Deep neural networks are becoming popular and important assets of many AI companies. However, recent studies indicate that they are also vulnerable to adversarial attacks. Adversarial attacks can be either white-box or black-box. The white-box attacks assume full knowledge of the models while the black-box ones assume none. In general, revealing more internal information can enable much more powerful and efficient attacks. However, in most real-world applications, the internal information of embedded AI devices is unavailable, i.e., they are black-box. Therefore, in this work, we propose a side-channel information based technique to reveal the internal information of black-box models. Specifically, we have made the following contributions: (1) we are the first to use side-channel information to reveal internal network architecture in embedded devices; (2) we are the first to construct models for internal parameter estimation; and (3) we validate our methods on real-world devices and applications. The experimental results show that our method can achieve 96.50 accuracy on average. Such results suggest that we should pay strong attention to the security problem of many AI applications, and further propose corresponding defensive strategies in the future.
Side-channel attack (SCA) is a very powerful tool in attacking encrypted systems. Traditionally, the encryption process is considered as a perfect black-box. However, in real-world applications, information can be leaking @cite_38 . Initially, SCA is focused on differential power analysis @cite_4 and timing attacks @cite_37 . Later, more side-channel information and attacking methods are developed. @cite_33 propose a cache based SCA to extract the private encryption keys. @cite_17 extract full 4096-bit RSA keys successfully using the computer audio information during the decryption process. By cloning the USIM cards, @cite_15 can recover the encryption key and other information contained from the 3G 4G USIM cards. Defense against SCA is also well studied @cite_8 .
@cite_38 @cite_37 @cite_4 @cite_33 @cite_8 @cite_15 @cite_17
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This paper demonstrates the improved power and electromagnetic (EM) side-channel attack (SCA) resistance of 128-bit Advanced Encryption Standard (AES) engines in 130-nm CMOS using random fast voltage dithering (RFVD) enabled by integrated voltage regulator (IVR) with the bond-wire inductors and an on-chip all-digital clock modulation (ADCM) circuit. RFVD scheme transforms the current signatures with random variations in AES input supply while adding random shifts in the clock edges in the presence of global and local supply noises. The measured power signatures at the supply node of the AES engines show upto 37 @math reduction in peak for higher order test vector leakage assessment (TVLA) metric and upto 692 @math increase in minimum traces required to disclose (MTD) the secret encryption key with correlation power analysis (CPA). Similarly, SCA on the measured EM signatures from the chip demonstrates a reduction of upto 11.3 @math in TVLA peak and upto 37 @math increase in correlation EM analysis (CEMA) MTD. Side-channel attacks are usually performed by employing the "divide-and-conquer" approach, meaning that leaking information is collected in a divide step, and later on exploited in the conquer step. The idea is to extract as much information as possible during the divide step, and to exploit the gathered information as efficiently as possible within the conquer step. Focusing on both of these steps, we discuss potential enhancements of Bernstein's cache-timing attack against the Advanced Encryption Standard (AES). Concerning the divide part, we analyze the impact of attacking different key-chunk sizes, aiming at the extraction of more information from the overall encryption time. Furthermore, we analyze the most recent improvement of time-driven cache attacks, presented by Aly and ElGayyar, according to its applicability on ARM Cortex-A platforms. For the conquer part, we employ the optimal key-enumeration algorithm as proposed by Veyrat-Charvillonaet al to significantly reduce the complexity of the exhaustive key-search phase compared to the currently employed threshold-based approach. This in turn leads to more practical attacks. Additionally, we provide extensive experimental results of the proposed enhancements on two Android-based smartphones, namely a Google Nexus S and a Samsung Galaxy SII. Side-channel attacks (SCAs), such as differential power analysis or differential electromagnetic analysis, pose a serious threat to the security of embedded systems. In the literature, few articles address the problem of securing general purpose processors (GPPs) with resourceful countermeasures. However, in many low-cost applications, where security is not critical, cryptographic algorithms are typically implemented in software. Since it has been proved that GPPs are vulnerable to SCAs, it is desirable to develop efficient mechanisms to ensure a certain level of security. In this paper, we extend side-channel countermeasures to the register transfer level description. The challenge is to create a new class of processor that executes embedded software applications, which are intrinsically protected against SCAs. For that purpose, we first investigate how to integrate into the datapath two countermeasures based on masking and hiding approaches. Through an FPGA-based processor, we then evaluate the overhead and the effectiveness of the proposed solutions against time-domain first-order attacks. We finally show that a suitable combination of countermeasures significantly increases the side-channel resistance in a cost-effective way. Side channel attacks on cryptographic systems exploit information gained from physical implementations rather than theoretical weaknesses of a scheme. In recent years, major achievements were made for the class of so called access-driven cache attacks. Such attacks exploit the leakage of the memory locations accessed by a victim process. In this paper we consider the AES block cipher and present an attack which is capable of recovering the full secret key in almost real time for AES-128, requiring only a very limited number of observed encryptions. Unlike previous attacks, we do not require any information about the plaintext (such as its distribution, etc.). Moreover, for the first time, we also show how the plaintext can be recovered without having access to the cipher text at all. It is the first working attack on AES implementations using compressed tables. There, no efficient techniques to identify the beginning of AES rounds is known, which is the fundamental assumption underlying previous attacks. We have a fully working implementation of our attack which is able to recover AES keys after observing as little as 100 encryptions. It works against the OpenS SL 0.9.8n implementation of AES on Linux systems. Our spy process does not require any special privileges beyond those of a standard Linux user. A contribution of probably independent interest is a denial of service attack on the task scheduler of current Linux systems (CFS), which allows one to observe (on average) every single memory access of a victim process.