Electronics notes/RFID and NFC notes
Contents
RFID, NFC, contactless smart cards
| This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me) |
RFID (Radio-frequency identification) refers to a radio-frequency communication.
It often refers to a few specific designs, most of which are small and fairly easily hidden, particularly in/on/as small surfaces, relatively hidden devices.
On power
There are:
- passive tags
- which use an external source of power - often the communication itself (the reason for the large coiled antennae?)
- can be very small and thin, and therefore almost invisibly embedded in many things.
- common, because you don't need to care about power at all
- active tags
- battery-powered (...so limited lifespan and more expensive)
- can signal autonomously
- can be used over considerably larger distances
- can often communicate faster
- battery assisted passive (BAP)
- active tags that take negligible power from their batteries until triggered by communication
- cannot signal autonomously
Frequency use
| This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me) |
Sorted approximately by common use:
- Low-frequency - 120-150kHz range
- for many countries often specifically ~125 or ~134.2 kHz
- these are more or less interchangeable
- You can fairly easily get readers (and writers) for this.
- High-frequency - 13.56 MHz (worldwide ISM(verify))
- Used in access badges, bank cards, library cards, loyalty cards, etc.
- Example: Mifare (which is sometimes known for )
- Ultra-high
- 433MHz
- 868MHz (EU unlicensed) and ~915MHz (US unlicensed) (think ISM)
- Microwave
- 2.4Hz and 5GHz - expensive tags
In term of 'what's in your wallet', it's probably mostly ~125 / ~134 kHz, and 13.56 MHz (verify)
Security criticism
RFID/NFC blocking wallet
Notes on cards and protocols
| This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me) |
Proximity card
Early proxcards hold about as little as a magnetic stripe card.
Originally and mainly passive cards (typically at 125kHz, and correlated with ISO 7810 ID-1 sized cards),
powered by the reader so must be held close.
Active proxcards have a battery (lifetime generally on the order of a few years), and may be contacted at 2 meters or so, and a few more, useful for things like automated toll collection, gate opening, and such.
T5557
EM4100
Unsorted
NFC
NDEF
Contactless smart card
Seems to refer to cards with
- a read-only CSN/UID
- a read-write IC
- some basic security
- usually in a ISO 7810 sized card (but also in keyfobs, etc.)
...which makes them a little more complex than classic proxcards.
Typically at 13.56 MHz ('RFID HF')
Protocols vary, but MiFare is one of the largest.
See
- ISO 14443 - proximity cards at 13.56MHz
- Type A and Type B, same protocol but varying modulation, coding, init
- ISO 15693 - vicinity cards (~1meter) at 13.56MHz
- ISO 18000 - varied systems at different frequencies
- below 135kHz
- at 13.56MHz
- at 2.45GHz
- within 860MHz .. 960MHz
- at 433MHz
https://en.wikipedia.org/wiki/Contactless_smart_card
Biometric passports
EMV
Contactless payment
The acronym originally stood for its creators, "Europay, Mastercard, and Visa" https://en.wikipedia.org/wiki/EMV
MiFare
https://en.wikipedia.org/wiki/MIFARE
NFC tags
Security
Calypso
https://en.wikipedia.org/wiki/Calypso_(electronic_ticketing_system)
CIPURSE
https://en.wikipedia.org/wiki/CIPURSE
EU identity cards
https://en.wikipedia.org/wiki/National_identity_cards_in_the_European_Economic_Area
