Research On A Class Of Lightwight Cipher Algorithm

In recent years,lightweight block cipher algorithm has become a very popular research orientation in the field of cryptography.At present,due to the rapid development of Internet,lightweight block cipher is widely applied in resource-constrainedenvironments,such as wireless sensor network,smart card and wearable devices.Compared with traditional cipher algorithm,lightweight block cipher,which only needs low power consumption and a small amount of the hardware resources,is convenient and fast to achieve.In order to apply this algorithm in practical environment more efficiently,more and more professors in cipher field focus on its security.Differential fault attack,which was proposed by E.Bhiam and A.Shamir in 1997,is a new method to research the security of Data Encryption Standard(DES)algorithm.By this means,researchers only need little fault ciphertext and small search space to recover the original key of the cipher algorithm.Because of this characteristic,differential fault attack is widely used in research on security of kinds of lightweight block cipher algorithms.The author in this thesis mainly analyzes two lightweight block cipher algorithms based on SPN structure: PRESENT algorithm and KLEIN algorithm.Based on analyses about characteristics of structure and fault propagation of these algorithms,applicable models of attack are designed.And then the author uses software to build decryption process and attack process.Also,based on consequences of differential fault attack,the author analyzes the security of these algorithms by differential fault attack.Finally,to prevent the differential fault attack,an improved method of KLEIN algorithm is proposed.Specific research content are as follows:1.The structure features of PRESENT algorithm are illustrated.The author in this thesis establishes different attack models based on characteristics of fault propagation of PRESENT.And then the author uses improved ways of differential fault attack to conduct attack to this algorithm.By channeling fault into algorithm encryption process,the author attacks it in the 30 round to 3 round of this algorithm,which finally restores the original key of the algorithm.At last,the author makes some analyses on the results of attack and security of the algorithm.2.The structure features of KLEIN algorithm are illustrated.The author in this thesis establishes different attack models based on characteristics of fault propagation of KLEIN.And then the author conducts single byte differential fault attack to this algorithm.Specific attacks are made in the 10 round to 4 round of this algorithm,which finally restores all original key of the algorithm.At last,analyses on the results and security of the algorithm are discussed.3.The author in this thesis introduces the principle of the Maximal Distance Separable(MDS)matrix and proves a method to construct MDS matrix based upon exponent.Then,MDS matrix,which is generated by this means,is applied in the encryption of the KLEIN to improve its performance.At last,the author analyses the complexity and security of differential fault attack of the improved KLEIN.