cryptography and copy protection

X etc 12 rennes presentation typical use of card for

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: use of card for s/w protection 7 label b 6 code of g encrypted 5 call g(11) 4 label a 3 code of f encrypted 2 call f(41) 1 send the encrypted code of f to the USB token USB token decrypts code and sends ready signal 3 = order of exection 13 send parameter 11 to the token collect f(41) and hand-over execution to label a = Pentium USB token decrypts code and sends ready signal send parameter 41 to the token = USB token send the encrypted code of g to the USB token collect g(11) and hand-over execution to label b Rennes presentation But how secure are these cards/keys? s The following slides will explain in a hopefully entertaining way the most recent attacks and protections on cards. Keywords: beef, hotel, pot, vodka, aircraft, saturn, jupiter, cryptography, telescope, journalist, Fredholm... 14 Rennes presentation SIDE CHANNEL ATTACKS Measure the circuit's processing time and current consumption to infer what is going on inside it. + input  15 output ¸ Rennes presentation POWER ATTACKS s Seattle, 1999. s US and French delegates negotiate under which conditions beef could be imported to France. « The Sun » sends a journalist to investigate: ? 16 Rennes presentation POWER ATTACKS s But there is a technical problem: negotiations take place in a hotel which windows are opaque 17 Rennes presentation POWER ATTACKS s Idea: look at the hotel’s electricity meter! 18 Rennes presentation POWER ATTACKS s disk is spinning slowly: DEAL CONCLUDED + 19 Rennes presentation POWER ATTACKS s But if the disk is spinning quickly: THE SUN NEGOTIATORS BREAK ! A London homeless eaten by giant rat! + Experts say : sterility is hereditary ! + 20 Rennes presentation POWER AS FUNCTION OF HAMMING WEIGHT 21 Rennes presentation The Differential Power Attack s Differential Power Attacks (DPA) are sophisticated statistical processings of the power consumption curves. s DPA are the topic of the 2-nd part of this presentation. 22 Rennes presentation YET ANOTHER ATTACK (E BIHAM) s You put $28 in one of the pots and $10 in the other: $10 $28 $28 $10 s I ask you to multiply the contents of the blue pot by 10 and the contents of the red pot by 7, add the two results and tell me if the sum is odd or even. s Is your answer enough to reveal what’s in each pot? 23 Rennes presentation TI...
View Full Document

Ask a homework question - tutors are online