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 only you hold • Verify a tag is genuine — signature and replay check • Inspect how a secure tag is configured, no keys required • Set up tags in batches, with duplicate detection • Diagnose authentication and the secure channel step by step VERIFICATION RUNS ON YOUR DEVICE No account. No server. No ads. No analytics. No tracking. Your keys are stored in the iOS Keychain and sync through iCloud — they never reach us, because there is no "us" to reach. Verification works offline, which matters in a warehouse, a customs hall, or a venue with no signal. PRICING WITHOUT A SUBSCRIPTION Reading, writing, inspecting, and verifying are always free, and there are no ads anywhere in the app. Set up your first secure tag for free, so you can confirm the whole thing works on your own hardware before paying anything. After that, Secure NFC Pro unlocks secure setup for good — one payment, no subscription, no renewals. If a setup stops partway and leaves a tag half-configured, finishing that tag is free. The app started the change, so the app finishes it. REQUIREMENTS • iPhone 7 or later with iOS 17 • Tags that support SUN for the secure features • Basic reading and writing work with any NDEF tag NOTE ON WI-FI TAGS Wi-Fi credentials are written to the standard Wi-Fi Simple Configuration format. iOS does not support automatic joining, so tapping the tag shows the network details instead of connecting. CHANGING KEYS IS PERMANENT These chips have no factory reset. If you lose a tag's keys, that tag can never be reconfigured. The app makes you confirm you've backed up your keys before it writes them, and keeps both the old and new keys until a change completes.