at a 48-hour link to a 200 MB lookbook. Guests scan and download. A photo of the poster posted online keeps working until expiry. A permanent public URL in the code would have kept working all year.

How it differs

A QR code is not AirDrop. It needs a network path to the host in the URL.

Tiny codes that encode a long signed URL fail to scan.

Test print size.

On the ticket

• The practical close is a log line: time, actor, byte count, result.
• Without that line the transfer is a story.
• With it, the next person can see whether this door did what the ticket claimed.
• If the path is shared, say so in the partner profile so a later change does not silently pick a different limit, key, or region.
• On a real ticket, write down the door, the byte count, and the clock.
• For qr code transfer, that means naming the host or bucket, the expected size, and the time the other side must have a complete file.
• A progress bar is not that record.
• A 200 response that arrives before the complete call is not that record.
• If a retry is allowed, say how many and whether it resumes.
• If a person must approve the send, name the person.
• Partners who receive qr code transfer files should match on hash or size before they import.
• A same-length corrupt file passes a size check and fails a hash.
• Keep the published hash off the only channel an attacker can edit, or treat it as a corruption check rather than a substitution check.
• When the path changes, new key, new region, new cap, update the profile the same day so the next run does not use a stale limit.