Date of Award

Fall 2014

Degree Type


Degree Name

Master of Science (MS)


Computer and Information Technology

First Advisor

Eugene H. Spafford

Committee Member 1

Samuel Wagstaff

Committee Member 2

Melissa Dark


Arthur-Durett, Kristine MS, Purdue University, December 2014. The weakness of WinRAR encrypted archives to compression side-channel attacks. Major Professor: Eugene Spaff This paper explores the security of WinRAR encrypted archives. Previous works concerning potential attacks against encrypted archives are studied and evaluated for practical implementation. These attacks include passive actions examining the effects of compression ratios of archives and the fi contained, the study of temporary ar- tifacts and active man-in-the-middle attacks on communication between individuals. An extensive overview of the WinRAR software and the functions implemented within it is presented to aid in understanding the intricacies of attacks against archives. Several attacks are chosen from the literature to execute on WinRAR v5.10. Select fi types are identifi through the examination of compression ratios. The appear- ance of a fi in an archive is determined through both the appearance of substrings in the known area of an archive and the comparison of compression ratios. Finally, the author outlines a revised version of an attack that takes advantage of the independence between the compression and encryption algorithms. While a previous version of this attack only succeeded in removing the encryption from an archive, the revised version is capable of fully recovering an original document from a encrypted compressed archive. The advantages and shortcomings of these attacks are discussed and some countermeasures are briefl mentioned