Scan a tag

Hex NFC reads a tag in one tap. You tap Scan, hold the tag against the top of your iPhone, and the app shows which chip it found and what the tag holds. A scan only reads, so nothing on the tag changes.

A tag can also be set to require its password before it will be read. A tag protected that way refuses to be read until the password is presented. Presenting it takes two taps rather than one. The second half of this page covers that. Most protected tags are write-protected only. Those scan in one tap like any other tag. If you have not scanned a tag before, Read your first tag covers the same tap from the start.

Scan a tag

1. Step 1Open the scan screen

   Open Hex NFC and tap Scan on its home screen. The scan screen opens and reads "Hold tag against the top of your iPhone".

2. Step 2Hold the tag against the top of your iPhone

   Rest the top edge of your iPhone on the tag and keep it still. The screen reads "Reading…" while the tag is read.

3. Step 3Read what the app found

   "Tag detected" appears with a tick, and the chip's name sits under it. Below that the app says what it read. The line "1 record found" gives the number of records on the tag. "No NDEF records on this tag" means the tag is formatted but empty. The tag's UID is last.

The result holds for about a second, then the app opens Tag with the records listed, where you can change them or write them again. Nothing from the result is lost there. The chip's name is the heading of the tag info card, and the records are the list below it. The UID is a row on that card, where a tap copies it at any time. Each scan is saved to your history as well. See Find a tag you scanned before and Edit a tag's records.

Some tags leave the scan screen by another route. A Japanese transit card opens its own read-only result, covered in Read a transit card. An electronic passport asks for the details on its photo page first, covered in Read a passport. A protected tag asks for its password, which is the next task here.

If the result says "This tag isn't formatted yet", nothing you write to the tag will be readable until the tag is formatted. Erase or format a tag says how to do that.

Unlock a protected tag

A tag that requires its password to be read stops the scan. The scan screen shows "Tag is protected" above this sentence: "This tag looks password-protected. Enter its password, then hold it to the top of your iPhone again." Under that sit the password field, Unlock & scan again, and a row holding Cancel and Try again. The password belongs to the tag, not to an account, and only the person who set it has it. The setting that produces this state is Also require password to read, covered in Protect a tag with a password.

1. Step 1Enter the tag's password

   In Tag password (4 bytes), enter the password as hexadecimal characters, 0 to 9 and A to F. A 4-byte password is 8 characters: type it as A1B2C3D4 or as A1:B2:C3:D4, because the colons between the bytes are optional and do not count towards the length. The note under the field reads "OK" once the entry is the right length. On an NTAG424 DNA the field reads Tag key (16-byte AES) instead. On a MIFARE Ultralight C it reads Tag key (16-byte 3DES). Those two chips open with a key, not a password. Both of those keys are 16 bytes, which is 32 characters.

2. Step 2Start the second tap

   Tap Unlock & scan again. The button stays dim until what you entered is the right length for the chip.

3. Step 3Hold the tag against the top of your iPhone again

   The app presents the password, then reads the tag and shows "Tag detected" as it does for any other tag.

A password the tag refuses brings you back to "Tag is protected", with the prompt replaced by "That password didn't unlock the tag. Check it and try again." On an NTAG424 DNA or a MIFARE Ultralight C it reads "That key didn't unlock the tag. Check it and try again." instead. Correct the entry and tap Unlock & scan again for another tap. A refused password stops the chip answering for the rest of that tap. Every attempt is a fresh tap by design. To go back to an ordinary read with no password, tap Try again. Cancel does something else: it closes the scan screen without reading the tag, and what you typed is discarded. Neither one changes the tag.

Unlock a protected tag before writing to it

A write starts on Tag. A protected tag reaches Tag through the unlock above. Finish that scan first, and the app opens Tag as it does for any other tag. Two routes skip that read. In Library, the History tab lists the tags you have scanned before, and a tap on a row re-opens that tag on Tag. A swipe of a preset from the left, on the Presets tab, offers Write, which opens the write screen straight away against the preset's records.

On Tag, tap Write in the toolbar and the write screen opens. Write a link to a tag covers a write from end to end; what follows is the extra step a protected tag adds.

The write screen asks for the password again, even on a tag you unlocked a moment ago. Each tap is a separate session, and the app carries no password across one. Typing it a second time is expected, not a sign the unlock failed. Counted from a standing start, a protected tag takes three taps: the scan it refuses, the unlock scan that opens Tag, and the write. The screen shows "Tag is protected", then asks for the password: "This tag is password-protected. Enter its password to write to it, then hold it to the top of your iPhone again."

1. Step 1Enter the password on the write screen

   In Tag password (4 bytes), enter the tag's password, the same 8 hexadecimal characters a scan asks for. The field names a key instead of a password on the two chips that use one, and a key is 32 characters.

2. Step 2Start the write's second tap

   Tap Unlock & write. If the write also changes the tag's protection, the button reads Unlock & continue instead. The app then shows you the tag's UID and asks you to type it in, under "Type this tag's UID to confirm.", before it writes. See Protect a tag with a password.

3. Step 3Hold the tag to write it

   Hold the tag against the top of your iPhone again. The app presents the password and then writes.

A refusal here reads "That password didn't unlock the tag. Check it and try again." as well, and is answered the same way: check what you entered, then hold the tag again.

A scan can end in "Scan failed". A tag you believe is blank might ask for a password. Either way, work through If a tag does not scan or write.