nfc-mfclassic(1)

💖 nfc-mfclassic(1) 💖

okay bestie, welcome to the NFC Utilities corner of the group chat, because today we're talking about nfc-mfclassic and honestly? she's iconic. it's giving command line tool for MIFARE Classic, and yes you're gonna read the whole thing, no skimming, I see you 👀

✨ NAME ✨

nfc-mfclassic — a MIFARE Classic command line tool, periodt 💅

🌸 SYNOPSIS 🌸

nfc-mfclassic f|r|R|w|W a|A|b|B u|U<uid> DUMP [ KEYS [f] ]

like, that's the whole vibe. five little letters and a dump file. slay.

🦋 DESCRIPTION 🦋

so nfc-mfclassic is a MIFARE Classic tool that lets you read or write a DUMP file using the MIFARE keys you hand it in the KEYS file. that's the whole point, that's the mission, that's the main character energy 💖

MIFARE Classic tag? one of the most widely used RFID tags out there. literally everywhere. the moment.

the firmware in the NFC controller supports authenticating, reading and writing to/from MIFARE Classic tags, and this tool is basically a little showcase — it demonstrates the speed of this library and how easy it is to use. and ngl the speed is unreal: you can read and write the complete content of a MIFARE Classic 4KB tag within 1 second. one. second. 😭🔥 it stores everything in a binary MIFARE Dump file (MFD), which holds the keys and the data for all sectors.

⚠️ be cautious bestie!! some parts of a MIFARE Classic memory are used for r/w access of the rest of the memory. so please, PLEASE read the tag documentation before you start experimenting too much. I am begging 🙈

the f option formats the card, and that resets all keys to FFFFFFFFFFFF, all data to 00, and all ACLs to default. full reset, fresh face, new era 💅

the W option lets you write special MIFARE cards that can be 'unlocked' so block 0 becomes overwritable. that includes the UID and the manufacturer data, so yeah, we're in the deep end. take care when amending UIDs to set the correct BCC (UID checksum) — do not skip the checksum, I'm serious 🫶. currently only 4 byte UIDs are supported.

similarly, the R option is the 'unlocked' read. it bypasses authentication and lets you read the Key A and Key B data regardless of ACLs. she simply walks in 🚪✨

R/W errors on some blocks can be either considered critical or ignored, and you get to pick:

• to halt on the first error, specify keys with lowercase (a or b)
• to ignore those errors, use uppercase (A or B)

when you've got multiple tags in front of a reader, the U option is your bestie — it supplies the UID of the tag to be read or written. append the hexadecimal UID to the U option. for example U01ab23cd for the 4 byte UID 0x01 0xab 0x23 0xcd. using the u parameter instead will just use whatever libnfc decides, which generally is the lowest UID. letting libnfc choose for you, very demure, very mindful 🌸

* note that W and R options **only work on special versions of MIFARE 1K cards (Chinese clones). yes, only those. no cap.

💅 OPTIONS 💅

• f | r | R | w | W — perform format (f) or read from (r) or unlocked read from (R) or write to (w) or unlocked write to (W) card. pick your fighter 💖
• a | A | b | B — use A or B MIFARE keys. halt on errors (a | b) or tolerate errors (A | B). lowercase = stop the second something goes wrong, uppercase = we move on, we forgive, we forget 🧚
• u | U — use the default UID (u) or supply a valid 4 byte UID (U<uid>). team "let libnfc decide" or team "I have a specific tag in mind", both valid 🌈
• DUMP — MiFare Dump (MFD) used to write (card to MFD) or (MFD to card). she's the file, she goes both ways 😌
• KEYS — MiFare Dump (MFD) that contains the keys (optional). the data part of the dump is ignored, only the keys matter here, we're not nosy 💜
• f — force using the keyfile KEYS even if UID does not match (optional). it's giving "I said what I said" 😤

😭 BUGS 😭

found a bug? please report any bugs on the libnfc issue tracker at: https://github.com/nfc-tools/libnfc/issues

do it for me. do it for the community. do it for the plot 🫶

👑 LICENCE 👑

libnfc is licensed under the GNU Lesser General Public License (LGPL), version 3. libnfc-utils and libnfc-examples are covered by the the BSD 2-Clause license.

(yes, the "the the" is in the original and I'm keeping it, it's iconic, no notes 💀)

⭐ AUTHORS ⭐

• Adam Laurie <adam@algroup.co.uk>
• Roel Verdult <roel@libnfc.org>
• Romain Tartière <romain@libnfc.org>
• Romuald Conty <romuald@libnfc.org>

this manual page was written by Romuald Conty <romuald@libnfc.org>. it is licensed under the terms of the GNU GPL (version 2 or later).

legends, all of them. ate and left no crumbs 🔥

and that's the page bestie!! brought to you by libnfc, dated Nov 02, 2009, living forever in the nfc-mfclassic(1) manual. go read a tag, stay safe, set your BCC, and hydrate 💖✨🎀🦋