Design of a New Stream Cipher: PALS
This work addresses the need for secure stream ciphers, particularly in financial cryptography, but appears incremental as it builds on existing clock-controlled combination generators with memory.
The authors tackled the problem of designing a secure stream cipher by proposing PALS, a clock-controlled cipher with a new step-altering mechanism based on system theory, resulting in a keystream resistant to conventional attacks and exhibiting properties like high linear complexity and good statistical similarity to random sequences.
In this paper, a new stream cipher is designed as a clock-controlled one, but with a new mechanism of altering steps based on system theory in such a way that the structures used in it are resistant to conventional attacks. Our proposed algorithm (PALS) uses the main key with the length of 256 bits and a 32-bit message key. The most important criteria considered in designing the PALS are resistance to known attacks, maximum period, high linear complexity, and good statistical properties. As a result, the output keystream is very similar to the perfectly random sequences and resistant to conventional attacks such as correlation attacks, algebraic attack, divide & conquer attack, time-memory tradeoff attack and AIDA/cube attacks. The base structure of the PALS is a clock-controlled combination generator with memory and we obtained all the features according to design criteria with this structure. PALS can be used in many applications, especially in financial cryptography due to its proper security features