Over the last two decades FPGAs have become central components for many advanced digital systems, e.g., video signal processing, network routers, data acquisition and military systems. In order to protect the intellectual property and to prevent fraud, e.g., by cloning a design embedded into an FPGA or manipulating its content, many current FPGAs employ a bitstream encryption feature. We develop a successful attack on the bitstream encryption engine integrated in the widespread Virtex-II Pro FPGAs from Xilinx, using side-channel analysis. After measuring the power consumption of a single power-up of the device and a modest amount of off-line computation, we are able to recover all three different keys used by its triple DES module. Our method allows extracting secret keys from any real-world device where the bitstream encryption feature of Virtex-II Pro is enabled. As a consequence, the target product can be cloned and manipulated at the will of the attacker since no side-channel protection was included into the design of the decryption module. Also, more advanced attacks such as reverse engineering or the introduction of hardware Trojans become potential threats. While performing the side-channel attack, we were able to deduce a hypothetical architecture of the hardware encryption engine. To our knowledge, this is the first attack against the bitstream encryption of a commercial FPGA reported in the open literature.

Last year we were able to break KeeLoq, which is a 64 bit block cipher that is popular for remote keyless entry (RKE) systems. KeeLoq RKEs are widely used for access control purposes such as garage openers or car door systems. Even though the attack seems almost straightforward in hindsight, there where many practical and theoretical problems to overcome. In this talk I want to describe the evolution of the attack over about two years. Also, some possible future improvements using fault-injection will be mentioned. During the first phase of breaking KeeLoq, a surprisingly long time was spent on analyzing the target hardware, taking measurements and wondering why we did not succeed. In the second phase, we were able to use differential power analysis attacks successfully on numerous commercially available products employing KeeLoq code hopping. Our techniques allow for efficiently revealing both the secret key of a remote transmitter and the manufacturer key stored in a receiver. As a result, a remote control can be cloned from only ten power traces, allowing for a practical key recovery in a few minutes. With similar techniques but with considerably more measurements (typically on the order of 10,000) we can extract the manufacturer key which is stored in every receiver device, e.g., a garage door opener unit. In the third phase, and most recent phase, we were able to come up with several improvements. Most notably, we found that an SPA (simple power analysis) attack allows to recover the manufacturer key with one measurement. In the talk, we will also speculate about extensions to fault-injection and timing attacks. It is important to note that most of our findings are not specific to KeeLoq but are - in principle - applicable to any symmetric cipher with an implementation that is not sidechannel resistant.

Cryptanalysis of ciphers usually involves massive computations. The security parameters of cryptographic algorithms are commonly chosen so that attacks are infeasible with available computing resources. This contribution presents a variety of cryptanalytical applications utilizing the COPACOBANA (Cost-Optimized Parallel Code Breaker) machine which is a high-performance, low-cost cluster consisting of 120 Field Programmable Gate Arrays (FPGA). COPACOBANA appears to be the only such reconfigurable parallel FPGA machine optimized for code breaking tasks reported in the open literature. Depending on the actual algorithm, the parallel hardware architecture can outperform conventional computers by several orders of magnitude. In this work, we will focus on novel implementations of cryptanalytical algorithms, utilizing the impressive computational power of COPACOBANA. We describe various exhaustive key search attacks on symmetric ciphers and demonstrate an attack on a security mechanism employed in the electronic passport. Furthermore, we describe time-memory tradeoff techniques which can, e.g., be used for attacking the popular A5/1 algorithm used in GSM voice encryption. In addition, we introduce efficient implementations of more complex cryptanalysis on asymmetric cryptosystems, e.g., Elliptic Curve Cryptosystems (ECC) and number co-factorization for RSA.