A Novel Identification Approach to Encryption Mode of Block Cipher
Cheng Ling Tan, Yifu Li, Shan Yao · 2016
Encryption mode describes how a block cipher operates in a cryptosystem and the implementation detail of cryptographic algorithm.In general, the encryption mode of a block cipher is unknown to a cryptanalyst.It plays a significant role in cryptanalysis work on block cipher to identify the encryption mode.In this paper, we propose a novel identification approach to encryption mode of block cipher only with ciphertext information available.Based on the idea of SVM technology, we construct an identification system of encryption mode of block cipher.We can identify the encryption mode with a high identification rate when the key and IV of testing ciphertext files are same as those of training ciphertext files.Even if the keys or IVs of training and testing ciphertext files are different, the identification result is still superior to that of randomly guessing.Furthermore, we find that it is more difficult to identify the encryption mode of AES than DES, Blowfish, 3DES and RC5.