Analysis Method Research On The Block Cipher AES

The urgency of the information system security and the importance network communicati-ons of safety make people are increasingly interested in theories of block cipher, block cipheranalysis and design also has been a hot topic in cryptography. Block cipher is an importantresearch branch of modern cryptography, its birth and development has a wide range of practicalbackground and important theoretical value.The USA National Institute of Standard and Technology Institute after a series of evaluation,selected Rijndael algorithm from a large number of block cipher , announced that the algorithmas the AES algorithm[1,2,3,4]in November 26, 2001. The AES algorithm as USA data encryptionstandard algorithm, represent the highest level of international cryptography sector in the field ofblock cipher design and attack. Thus safety analysis is a challenging task, and have a majorcryptography significance. Around the safety analysis of the AES algorithm, some achievementshave been obtained in this paper:The meet-in-the-middle attack methods successful analysis the AES algorithm predecessorSquare algorithm. First, we constructed a fourth round differentiator, then used the differentiatorto analyze the relations between bytes,used the idea of meet-in-the-middle attack,encryption fiveround，compare the values obtained by this decryption to the values in the precomputed set, thenverify that whether the guessed key correct or not;Induce a fault at the input of the last fourth round, attack complete AES-128. Induce a faultdifferential bytes in the input of the seventh round, then by four round operations to get the faultciphertext,composed of four equations by the proportional relationship between the differencevalue four equations proportional relationship guess keys, theoretically only required two pairsof plaintext and cipher to recovery the right key .