Classic Electronics Smart 4F Especificaciones descargar pdf (Pagina 17)

Smart Cards Lab COMPGA12 University College London

9 Unique ID for RFID Tags:

It is ﬁxed, usually stored in the ﬁrst block, that is read-only, and can never

be changed. This read-only feature is currently the main reason why a blank

card cannot be used as a clone of an Oyster card (all the other data can be

copied).

Motto: software cannot be protected by software.

cd C:\Program Files\rfidiot

cardselect.py

Example 1: Your Oyster Card UID:

Example 2: Your university smart card UID:

9.1 Electronic Passports

Thing are not exactly the same with electronic passports.

Depending on the country the UID will be ﬁxed, random, or will be

random and start with 08.

Your own passport:

Country: , issued: ,

⇒ UID is

10 Further Identiﬁcation

In many cards it is diﬃcult to change the unique ID that is written in the

part of memory that can never be modiﬁed.

In addition it may be possible to further prove the authenticity of the

smart card data by a cryptogram or a digital signature, similar to the SDA

mechanism in bank cards. In fact typically the unique ID of the card that

is returned by cardselect.py or by the standard command GET CARD SE-

RIAL NUMBER we exploit later, is too short to achieve this goal (typically

4 bytes, sometimes 6). Thus it is necessary to have longer authentication

data in smart cards. A full-ﬂedged digital signature with public third-party

veriﬁability requires at least 320 bits, and frequently much more.

Another point is that counterfeit smart card chips exist in large quan-

tities. It is important to be able to know which smart cards are genuine,

Nicolas T. Courtois 2009-10

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Classic Electronics Smart 4F Especificaciones Pagina 17