rfid.wtf / WTF is RFID?
Tool

USB NFC reader

A cheap desktop 13.56 MHz reader — the developer's way into HF cards, scripts and smart-card tools.

A USB NFC reader, like the long-lived ACR122U (built around NXP's PN532 chip) or the newer ACR1252U, turns a computer into an HF reader and writer. They cost little and show up to the computer as a standard PC/SC smart-card reader, so ordinary smart-card software just works.

#Handy tools

  • libnfc: nfc-list lists cards on the reader with their ATQA, UID and SAK.
  • pcsc-tools: pcsc_scan watches the reader and prints each card's ATR, a short identity string.
  • OpenSC: works with PIV and other public-key cards and can list their certificates.
  • ykman: Yubico's tool talks to a YubiKey through the reader.
  • Your own code: almost every language has a PC/SC library, which makes this the easiest way to script against cards you own.

#Limits

HF only, short range, and some readers struggle with certain card types or need a firmware quirk worked around. For LF you need a different reader, or a Proxmark3.

Topics with USB NFC reader tips

HF — 13.56 MHzOne frequency, most of the RFID you'll ever touch — payments, transit, passports, NFC, toys and badges.ConceptHF · 13.56 MHzISO 14443The standard behind almost every card you tap — how a reader finds a card, picks it out of a crowd, and starts talking.ConceptHF · 13.56 MHzPIV and CACThe US government's smart-card badge standard, and why "reads a PIV card" isn't the same as "checks a PIV card".Deep diveHF · 13.56 MHzSecurity keys (YubiKey)The thing on your keychain that logs you in with a tap — a smart card in a different shape.In the wildHF · 13.56 MHz

Where next

HF — 13.56 MHzOne frequency, most of the RFID you'll ever touch — payments, transit, passports, NFC, toys and badges.ConceptHF · 13.56 MHzISO 14443The standard behind almost every card you tap — how a reader finds a card, picks it out of a crowd, and starts talking.ConceptHF · 13.56 MHzPIV and CACThe US government's smart-card badge standard, and why "reads a PIV card" isn't the same as "checks a PIV card".Deep diveHF · 13.56 MHz