Breaking AES (Manual CPA Attack)

January 18, 2018 Written by Thomas Carstensen
The Tutorial B5 has shown how you can break AES on a relative “easy” way. We have learned much new theoretic information for that method. But the Tutorial was limited on the Attack himself as well as the background and explanations how the Attack works. But the evaluation of the traces and the meaningful gradation on the display was realized by the software itself. But in our own Test on real Hardware we may not use that software so easily. Because of that the Tutorial B6 shows how to evaluate the Traces manually. It explains all necessary steps for interpreting…

Breaking DES (Straightforward)

January 18, 2018 Written by Thomas Carstensen
After breaking AES, in this Tutorial we would break its precursor: DES (Data Encryption Standard). It was redeemed on October 2000 by AES. In this example the key length are 8 Byte which equates 64 bit. It must be pointed out, that the algorithm only consider the First-Round-Key. That means 48 relevant bits (8 S-Boxes x 6 Bits) but the original Key has 56 significant bits. The remaining bits to 64 can be neglect because there are just parity bits. If the 48 bits were found by the CPA there are just 8 bits left which are important for the…

Breaking AES (Straightforward)

January 17, 2018 Written by Thomas Carstensen
The B4 tutorial is not available and will be released for the next version of the ChipWhisperer API. Tutorial B5 is about a software implementation of AES which was written in C. It´s possible to do this tutorial on 4 different boards. We used the XMEGA board. First we connected the ChipWhisperer-Lite to the XMEGA Target-Board as usual and connected the ChipWhisperer-Lite to our notebook. Then we compiled the simpleserial-aes.hex and programmed it to the XMEGA. Before we could capture the first traces, we had to reopen the software to exclude problems with the connection. At the Interface we changed…
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