NFC Writer: Secure Tag Setup

Write NFC tags the way you actually need to — and set up secure tags that prove themselves, without paying a monthly fee. EVERYDAY NFC WRITING Write text, links, phone numbers, messages, email, locations, contacts, Wi-Fi networks, and App Store links. Read any NDEF tag and see exactly what's on it. SECURE TAGS THAT PROVE THEMSELVES (SUN) Most NFC apps stop at plain reading and writing. This one sets up SUN. A SUN tag computes a fresh signature inside the chip every time it's read, and writes it into the URL. The signing key never leaves the chip, so a copied tag can't produce a valid signature. A read counter goes up on every tap, so an old captured URL can't be replayed. That's the difference between a tag anyone can clone and a tag that proves it's the original. WHAT YOU CAN DO • Set up SUN with encrypted UID and counter, or plain mirroring • Change the factory keys to random keys…