臺灣博碩士論文加值系統

病毒問題在最近幾年逐漸為人們所重視，而病毒對個人電腦使用者所造成
的損害也愈來愈嚴重。本篇論文是在假設病毒可能已侵入系統的前提下，
提出一個方法來增強系統中檔案的自我免疫能力，使得病毒無法去寄生，
防止病毒再進一步擴散，繼續感染其它檔案。此種免疫能力是根據檔案的
結構特性來產生，並非傳統注射疫苗方式。由於不是根據每種病毒特性來
設計，故與已知型或未知型病毒無關。平常放在Disk中的執行檔，因檔
案 FDB (File Descripton Block)的第一個 cluster 鏈結 (link) 和檔
案大小是被隱藏起來的,所以病毒無法感染這些檔案，只有在執行檔執行
時， "Sentinel" 才經由解碼，解開被隱藏起來的鏈結與檔案大小，且執
行檔執行時會自動再把這個在 Disk 上已解開的鏈結與檔案大小再次隱藏
起來，使病毒無法感染。

Due to the serious damage caused by viruses, people have paid
more attention to prevent files from infection. In this paper,
we propose a new algorithm which is based on file structure to
protect files from being infected by parasitic viruses. The
link between an execution file's FDB (File Description Block)
cluster following it is hided when it is not executed. Only at
the time of execution, sentinel decodes the hided link and adds
an R-Segment to the end of the execution file."Sentinel" then
call interrupt 21 which loads the execution file with the R-
Segment into the main memory. The R-Segment is executed before
the original execution file and the link is hided again by
the R-Segment. In this way, viruses cannot find execution
files and cannot infect them.