# NFC Writer: Secure Tag Setup — Read, write & verify NFC tags

> Read, write & verify NFC tags (iPhone/iPad app by Juyeon Yu.)

- Source: https://appshunter.io/ios/app/nfc-writer-secure-tag-setup/id6803492972 (this page in markdown: same URL + `.md`)
- Developer: [Juyeon Yu](https://appshunter.io/developer/1499305185)
- Category: Utilities, Developer Tools
- Price: Free
- Age rating: 4+
- Requires: iOS 17.0 · 2 MB
- Languages: American English
- Released: 2026-09-17
- Data updated: 2026-09-26
- User reviews in markdown: https://appshunter.io/ios/app/nfc-writer-secure-tag-setup/id6803492972/reviews.md

## What is NFC Writer?

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.


## Version history (last 1 release)

### 1.0 — 2026-09-17

No release notes.

## More apps by Juyeon Yu

- [뉴스스크랩](https://appshunter.io/ios/app/id1499305186)
- [내 차를 찾아줘](https://appshunter.io/ios/app/id1544991756)
- [두두](https://appshunter.io/ios/app/id6449709551)
- [count!!](https://appshunter.io/ios/app/count/id6670269897)
- [한눈에 대출계산기](https://appshunter.io/ios/app/id6739780797)
- [너와의하루](https://appshunter.io/ios/app/id6744867825)

All apps by Juyeon Yu: https://appshunter.io/developer/1499305185

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-26.*