Specifications

Smart Cards Lab COMPGA12 University College London

18.1 A Simple Timing Attack Project

For this we use the following program provided to students on a ﬂash disk,

and based on a known open-source PC/SC project. The source code is

also given (so students can directly modify it by opening the .dsw ﬁle. )

To simply run it:

TimingAttackDemo.exe

which can be found in:

\Smart Cards Lab docs and free software\APDU tools\

TimingAttackDemo\sources\SCardDemo-Modif\Release\

How to use it: First open a reader and then type in an APDU com-

mand. Then press APDU button.

The timing information is displayed only in a log ﬁle, which will be

opened automatically at the end, after the program is closed by pressing

OK button.

Important: This timing attack is VERY imperfect, due to the latency

of the Windows OS, the USB port and the ﬁrmware of the smart card reader.

In order to get a precise result, one needs to repeat each command a large

number of times. this is also why it appears to freeze or it is slow.

The software provided is very simple: it can only do a loop on a single

command, it cannot execute a sequence of commands in a loop, and it

cannot power oﬀ or reset the card. Please improve it to execute sequences

of commands...

18.2 A Timing Attack on MiFare

This is just a very basic demonstration of the core principle. It does not

break MiFare authentication but shows that important timing diﬀerences

can be observed for real life products with extremely simple tools.

Here we will be executing a sequence of just two commands. It does not

matter the our tool will also repeat the ﬁrst command 100 times to have

more precise timing.

Let’s take a MiFare Classic card with a known key, for example FFFFFFFFFFFF,

that is charged into memory. Then we will authenticate for block 0. this

gives, for example

APDU: FF82200006FFFFFFFFFFFF

Resp: (90 00)

Nicolas T. Courtois 2009-10