7-Zip加密文件快速口令恢复算法研究OA

With the widespread use of 7-Zip software,the rapid recovery of 7-Zip encrypted file pass-words is of practical significance for electronic forensics in information security.At present,the pass-word recovery of 7-Zip encrypted files mainly depends on 219 rounds of SHA256 to generate AES256 keys combined with CRC verification code,which is inefficient.This paper proposes a fast password recovery algorithm using plaintext characteristics for verification by studying the plaintext statistical characteristics of 7-Zip encrypted files.By analyzing the vulnerability of 7-Zip encryption process,a fast password recovery algorithm using key table for decryption is proposed.The experimental data shows that the algorithm designed in this paper greatly reduces the amount of computation.Compared with the most widely used John cracking software in the industry,its password cracking speed can be improved thousands of times.