A Hardware Security Protection Method for Conditional Branches of Embedded Systems.

The branch prediction units (BPUs) generally have security vulnerabilities, which can be used by attackers to tamper with the branches, and the existing protection methods cannot defend against these attacks. Therefore, this article proposes a hardware security protection method for conditional branches of embedded systems. This method calculates the number of branch target buffer (BTB) updates every 80 clock cycles. If the number exceeds the set threshold, the BTB will be locked and prevent any process from tampering with the BTB entries, thereby resisting branch prediction analysis (BPA) attacks. Moreover, to prevent attackers from stealing the critical information of branches, the method designs the hybrid arbiter physical unclonable function (APUF) circuit to encrypt and decrypt the directions, addresses, and indexes of branches. This circuit combines the advantages of double APUF and Feed-Forward APUF, which can enhance the randomness of output response and resist machine learning attacks. If attackers still successfully tamper with the branches and disrupt the control flow integrity (CFI), this method detects tampering with the instruction codes, jump addresses, and jump directions in a timely manner through dynamic and static label comparison. The proposed method is implemented and tested on FPGA. The experimental results show that this method can achieve fine-grained security protection for conditional branches, with about 5.4% resource overhead and less than 5.5% performance overhead.

Treatment with sivelestat sodium of acute respiratory distress syndrome induced by chemical pneumonitis: A report of three cases.

Inhalation of acid fumes and aspiration of liquid substances or gastric contents may not initiate dyspnea within several hours after exposure but may result in delayed onset of alveolar edema. The present report presents three cases of inhalation or aspiration of chemical substances that resulted in acute respiratory distress syndrome (ARDS). Due to different underlying reasons, three patients developed ARDS resulting from chemical pneumonitis and pulmonary infection. From patients with dyspnea, dry rales could be heard in both lungs, with <92% percutaneous oxygen saturation at room air. All patients were treated using a high-flow nasal cannula and sivelestat sodium. Oxygenation gradually improved and the patients were discharged without adverse events. These cases suggest that early treatment with sivelestat sodium may improve the clinical outcomes of patients with ARDS.