The Design And Implementation Of SQLite Data Recovery System

The SQLite database used by mobile APP contains a lot of private information,which often plays a vital role in criminal investigation and electronic forensics.In this paper,aiming at the problem of recover data in smart phone APP,a method that orientes to SQLite database is implemented.Moreover,this method combines logic processing interface and physical data structure analysis to recover data.Compared with traditional recovery methods,it can improve the deletion recovery rate and enhance compatibility.The research of this topic includes the following contents:(1)Design and implement the data preprocessing module.This module is mainly responsible for loading DB files and extracting table header information.Meanwhile,it calls the SQLite interface to get table structure information.The module also uses the traditional logic recovery algorithm and temporarily stores the initial recovery results.This module preprocesses the input data and provides necessary information for the next recovery process.(2)Design and implement the data structure traversal module.This module traverses the data storage structure of SQLite file and finds the location of each valid node,including the specific offset address of free block and free leaf,which can help to accurately get the starting position of the information to be recovered.(3)Design and implement the data matching module.The core of this module uses a method with similar type matching algorithm,and makes corresponding adaptations according to the actual scene to effectively match the data to be recovered.Compared with the traditional method,it is more accurate and can be applied in more scenarios.Moreover,the total data recovery rate is improved obviously.(4)Design and implement the data recovery module.The module recover data in two data formats: free block and free page.By parsing different storage scenarios,corresponding algorithms are applied and data matching module is called to recover data records one by one.Then the recovered data are processed including the removing redundant data,the filtering of scrambled data and the merging of continuous incomplete data.Finally,according to the project plan,combined with the system function and the test data from mobile application,I designed and implemented the feasibility verification and system testing.The results showed that this method toke better effect on most actual usage scenarios for data recovery,higher deletion recovery rate and less dependence on external environment than other methods.