CCID descriptor statistics: dwMaxIFSD

Article from the serie "CCID descriptor statistics"

The dwMaxIFSD field is a number value from the USB CCID descriptor: Indicates the maximum IFSD supported by CCID for protocol T=1.

dwMaxIFSD	#	%
254	176	69.29 %
252	34	13.39 %
247	16	6.30 %
0	12	4.72 %
1024	4	1.57 %
256	3	1.18 %
1400	2	0.79 %
1041	1	0.39 %
123	1	0.39 %
2048	1	0.39 %
240	1	0.39 %
248	1	0.39 %
49	1	0.39 %
64	1	0.39 %

Some values may look strange or bogus:

• 0 is used by 5% of readers. It is not a bug for a ICCD device with a T=0 card inside because dwMaxIFSD is only used with a T=1 card.
  Readers with dwMaxIFSD = 0 are:
  • ATMEL AT91SC192192CT-USB ICCD reader
  • ATMEL AT98SC032CT-USB
  • ATMEL VaultIC420 Smart Object
  • ATMEL VaultIC440
  • ATMEL VaultIC460
  • Gemalto Hybrid Smartcard Reader
  • IID AT90S064 CCID READER
  • INSIDE Secure VaultIC 405 Smart Object
  • INSIDE Secure VaultIC 441 Smart Object
  • Inside Secure VaultIC 420 Smart Object
  • Inside Secure VaultIC 440 Smart Object
  • Inside Secure VaultIC 460 Smart Object
  • MYSMART MySMART PAD V2.0
  • SchlumbergerSema SchlumbergerSema Cyberflex Access
  • SecuTech SecuTech Token
  • TianYu CCID Key TianYu CCID SmartKey
  Among them only the MYSMART MySMART PAD V2.0 is bogus with dwMaxIFSD = 0 and dwProtocols = 0x0000 0x0300 (should be 0x0000 0x0003 for T=0 and T=1).
  
• The maximum value for dwMaxIFSD is dwMaxCCIDMessageLength - 10.
  Readers with  dwMaxIFSD > dwMaxCCIDMessageLength - 10, so bogus readers, are:
  
  • Aktiv Co., ProgramPark Rutoken Magistra
  • CCB eSafeLD
  • Feitian bR301
  • Free Software Initiative of Japan Gnuk
  • Gemalto PDT
  • Giesecke & Devrient GmbH Star Sign Card Token 550 (ICCD)
  • OCS ID-One Cosmo Card USB Smart Chip Device
  • Philips Semiconductors JCOP41V221
  • Philips Semiconductors SmartMX Sample
  • Planeta RC700-NFC CCID
  • Yubico Yubikey NEO CCID
  • Yubico Yubikey NEO OTP+CCID