Friday, June 7, 2013

CCID descriptor statistics: bInterfaceClass

Article from the serie "CCID descriptor statistics"

The bInterfaceClass field is a number value from the USB descriptor: Class code (assigned by the USB-IF).
A value of zero is reserved for future standardization.
If this field is set to FFH, the interface class is vendor-specific.
All other values are reserved for assignment by the USB-IF.

0x0B [Chip Card Interface Device Class (CCID)]24094.49 %
0xFF145.51 %

The CCID 1.1 specification gives/imposes the value 0Bh. FFh is for proprietary devices.

As with the bDescriptorType field it is not suprising that thevast majority of devices use the standardized value 0Bh.

The 14 devices with bInterfaceClass = 0xFF are:
  • Cherry GmbH SmartTerminal ST-2xxx
  • Dell keyboard SK-3106
  • Gemalto Gem e-Seal Pro USB Token
  • NTT Communications Corp. SCR3310-NTTCom USB SmartCard Reader
  • OCS ID-One Cosmo Card USB Smart Chip Device
  • SCM Microsystems Inc. SCR 331-DI
  • SCM Microsystems Inc. SCR331-DI USB Smart Card Reader
  • SCM Microsystems Inc. SDI010 Smart Card Reader
  • SCM Microsystems Inc. SDI011 Contactless Reader
  • SCM Microsystems Inc. SPR 532
  • SchlumbergerSema SchlumbergerSema Cyberflex Access
  • Verisign Secure Storage Token
  • Verisign Secure Token