CCID descriptor statistics: bDescriptorType

Article from the serie "CCID descriptor statistics"

The bDescriptorType field is a number value from the USB CCID descriptor: Functional Descriptor type.

bDescriptorType # %
0x21 249 98.03 %
0xFF 5 1.97 %

The CCID 1.1 specification gives/imposes the value 21h. FFh is for proprietary devices.
It is then not suprising that thevast majority of devices use the standardized value 21h.

The 5 devices with bDescriptorType = 0xFF are:
  • Dell keyboard SK-3106
  • Gemalto Gem e-Seal Pro USB Token
  • Verisign Secure Storage Token
  • Verisign Secure Token