uBlock and RAIN are both SPN structure lightweight block ciphers with sufficient security against traditional attacks. This article mainly focuses on the zero-correlation linear cryptanalysis of uBlock-128/128 and RAIN-64 without considering the whitening key for the first time. On the one hand, combining the linear mask propagation rules of S-box with matrix method, a large number of 4-round zero-correlation linear approximations for uBlock-128/128 are obtained. Therefore, a 6-round key recovery attack is carried out with partial-compression technique, which can recover 48-bit subkeys with data complexity 2 126.41 known plaintexts, time complexity 2 122.82 times of 6-round of algorithm encryptions, and memory complexity 2 48 nibbles. On the other hand, a similar method is used on RAIN-64, thus a 10-round attack is performed, which recovers 64-bit subkeys with data complexity 2 61.95 known plaintexts, time complexity 2 74.26 times of 10-round algorithm encryptions, and memory complexity 2 64 nibbles. The results show that both uBlock and RAIN are safe enough to resist zero-correlation linear cryptanalysis.

We present an overview of instructions for the use of European historical cipher keys in early modern times. We describe the structure of instructions and the content presented to the key users. We exemplify various key instruction types and give a text edition of typical examples in various languages. The study is based on the analysis of more than 1,600 cipher keys collected from archives and libraries in ten European countries. We examine the practical implementation of cipher keys to the extent that instructions offer insights into everyday cryptographic practices. We focus on the typical rules scribes were expected to adhere to and the common errors they were instructed to avoid. We aim to reconstruct the apprehensions and considerations of the authors of cipher keys: They sought to offer assistance to users while likely harboring concerns regarding the potential misuse of their intellectual product. Given the secretive nature of cryptology, the documentation of knowledge transfer is scarce. In addition to the detailed manuals authored by well-known cryptologists, anonymous cipher key instructions offer valuable insights into this knowledge transfer process. By studying these instructions, historians gain direct access to a realm of knowledge that would otherwise remain hidden from their view.

This article presents a cryptanalysis of a 19th-century encrypted manuscript discovered in the archives of Conde de Siete Fuentes in Tenerife, Canary Islands, Spain. The manuscript, preserved by the heirs of the 6th Count of Valle de Salazar, utilizes a polyalphabetic substitution cipher. The cryptanalysis was performed by applying statistical frequency analysis and developing a Python script for decryption, resulting in the authors successfully deciphering the message. The decrypted letter reveals political communications discussing the strategic positioning of Tenerife as the capital, the dissolution of local councils, and the influence of key political figures. The analysis compares the cipher with historical encryption techniques, and identifies the unique characteristics of the manuscript’s encryption method. The study highlights the political dynamics and alliances within Tenerife’s nobility and their interactions with the central Spanish government, providing significant insights into, both, the cryptographic practices and political maneuvers of the time.

Abraham Adrian Albert “A cubed” (1905–1972) was an algebraist best known academically for his study of associative and non-associative algebras. By the 1940s he had also developed an interest in cryptology and its relationship to mathematics. Throughout the following two decades, Albert would participate in several mathematics programs to study and advise on cryptanalysis. In particular, Albert’s work with the National Security Agency (NSA) set a framework for the development of cryptology as a mathematical discipline. This research aims to present a timeline for and the breadth of Albert’s promotion of cryptology in the post-WWII American mathematical community and to examine, for the first time, reports Albert authored under contract with the NSA. In doing so, we hope to better understand the relationship between the NSA and academic mathematicians at the time of writing. The reports, released in 2020 by the NSA in response to a 2010 Freedom of Information Act request, have been arranged by the author into eleven collections based on content. Each collection will be introduced with their ideas and results given in a roughly chronological order. These collections span ideas in group theory, field theory, matrix algebra, and geometry, most often with application to cryptological systems.

Condenser PBJ is a mechanical cipher machine developed by Pavel Baráček-Jacquier (1885-1969). It was created between 1922 and 1924, and was used by the Czechoslovak diplomatic service until 1934. The machine was designed to be used as a tool for condensing telegraphic messages in a similar way to a codebook, but with encryption added to the result. The encryption algorithm is a polyalphabetic substitution cipher—an autokey cipher with a priming key of length 10. This autokey cipher is different however from the classical Vigenère autokey cipher. We have been able to fully reconstruct the encryption algorithm. We also present a detailed description of the machine, and point out some weaknesses in the cipher’s design.

The most widely used technology at the moment is the Internet of Things (IoT), which is expanding at a rapid pace because it allows us to remotely control and manage a variety of smart devices and relieves us from our demanding daily routines. Technology is also vulnerable to security breaches, as evidenced by the rise in cybercrimes and identity theft. More so than any other known IoT security breach, side-channel analysis is extremely insecure. A current issue for lightweight IoT applications is differential power analysis, a kind of side-channel analysis that is very accurate in obtaining the secret key. As a result, developing a safe style takes more time and effort. PRESENT is an easy-to-use, low-power encryption algorithm that is based on Advanced Encryption Standard (AES) and is utilized in IoT devices like RFID tags and access cards. Even with the plethora of countermeasures proposed in the last ten years, none are able to keep up with the IoT’s rapid expansion. A clever combination of masking and hiding techniques could stop several security breaches. Masked three-phase dual rail pre-charge logic is a new hybrid countermeasure that thwarts combined side-channel attacks and is suggested as a means of attaining the necessary degree of security. The hybrid design utilized in PRESENT resulted in an increase in complexity and required more work in terms of area and power. Consequently, more PRESENT optimization techniques are applied. Additionally, for PRESENT hardware implementation, a flexible key scheduling structure with parallel input and output is proposed. Using the Cadence Virtuoso simulation tool with 180-nm technology, a secured structure combining optimized algorithm and secured logic is designed, and the outcomes are analyzed. Normalized energy deviation (NED)/normalized standard deviation (NSD) analysis and Pearson correlation are used to analyze safety. The simulation results for the gates show that our proposed logic has the lowest values of NED and NSD at the assigned frequencies. When compared with side-channel analysis, the outcomes have shown to be both safe and effective. In comparison to earlier designs, the suggested system’s area and power consumption are cut by 67% and 64%, respectively.