| Today,when information technology has penetrated into every corner of human society,people’s daily life cannot be separated from the network.While the network provides convenience to the society,it also brings information security problems.Password recovery technology and password encryption research complement each other,and are an important part of the security department’s investigation and evidence collection,intelligence acquisition and maintenance of network information security.With the proliferation of mobile Internet users,the password space has grown exponentially.Therefore,generating an efficient password dictionary becomes the key to password recovery.Aiming at the problems of large search space,poor password diversity and low password recovery hit rate in password dictionary generation,this paper proposes a password recovery method based on personal information.It mainly analyzes the password structure containing personal information and hot words in the password,generates a password dictionary according to the known personal information and statistical hot word database and password rule database,designs and implements an efficient password recovery method,and uses it Applied to PDF file password recovery.The following is the main work accomplished in this paper:1.The potential rule mining analysis is carried out on the massive real passwords of 8 domestic and foreign websites selected in this paper.The Zip-f distribution of passwords is analyzed,the N-gram model is used to extract the features of passwords,the length of passwords,password types,popular passwords and keyboard rules are statistically analyzed,and the rules of real password creation are summarized from multiple perspectives.Provide regular support for generating password dictionary in the next step.2.A password dictionary generation method based on personal information is proposed.Construct a multi-pointer dictionary tree,collect hot words for password data set and password rules containing personal information,improve the discovery performance of personal information and hot words,and obtain hot word database and password rule database.According to the obtained personal information,hot thesaurus,corpus and keyboard rules,etc.,based on the password rule base,use Hash-Cat Best64 to generate a password dictionary,and select different password recovery strategies according to general and precise goals.Improve the diversity of passwords,password coverage and password hit rate.3.Efficient password recovery for PDF files based on FPGA.The encryption algorithm process and password recovery process of PDF17L3 file are introduced,and the core algorithm is pre-computed,CSA strategy,and pipeline optimization.Using the password dictionary based on personal information generated in this paper,high-speed dictionary parsing is performed through the FPGA platform,and a pan-target attack is used to perform efficient password recovery on PDF files.The experimental results show the effectiveness and efficiency of the password recovery algorithm based on personal information,which effectively improves the password recovery efficiency of PDF files. |
