Protecting source code against reverse engineering and theft is an important problem. The goal is to carry out computations using confidential algorithms on an untrusted party while ensuring confidentiality of algorithms. This problem has been addressed for Boolean circuits known as circuit privacy'. Circuits corresponding to real-world programs are impractical. Well-known obfuscation techniques are highly practicable, but provide only limited security, e.g., no piracy protection. In this work, we modify source code yielding programs with adjustable performance and security guarantees ranging from indistinguishability obfuscators to (non-secure) ordinary obfuscation. The idea is to artificially generate misleading' statements. Their results are combined with the outcome of a confidential statement using encrypted . Thus, an attacker must guess' the encrypted selector variables to disguise the confidential source code. We evaluated our method using more than ten programmers as well as pattern mining across open source code repositories to gain insights of (micro-)coding patterns that are relevant for generating misleading statements. The evaluation reveals that our approach is effective in that it successfully preserves source code confidentiality.
Keeping the circuit private while changing any wire value in the circuit has also been investigated @cite_11 . An attack can be detected and data can then be erased.
@cite_11
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Motivated by the problem of protecting cryptographic hardware, we continue the investigation of private circuits initiated in [16]. In this work, our aim is to construct circuits that should protect the secrecy of their internal state against an adversary who may modify the values of an unbounded number of wires, anywhere in the circuit. In contrast, all previous works on protecting cryptographic hardware relied on an assumption that some portion of the circuit must remain completely free from tampering. We obtain the first feasibility results for such private circuits. Our main result is an efficient transformation of a circuit C, realizing an arbitrary (reactive) functionality, into a private circuit C′ realizing the same functionality. The transformed circuit can successfully detect any serious tampering and erase all data in the memory. In terms of the information available to the adversary, even in the presence of an unbounded number of adaptive wire faults, the circuit C′ emulates a black-box access to C. Trust in reference to integrated circuits addresses the concern that the design and or fabrication of the integrated circuit (IC) may be purposely altered by an adversary. The insertion of a hardware Trojan involves a deliberate and malicious change to an IC that adds or removes functionality or reduces its reliability. Trojans are designed to disable and or destroy the IC at some future time or they may serve to leak confidential information covertly to the adversary. Trojans can be cleverly hidden by the adversary to make it extremely difficult for chip validation processes, such as manufacturing test, to accidentally discover them. This paper investigates the sensitivity of a power supply transient signal analysis method for detecting Trojans. In particular, we focus on determining the smallest detectable Trojan, i.e., the least number of gates a Trojan may have and still be detected, using a set of process simulation models that characterize a TSMC 0.18 μm process. We also evaluate the sensitivity of our Trojan detection method in the presence of measurement noise and background switching activity. A successful detection of the stealthy dopant-level circuit trojan, proposed by at CHES 2013 [1], is reported. Contrary to an assumption made by , dopant types in active region are visible with either scanning electron microscopy SEM or focused ion beam FIB imaging. The successful measurement is explained by an LSI failure analysis technique called the passive voltage contrast [2]. The experiments are conducted by measuring a dedicated chip. The chip uses the diffusion programmable device [3]: an anti-reverse-engineering technique by the same principle as the stealthy dopant-level trojan. The chip is delayered down to the contact layer, and images are taken with 1 an optical microscope, 2 SEM, and 3 FIB. As a result, the four possible dopant-well combinations, namely i p+ n-well, ii p+ p-well, iii n+ n-well and iv n+ p-well are distinguishable in the SEM images. Partial but sufficient detection is also achieved with FIB. Although the stealthy dopant-level circuits are visible, however, they potentially make a detection harder. That is because the contact layer should be measured. We show that imaging the contact layer is at most 16-times expensive than that of a met al layer in terms of the number of images. Malicious tampering of the internal circuits of ICs can lead to detrimental results. Insertion of Trojan circuits may change system behavior, cause chip failure or send information to a third party. This paper presents an information-theoretic approach for Trojan detection. It estimates the statistical correlation between the signals in a design, and explores how this estimation can be used in a clustering algorithm to detect the Trojan logic. Compared with the other algorithms, our tool does not require extensive logic analysis. We neither need the circuit to be brought to the triggering state, nor the effect of the Trojan payload to be propagated and observed at the output. Instead we leverage already available simulation data in this information-theoretic approach. We conducted experiments on the TrustHub benchmarks to validate the practical efficacy of this approach. The results show that our tool can detect Trojan logic with up to 100 coverage with low false positive rates. One aspect of security in mobile code is privacy: private (or secret) data should not be leaked to unauthorised agents. Most of the work on secure information flow has until recently only been concerned with detecting direct and indirect flows. Secret information can however be leaked to the attacker also through covert channels. It is very reasonable to assume that the attacker, even as an external observer, can monitor the timing (including termination) behaviour of the program. Thus to claim a program secure, the security analysis must take also these into account. In this work we present a surprisingly simple solution to the problem of detecting timing leakages to external observers. Our system consists of a type system in which well-typed programs do not leak secret information directly, indirectly or through timing, and a transformation for removing timing leakages. For any program that is well typed according to Volpano and Smith [VS97a], our transformation generates a program that is also free of timing leaks. 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. Privacy amplification allows two parties Alice and Bob knowing a partially secret string S to extract, by communication over a public channel, a shorter, highly secret string S'. Bennett, Brassard, Crepeau, and Maurer showed that the length of S' can be almost equal to the conditional Renyi entropy of S given an opponent Eve's knowledge. All previous results on privacy amplification assumed that Eve has access to the public channel but is passive or, equivalently, that messages inserted by Eve can be detected by Alice and Bob. In this paper we consider privacy amplification secure even against active opponents. First it is analyzed under what conditions information-theoretically secure authentication is possible even though the common key is only partially secret. This result is used to prove that privacy amplification can be secure against an active opponent and that the size of S' can be almost equal to Eve's min-entropy about S minus 2n 3 if 5 is an n-bit string. Moreover, it is shown that for sufficiently large n privacy amplification is possible when Eve's min-entropy about S exceeds only n 2 rather than 2n 3. Many semiconductor chips used in a wide range of applications require protection against physical attacks or tamper resistance. These attacks assume that a direct access to the chip is possible with either establishing electrical connections to signal wires or at least doing some measurements. The importance of protection against physical attacks is dictated by the amount of valuable and sensitive information stored on the chip. This could be secret data or company secrets and intellectual property (IP), electronic money for service access, or banking smartcards. The security in chips serves to deter prospective attackers from performing unauthorized access and benefiting from it. There are many areas that rely on tamper resistance of silicon chips. One of the first was car industry with theft protection and car alarms. Then in the early 1990s service providers such as PayTV, satellite TV, and utility companies realized that their service can be stolen if the access and payment cards are not properly protected. From the late 1990s home entertainment companies realized that their game consoles became the target of dishonest users who wanted to run illegal copies of the games. These days many device manufacturers from computer peripherals and mobile phones to printers and computers are worried about possible IP theft by third parties – either competitors or subcontractors. All the above challenges force hardware engineers to find secure solutions – either better protected off-the-shelf chips or their own custom chips. As in most cases it is impractical to block direct access to the device and its components, protection against physical attacks became the essential part of the system design. These days we have a continuous battle between the manufacturers who invent new security solutions learning their lessons from previous mistakes and the hacker community which is constantly trying to break the protection in various devices. Both sides are also constantly improving their knowledge and experience. In this endless war, the front line shifts forward and backward regularly. Deep down, the problem concerns both economics and law. On the one hand, when dishonest people try to steal property, there will be a demand to increase security. On the other, reverse engineering was always part of technological progress, helping to design compatible products and improve existing ones. The dividing line between legal (reverse engineering) and illegal (piracy) is difficult. Non-volatile memory devices such as phase change memories and memristors are promising alternatives to SRAM and DRAM main memories as they provide higher density and improved energy efficiency. However, non-volatile main memories (NVMM) introduce security vulnerabilities. Sensitive data such as passwords and keys residing in the NVMM will persist and can be probed after power down. We propose sneak-path encryption (SPE), for memristor-based NVMM. SPE exploits the physical parameters, multilevel cell (MLC) capability and the sneak paths in crossbar memories to encrypt the data stored in memristor-based NVMM. We investigate three attacks on NVMMs and show the resilience of SPE against them. We use a cycle accurate simulator to evaluate the security and performance impact of SPE based NVMM. SPE can secure the NVMM with a latency of 16 cycles and 1.5 performance overhead. This paper studies the secrecy capacity of unicast communication in a wireless erasure network setting in the presence of a wire-tapper. From an information-theoretic setting of perfect secrecy, both upper bounds and achievable secrecy rates are presented. Secrecy capacity is determined in closed form for a class of broadcast constrained erasure networks. We propose a method that provides information-theoretic security for client-server communications. By introducing an appropriate encoding scheme, we show how a client-server architecture under active attacks can be modeled as a binary-erasure wiretap channel. The secrecy capacity of the equivalent wiretap channel is then used as a metric to optimize the architecture and limit the impact of the attacks. Upper and lower bounds of the optimal secrecy capacity are derived and analyzed. While still mostly of theoretical interest, our analysis sheds some light on the practical design of resistant and secure client-server architectures. In a block-chain IoT environment, when data or device authentication information is put on a block chain, personal information may be leaked through the proof-of-work process or address search. In this paper, we apply Zero-Knowledge proof to a smart meter system to prove that a prover without disclosing information such as public key, and we have studied how to enhance anonymity of block chain for privacy protection. A novel power attack resistant cryptosystem is presented in this paper. Security in digital computing and communication is becoming increasingly important. Design techniques that can protect cryptosystems from leaking information have been studied by several groups. Power attacks, which infer program behavior from observing power supply current into a processor core, are important forms of attacks. Various methods have been proposed to countermeasure the popular and efficient power attacks. However, these methods do not adequately protect against power attacks and may introduce new vulnerabilities. In this work, we addressed a novel approach against the power attacks, i.e., Dynamic Voltage and Frequency Switching (DVFS). Three designs, naive, improved and advanced implementations, have been studied to test the efficiency of DVFS against power attacks. A final advanced realization of our novel cryptosystem was given out, which achieved enough high power trace entropy and time trace entropy to block all kinds of power attacks, with 27 energy reduction and 16 time overhead for DES encryption and decryption algorithms. IEEE 802.11 wireless networks are plagued with problems of unauthorized access. Left undetected, unauthorized access is the precursor to additional mischief. Current approaches to detecting intruders are invasive or can be evaded by stealthy attackers. We propose the use of spectral analysis to identify a type of wireless network interface card. This mechanism can be applied to support the detection of unauthorized systems that use wireless network interface cards that are different from that of a legitimate system. The approach is passive and works in the presence of encrypted traffic. New attacker scenarios involving integrated circuits (ICs) are emerging that pose a tremendous threat to national security. Concerns about overseas fabrication facilities and the protection of deployed ICs have given rise to methods for IC authentication (ensuring that an IC being used in a system has not been altered, replaced, or spoofed) and hardware Trojan Horse (HTH) detection (ensuring that an IC fabricated in a nonsecure facility contains the desired functionality and nothing more), but significant additional work is required to quell these treats. This paper discusses how a technique for precisely measuring the combinational delay of an arbitrarily large number of register-to-register paths internal to the functional portion of the IC can be used to provide the desired authentication and design alteration (including HTH implantation) detection. This low-cost delay measurement technique does not affect the main IC functionality and can be performed at-speed at both test-time and run-time. We evaluate the effectiveness of secret key extraction, for private communication between two wireless devices, from the received signal strength (RSS) variations on the wireless channel between the two devices. We use real world measurements of RSS in a variety of environments and settings. Our experimental results show that (i) in certain environments, due to lack of variations in the wireless channel, the extracted bits have very low entropy making these bits unsuitable for a secret key, (ii) an adversary can cause predictable key generation in these static environments, and (iii) in dynamic scenarios where the two devices are mobile, and or where there is a significant movement in the environment, high entropy bits are obtained fairly quickly. Building on the strengths of existing secret key extraction approaches, we develop an environment adaptive secret key generation scheme that uses an adaptive lossy quantizer in conjunction with Cascade-based information reconciliation [7] and privacy amplification [14]. Our measurements show that our scheme, in comparison to the existing ones that we evaluate, performs the best in terms of generating high entropy bits at a high bit rate. The secret key bit streams generated by our scheme also pass the randomness tests of the NIST test suite [21] that we conduct. In this work, the critical role of noisy feedback in enhancing the secrecy capacity of the wiretap channel is established. Unlike previous works, where a noiseless public discussion channel is used for feedback, the feed-forward and feedback signals share the same noisy channel in the present model. Quite interestingly, this noisy feedback model is shown to be more advantageous in the current setting. More specifically, the discrete memoryless modulo-additive channel with a full-duplex destination node is considered first, and it is shown that the judicious use of feedback increases the secrecy capacity to the capacity of the source-destination channel in the absence of the wiretapper. In the achievability scheme, the feedback signal corresponds to a private key, known only to the destination. In the half-duplex scheme, a novel feedback technique that always achieves a positive perfect secrecy rate (even when the source-wiretapper channel is less noisy than the source-destination channel) is proposed. These results hinge on the modulo-additive property of the channel, which is exploited by the destination to perform encryption over the channel without revealing its key to the source. Finally, this scheme is extended to the continuous real valued modulo-Lambda channel where it is shown that the secrecy capacity with feedback is also equal to the capacity in the absence of the wiretapper. We investigate the effect of certain active attacks on the secrecy capacity of wiretap channels by considering arbitrarily varying wiretap channels. We establish a lower bound for the secrecy capacity with randomized coding of a class of such channels and an upper bound for that of all such channels. We show that if the arbitrarily varying wiretap channel possesses a bad “averaged” state, namely one in which the legitimate receiver is degraded with respect to the eavesdropper, then secure communication is not possible. We address the question whether quantum memory is more powerful than classical memory. In particular, we consider a setting where information about a random n-bit string X is stored in s classical or quantum bits, for s<n, i.e., the stored information is bound to be only partial. Later, a randomly chosen predicate F about X has to be guessed using only the stored information. The maximum probability of correctly guessing F(X) is then compared for the cases where the storage device is classical or quantum mechanical, respectively. We show that, despite the fact that the measurement of quantum bits can depend arbitrarily on the predicate F, the quantum advantage is negligible already for small values of the difference n-s. Our setting generalizes the setting of who considered the problem of guessing an arbitrary bit (i.e., one of the n bits) of X. An implication for cryptography is that privacy amplification by universal hashing remains essentially equally secure when the adversary's memory is allowed to be quantum rather than only classical. Since privacy amplification is a main ingredient of many quantum key distribution (QKD) protocols, our result can be used to prove the security of QKD in a generic way. Erasure codes, such as Reed-Solomon (RS) codes, are increasingly being deployed as an alternative to data-replication for fault tolerance in distributed storage systems. While RS codes provide significant savings in storage space, they can impose a huge burden on the I O and network resources when reconstructing failed or otherwise unavailable data. A recent class of erasure codes, called minimum-storage-regeneration (MSR) codes, has emerged as a superior alternative to the popular RS codes, in that it minimizes network transfers during reconstruction while also being optimal with respect to storage and reliability. However, existing practical MSR codes do not address the increasingly important problem of I O overhead incurred during reconstructions, and are, in general, inferior to RS codes in this regard. In this paper, we design erasure codes that are simultaneously optimal in terms of I O, storage, and network bandwidth. Our design builds on top of a class of powerful practical codes, called the product-matrix-MSR codes. Evaluations show that our proposed design results in a significant reduction the number of I Os consumed during reconstructions (a 5× reduction for typical parameters), while retaining optimality with respect to storage, reliability, and network bandwidth.