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With the popularization of IoT devices, more and more valuable data is generated.Analyzing and mining big data based on IoT devices has become a hot topic in the academic and industrial circles in recent years.However, due to the lack of necessary detection and protection methods, many IoT devices have serious information security risks.In particular, device hard-coded information is closely related to system encryption and decryption, identity authentication and other functions, which can provide confidentiality protection for core data.Once this information is exploited by malicious attackers, serious consequences such as sensitive information leakage, backdoor attacks, and unauthorized logins will occur.In response to this problem, a multi-type character recognition and positioning scheme was designed and a hard-coded vulnerability detection method in executable files was proposed based on the study of the characteristics of hard-coded vulnerabilities in IoT devices.The proposed method extracted the firmware of IoT devices and filtered all executable files as the source to be analyzed.Then, a solution to identify and locate three types of hard-coded characters was provided.Further, the reachability of the function, where the hard-coded character was located, was analyzed according to the function call relationship.Meanwhile, the instruction heterogeneity was mitigated by an intermediate representation (IR) model.The character and parameter hard-coded values was obtained through a data flow analysis approach.A symbolic execution method was devised to determine the trigger conditions of the hard-coded vulnerabilities, and then the vulnerability detection result was output.On the one hand, the proposed method introduced the method of symbolic execution based on the use of the intermediate representation model, which eliminated the dependency of instruction architecture and reduces the false positive rate of vulnerabilities; On the other hand, this method can integrate characters, files, and cryptographic implementation to realize the different characteristics of three types of hard-coded characters, which increased the coverage of vulnerability detection and improves the versatility of the detection method.The experimental results show that the proposed method can effectively detect three types of hard-coded vulnerabilities of characters, files and cryptographic implementation in various IoT devices, and has good detection accuracy, which can provide certain guidance for the deployment of subsequent security protection technologies.

Although dearomative functionalizations enable the direct conversion of flat aromatics into precious three‐dimensional architectures, the case for simple arenes remains largely underdeveloped owing to the high aromatic stabilization energy. We herein report a dearomative sequential addition of two nucleophiles to arene π‐bonds through umpolung of chromium–arene complexes. This mode enables divergent dearomative carbonylation reactions of benzene derivatives by tolerating various nucleophiles in combination with alcohols or amines under CO‐gas‐free conditions, thus providing modular access to functionalized esters or amides. The tunable synthesis of 1,3‐ or 1,4‐cyclohexadienes as well as the construction of carbon quaternary centers further highlight the versatility of this dearomatization. Diverse late‐stage modifications and derivatizations towards synthetically challenging and bioactive molecules reveal the synthetic utility. A possible mechanism was proposed based on control experiments and intermediate tracking. [ABSTRACT FROM AUTHOR]

It is of great significance to characterize the dynamics of underwater explosive bubbles in close proximity to mutually perpendicular walls for ensuring the safety of important underwater structures. In this paper, a dynamic experiment on underwater explosion bubbles was carried out near constructed mutually perpendicular walls. High-speed cameras were utilized to capture high-resolution images, while pressure sensors recorded pressure–time history curves. The main focus was on studying the evolution process of bubble morphology and pulse characteristics. When the position of the charge's center relative to the horizontal wall remained fixed, decreasing the distance between the charge's center and the vertical wall resulted in a reduction in the equivalent maximum radius of bubbles and an increase in its pulsation period. Additionally, the asymmetric collapse of bubbles on a single wall transformed into asynchronous collapse on two walls, with most collapsed bubbles tending to migrate and expand toward the corner formed by mutually perpendicular walls. The resulting jet from the collapse of bubbles exhibited deflection toward the vertical wall, with an inclination angle increasing approximately proportionally with dimensionless distance ratio γ h / γ v . Moreover, it became more difficult for achieving effective focusing of bubble energy as the jet approached the corners formed by mutually perpendicular walls. The experiments also implied that reducing the dead weight of the vertical wall weakened its contact with the horizontal wall, causing an increase in the equivalent maximum radius of bubbles and jet inclination, as well as a decrease in the bubble pulsation period, under the same dimensionless distance γ v . [ABSTRACT FROM AUTHOR]