RFID

RFID readers

pcscd

Is the Linux daemon to access readers compatible with the PC/SC standard.
To dump the readers list supported by libccid of your pcscd install:

 cat /etc/libccid_Info.plist|gawk '
    /ifdVendorID/{
        mode=1
    }
    /ifdProductID/{
        mode=2
    }
    /ifdFriendlyName/{
        mode=3
    }
    {
        inarray=0
    }
    /<array>/{
        i=0
    }
    /<array>/,/<\/array>/{
        inarray=1
    }
    /string/&&inarray{
        match($0,/<string>(.*)<\/string>/,a);
        t[mode i]=a[1]; 
        i++
    }
    END{
        for (j=0;j<i;j++) 
            print t[1 j]":"t[2 j], t[3 j]
    }'

Parallax

http://www.makezine.com/06/theorypractice/ => See MAKE n6

ACR122U

Intro

based on PN532

• docs
  • ISO/IEC18092 (NFC) compliant
  • NFC Tags Access Speed = 212 kbps
  • Support FeliCa card
  • Support ISO 14443 Type A & B cards
  • MIFARE® cards (Classics, DESFire)
  • SAM Socket (optional)

• To get the Firmware version string in command line: (actual string here is "ACR122U203" as the last 2 bytes are not SW1/SW2 but part of the string)

$ opensc-tool -s FF00480000
Sending: FF 00 48 00 00.
Received (SW1=0x30, SW2=0x33):
41 43 52 31 32 32 55 32 ACR122U2

You can also use scriptor:

$ echo ff00480000|scriptor           
No reader given: using ACS ACR122U PICC Interface 00 00
Using T=1 protocol
Reading commands from STDIN
> ff 00 48 00 00 
< 41 43 52 31 32 32 55 32 30 33 : Error not defined by ISO 7816

If you get the following error:

Can't allocate Chipcard::PCSC::Card object: No smartcard inserted.

that's because you've a model without SAM support. Place a tag on the reader and try again, it should work.

So that's where a lot of confusion comes into play: the two models behave very differently! see below

ACR122U-SAM

• With SAM slot
• Windows drivers & API docs

Usage:

• When there is a SAM inserted, ATR shown is the ATR of the SAM
• When there is no SAM inserted, ATR shown is a pseudo-ATR = 3B 00
• So for PCSC there is always a "card inserted"
• APDUs are sent to SAM
• To send APDUs to a contactless card, you must wrap them into pseudo-APDUs (FF 00 00 00 ...)
• To send special APDUs to the reader (to get fw or to control LEDs), just send them

Some more infos here about the Tikitag

ACR122U PICC

• Without SAM slot
• Windows drivers & API docs

Usage:

• When there is a contactless card, ATR shown is the ATR of the card
• When there is no contactless card, no ATR
• So for PCSC there is a "card inserted" if there is a contactless card
• APDUs are sent directly to the contactless card, which makes this reader fully transparent in this mode
• To send APDUs to a contactless card, you can also wrap them into pseudo-APDUs (FF 00 00 00 ...)
• To send special APDUs to the reader (to get fw or to control LEDs)
  • If there is a contactless card, just send the APDUs
  • If there is no contactless card, the CCID Escape command must be used (*)

(*) Here is one small example how to use the Escape command:

#!/usr/bin/python
from smartcard.scard import *
hresult, hcontext = SCardEstablishContext( SCARD_SCOPE_USER )
hresult, hcard, dwActiveProtocol = SCardConnect(
hcontext, 'ACS ACR122U PICC Interface 00 00', SCARD_SHARE_DIRECT, SCARD_PROTOCOL_T0 )
IOCTL_SMARTCARD_VENDOR_IFD_EXCHANGE = SCARD_CTL_CODE(1)
CMD = [0xFF, 0x00, 0x48, 0x00, 0x00]
hresult, response = SCardControl( hcard, IOCTL_SMARTCARD_VENDOR_IFD_EXCHANGE, CMD )
if hresult!=SCARD_S_SUCCESS:
     raise error, 'Failed to control: ' + SCardGetErrorMessage(hresult)
print ''.join([chr(i) for i in response])

This requires also to allow libccid to use the Escape command, you've to set bit 0 of ifdDriverOptions in /etc/libccid_Info.plist to 1:

       <key>ifdDriverOptions</key>
       <string>0x0001</string>