Algebraic Attack on 2-Round SMALLPRESENT-[2] Algorithm
Tsamara Khadijah Silim, Muhammad Faturrohman Sugiyarto, Nadia Paramita Retno Adiati, Santi Indarjani · 2023
Block cipher is a symmetric key algorithm by mapping plaintext blocks into ciphertext blocks. Block ciphers can be classified into several of structures, such as Feistel and SPN. The SMALLPRESENT-[2] algorithm is a simplified version of the PRESENT-80 algorithm using 8 bits of key and 8 bits of message input with SPN structure. In this paper, the algebraic attack is performed on the 2-round SMALLPRESENT-[2]. The attack is conducted to determine the algebraic representation of the algorithm in 8 multivariate polynomial equations. The algebraic representation of the algorithm is obtained from the s-Box used in the SMALLPRESENT-[2] algorithm. The equations are devided by implementing the encryption process using a randomly chosen plaintext under unknown key. The results showed that the higher order of the multivariate polynomial is 9 with 24 unknown variables to be solved. Due to the large number of unknown variables, the key recovery can be conducted using XL algorithm or Grobner Basis.