With the rapid development of industrial IoT (IIoT), a large number of embedded devices, such as sensors and tag readers, have been widely deployed for gathering and sending data. These devices are commonly unreliable and vulnerable to many threats, because they are located in unattended areas which are vulnerable to device capture attacks. Such environments can be regarded as white-box attack contexts, in which the adversary has total visibility and full control of the implementations. White-box cryptography (WBC) aims to protect implementations of symmetric encryption algorithms in white-box attack contexts. Unfortunately, existing WBC schemes are vulnerable to various attacks, and most of them are insufficiently secure in strict white-box attack contexts. Based on the investigation of existing designs and the corresponding cryptanalysis, we propose a novel design approach for securing WBC schemes, which is named state dependent selectable random substitutions (SDSRS). It uses state-dependent selectable random substitutions to defeat various related white-box cryptanalytic approaches. With special considerations for IIoT systems such as high performance for supporting real-time applications and small block size for fitting industrial protocols, a concrete WBC scheme designed with the proposed approach has been provided. Our theoretical analysis shows that the proposed scheme is secure. Additionally, experimental results indicate that the scheme performs well in practice, and it is significantly efficient in time and energy consumptions compared with existing secure white-box cryptographic schemes.

In recent years, radio frequency identification (RFID) technology has been applied in various fields to efficiently identify objects. Considering that identification is usually performed continuously, the latest RFID approaches use previous identification results for subsequent identifications and can identify two tags per unit time. However, these approaches have not utilized bit-level collision information in ID transmissions, which can facilitate the identification. Moreover, the assumption of reliable communication is not always valid in real-world applications. In this article, we propose a new approach called the multiple resolution bit tracking (MRB) to further improve the identification performance. This approach dynamically computes a tag set that can be unambiguously identified irrespective of any missing subset. These tags are requested to transmit their IDs in the same timeslot. Strategies to handle unreliable communication have also been proposed and optimized for MRB. We performed extensive simulations to validate the performance of our proposed approach. The results show that MRB can achieve 3.7 tags per unit time, which is 1.85 times the number achieved using the existing approaches. Furthermore, MRB handles unreliable communications well and achieves a small given tag missing rate.