ACR122U

A cheap PC/SC 13.56 MHz reader driven by libnfc. Covers HF/NFC recon without the Proxmark3's price tag.

30€ RFID & NFC

NFC photo coming soon

What it does

The ACR122U is an inexpensive USB PC/SC reader for 13.56 MHz (HF) tags, driven from Linux by libnfc's tools (nfc-list, nfc-mfclassic) and by mfoc/mfcuk for MIFARE Classic key recovery. It has no low-frequency antenna and no card-emulation mode, so it covers the everyday HF read/dump/write loop at a fraction of a Proxmark3's cost.

Use cases

Enumerate a tag

List the UID, ATQA and SAK of any 13.56 MHz card placed on the reader.

Recover keys with mfoc/mfcuk

Run the nested attack once one key is known, or darkside when none is, then dump the card.

Write a dump to a magic card

Push a recovered dump, UID included, onto a gen1a/gen2 blank.

How you use it

Talk to it through libnfc; mfoc/mfcuk lean on the same driver for key recovery:

nfc-list                              # enumerate a tag on the reader
mfoc -O dump.mfd                      # nested attack, needs at least one known key
nfc-mfclassic W a blank.mfd dump.mfd  # write the dump onto a magic UID-writable card

Variants & pitfalls

The kernel driver fights libnfc. Linux's built-in pn533 driver grabs the reader before libnfc can. Blacklist it (or unbind the device) or every libnfc command sees no device.

HF only. It never sees a 125 kHz LF badge; that needs a Proxmark3 or a dedicated LF reader.