The increasing prominence of the Internet of Things (IoT) necessitates a thorough examination of IoT nodes, as they play a critical role in transmitting, processing, and storing private data. To address the security concerns associated with IoT nodes, researchers have proposed various methods for safeguarding sensitive information and ensuring secure communication. However, existing privacy protection approaches may not cater specifically to the IoT perception layer, rendering IoT devices vulnerable to security attacks. In response to this challenge, lightweight block ciphers, such as Shadow, have emerged as a potential solution. Shadow employs a novel combination technique of generalized Feistel structure and AND-RX operations, offering improved diffusion, stability, and resistance against attacks. In this article, we leverage integral cryptanalysis, particularly the mixed integral linear programming-aided method introduced by Xiang et al., to propose a 10-round integral distinguisher for Shadow-32. By extending this characteristic to 11 rounds with a novel approach, we propose the best integral distinguisher to date, featuring 16 balanced bits. In addition, we present a comprehensive integral attack on 14 rounds of Shadow-32, which exhibits a data complexity of 231, a time complexity of 256.429, and a memory complexity of 224 bytes. Although our proposed attack only targets 14 out of the 16 rounds of Shadow-32, it raises concerns about the practical security of the full-round Shadow-32. Consequently, further analysis is essential to ensure the security of IoT nodes, given their significance.

In this paper, we present a framework for biclique cryptanalysis of block ciphers which extremely requires a low amount of data. To that end, we enjoy a new representation of biclique attack based on a new concept of cutset that describes our attack more clearly. Then, an algorithm for choosing two differential characteristics is presented to simultaneously minimize the data complexity and control the computational complexity. Then, we characterize those block ciphers that are vulnerable to this technique and among them, we apply this attack on lightweight block ciphers Piccolo-80, Piccolo-128, and HIGHT. The data complexity of these attacks is only 16-plaintext-ciphertext pairs, which is considerably less than the existing cryptanalytic results. In all the attacks, the computational complexity remains the same as the previous ones or even it is slightly improved.