rfid.wtf / WTF is RFID?
Tool

Flipper Zero

The pocket multi-tool with a dolphin on the screen — 125 kHz and NFC in a friendly menu.

The Flipper Zero is a small handheld with a screen, a D-pad and a lot of radios: 125 kHz RFID, NFC (13.56 MHz), Sub-GHz radio, infrared, iButton and GPIO pins. Everything sits behind a menu with a cartoon dolphin, which makes it the friendliest way to start poking at your own cards.

#For RFID

  • 125 kHz RFID → Read: identifies common LF families (EM4100, HID Prox, Indala, FDX-B animal tags…) and shows the data.
  • NFC → Read: identifies HF cards, shows the ATQA, SAK and UID, and reads whatever is readable without keys, including NDEF on stickers.
  • The antennas are on the back: LF near the middle, NFC near the top. Hold cards flat against it.

#Limits worth knowing

  • No UHF RFID. The Sub-GHz radio covers some of the right frequencies, but it doesn't speak the EPC Gen2 protocol. For clothing tags you need a UHF reader.
  • Range is short, especially on LF. Move the card around slowly.
  • It's a generalist. For deep protocol work, people graduate to a Proxmark3.

Topics with Flipper Zero tips

LF — 125 kHzThe old, slow, everywhere band — badges, pet chips and car keys, read from a few centimetres by a coil with hundreds of turns.ConceptLF · 125–134 kHzHF — 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 MHzHID ProxThe beige 125 kHz badge on half the office lanyards in North America. It shouts one fixed number and does no crypto at all.Deep diveLF · 125–134 kHziCLASSHID's 13.56 MHz access family, in three acts — broken legacy iCLASS, the SR migration card, and the modern SE platform. What ties the new ones together is the SIO.Deep diveHF · 13.56 MHzSeosHID's current flagship credential — standards-based AES, carried in an SIO, and the same thing whether it's a card, a fob or the key in your phone.Deep diveHF · 13.56 MHzPet microchipsA grain-of-rice LF tag that says one number. Whether it gets your pet home depends entirely on a database.In the wildLF · 125–134 kHzBiohacking (human implants)The same grain-of-rice glass chip as the dog, injected into the web of your hand. A hobbyist access badge you can't lose — and can't upgrade without a scalpel.In the wildPhonesYour phone is a reader, a card and a wallet — sometimes all in the same minute.In the wildHF · 13.56 MHzToysYoto cards, Skylanders, amiibo and DropMix — RFID's most fun job, done two very different ways.In the wildHF · 13.56 MHz

Where next

LF — 125 kHzThe old, slow, everywhere band — badges, pet chips and car keys, read from a few centimetres by a coil with hundreds of turns.ConceptLF · 125–134 kHzHF — 13.56 MHzOne frequency, most of the RFID you'll ever touch — payments, transit, passports, NFC, toys and badges.ConceptHF · 13.56 MHz