Tool

Your phone

The NFC reader you already carry — great at HF, blind to everything else.

Any phone with NFC is a decent 13.56 MHz reader and writer, and the best place to start. How phones also act as cards is covered in Phones; this page is about using one as a tool.

#Apps worth having

NXP TagInfo: tap anything and it names the chip family, the UID, the ATQA/SAK and anything readable without keys. The single most useful app on this site.
NFC Tools: reads and writes NDEF (URLs, text, Wi-Fi, contacts) and can lock tags.
NXP TagWriter: another solid NDEF writer.

#What it can't do

LF: no 125 kHz coil, so prox badges, pet chips and LF fobs are invisible. It's not an app problem.
UHF: no EPC tag reading either.
Everything on iPhone: iOS lets apps read NDEF and most common HF card types, but some (like MIFARE Classic) are off limits, and apps have to declare in advance what they'll talk to. Android is more open.

#Finding the antenna

It's usually the middle of the back on Android, and up near the top on an iPhone. Slide a card slowly across the back until it beeps, then remember the spot.

Typical spots. Phones vary, so trust the beep over the diagram.

Topics with Your phone tips

HF — 13.56 MHzOne frequency, most of the RFID you'll ever touch — payments, transit, passports, NFC, toys and badges.ConceptHF · 13.56 MHz ISO 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 MHz NFC and NDEFThe data format that makes "tap a sticker, open a link" work on every phone.Deep diveHF · 13.56 MHz MIFARE ClassicThe 13.56 MHz memory card that's in a billion transit passes, hotel keys and office badges — running a cipher that's been broken since 2008.Deep diveHF · 13.56 MHz MIFARE DESFireNXP's AES smart card — a tiny file system with a lock on every drawer. The usual right answer to "what should we migrate to?", if you manage the keys.Deep diveHF · 13.56 MHz iCLASSHID'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 MHz SeosHID'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 MHz PIV 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 AliroOne standard so any phone can be a key for any lock — tap, nearby, or hands-free.Deep dive Contactless credit cardsTap to pay is a tiny smart card doing cryptography in the half-second your card hovers over the terminal.In the wildHF · 13.56 MHz Pet 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 kHz Biohacking (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 wild Security 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 E-passportsThe chip behind the little camera-shaped logo — signed by your government, and built not to talk to strangers.In the wildHF · 13.56 MHz PhonesYour phone is a reader, a card and a wallet — sometimes all in the same minute.In the wildHF · 13.56 MHz ToysYoto cards, Skylanders, amiibo and DropMix — RFID's most fun job, done two very different ways.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 MHz NFC and NDEFThe data format that makes "tap a sticker, open a link" work on every phone.Deep diveHF · 13.56 MHz PhonesYour phone is a reader, a card and a wallet — sometimes all in the same minute.In the wildHF · 13.56 MHz