Reverse Engineering

1. Reverse Engineering
Computer Science
D.I.A.T.M.

2. Introduction
To
Reverse Engineering
By, Sonal Pravin

3. CONTENTS
● What is Reverse Engineering (RE)?
● Why do we need Reverse Engineering?
● Scope and Tasks of Reverse Engineering
● Different Approaches
● RE tools
● Conclusions

4. WHAT WILL HAPPEN ?
●You have an unexpected case:
●You finished one course project using Java
●Your program runs OK
●But, by accident, you delete the java file

5. WHAT WILL HAPPEN ?
●You have an unexpected case:
●You finished one course project using Java
●Your program runs OK
●But, by accident, you delete the java file
●Solution is “Reverse Engineering”

6. WHAT IS REVERSE ENGINEERING?
●RE encompasses any activity that is done to
determine how a product works, to learn the
ideas and technology that were used in
developing that product.
●RE can be done at many levels
●RE generally belongs to Software Maintenance

7. FORWARD ENGINEERING
AND
REVERSE ENGINEERING
By, Puja kumari

8. WHAT IS FORWARD ENGINEERING ?
Waterfall Model of
software
development
Requirement
Analysis
Design
Implementation
Testing and
Maintenance

9. FORWARD ENGINEERING
Forward
Engineering
Requirements
Design
Source Code
Testing &
Maintenance

10. FORWARD ENGINEERING VS
REVERSE ENGINEERING ?
Forward Engineering Reverse Engineering
Requirements
Design
Source Code
Testing &
Maintenance

11. CONCEPT OF ABSTRACTION SYSTEM
Abstraction
System
Old system New System
Forward Engineering
Re-Implementation
Reverse Engineering
Abstraction

12. WHY DO WE NEED RE ?
●Recovery of lost information
●providing proper system documentation
●Assisting with maintenance
●identification of side effects and anomalies
●Migration to another hw/sw platform
●Facilitating software reuse

13. Benefits, Difficulties
& Scope of
Reverse Engineering
By, Ayan Pradhan

14. THE EARLY DAYS OF RE
●Law of Software Revolution (Lehman, 1980)
●Fundamental strategies for program
comprehension (Brooks, 1983)
●Taxonomy of Reverse Engineering (Chikofsky
&Cross, 1990)
●WCRE (Working Conference on R.E., 1990)

15. BENEFITS OF REVERSE ENGINEERING
●Benefits
●maintenance cost savings
●quality improvements
●competitive advantages
●software reuse facilitation

16. DIFFICULTIES OF REVERSE ENGINEERING
●Gap between problem
/solution domain
●Gap between concrete
and abstract
●Gap between coherency/disintegration
●Gap between hierarchical/associational

17. SCOPE AND TASK OF REVERSE
ENGINEERING
●program understanding
Problem/Applica
tion
domain
Program/Implem
en.
domain
Mapping

18. SCOPE AND TASK OF REVERSE
ENGINEERING
●Redocumentation and/or document
generation
●Recovery of design approach and design
details at any level of abstraction
●Identifying reusable components and
components that need restructuring
●Recovering business rules
●Understanding high-level system
description.

19. Discovery of Abstraction &
Different Approaches
of Reverse Engineering
By, Sweta Sangam

20. DISCOVERY OF ABSTRACTION
●Discovery of abstraction in large system
●Maintenance purpose
●Evolution purpose
●Re-Engineering purpose

21. LEVELS OF ABSTRACTIONS
●Application
●Application concepts, business rule, policies
●Function
●Logical and functional specification, non-functional
requirement
●Structure
●Data and control flow, dependency graphs
●Structure and subsystem charts
●Architectures
●Implementation
●Symbol tables, source text

22. DIFFERENT APPROACHES
●Restructuring
●Transformation from one representation to another
at the same level,
Requirements
Design
Source code
Behavior

23. DIFFERENT APPROACHES
●Reverse Engineering
●Design Recovery
●reproduce all the info for understanding the system
●Re-documentation
●provide different views of the system
●Re-Engineering
●first phase --understanding the system
●second phase--forward engineering

24. DIFFERENT APPROACHES
Abstraction
System
Old system New System
Forward Engineering
Re-Implementation
Reverse Engineering
Abstraction

25. Practical Implementation
& Tools of
Reverse Engineering
By, Debdeep Kundu

26. REVERSE ENGINEERING TOOLS
●Analysis Tools
●Browsers
●Object Server
●Task Oriented Tools

27. EXAMPLE--JAVA DECOMPILER
●How to recover bytecode from .class file
under Unix/Win with JDK?
% javap -c <filename>
% javap -help (to see the options)
●Java Decompilers
●”ClassCracker” http://www.pcug.org.au/~mayon/
●“DeCafe Pro" from DeCafe, France at
http://decafe.hypermart.net/index.htm
●“SourceAgain" from Ahpah corp at http://www.ahpah.com

28. EXAMPLE--JAVA DECOMPILER
●ClassCracker 2 Interface

29. EXAMPLE--JAVA DECOMPILER
●Components of ClassCracker 2
● Java decompiler
●retrieves Java source code from Java class files
● Java disassembler
●produces Java Assembly Code
●A Java class file viewer
●displays Java class file structures.

30. EXAMPLE--JAVA DECOMPILER
●Features of ClassCracker 2
●User visual interface.
●Can decompile class files within zip or jar files.
●Conversion mode (JAVA, JASM or JDUMP) is
selectable
● A Batch Mode allows multiple class files to be
decompiled simultaneously
●more…...

31. EXAMPLE--JAVA DECOMPILER
●ClassCracker 2 System Requirements
●All platform (Window/ Linus /Unix)
●JDK /JRE
●Do not believe it?
●From myClass_origin.class ==>myClass.java
●% javac myClass.java (==>myClass.class)
●% diff myClass.class myClass_origin.class

32. EXAMPLE--JAVA DECOMPILER
●ClassCracker 2.0--want to try it?
●Free download at
http://www.pcug.org.au/~mayon/classcracker/cc
getdemo.html
●Only first three methods are decoded.
●Bridge 1.0---Free
●http://www.geocities.com/SiliconValley/Bridg
e/8617/jad.html

33. CONCLUSIONS
●Reverse Engineering is a new research area
among software maintenance
●RE includes activities of understanding the
system and recovery info from system
●Program understanding is the most important
subset of Reverse Engineering
●Discovery of abstraction is key issue

34. REFERENCES
●http://www.wiley.com/WileyCDA/WileyTitle/
productCd-0764574817.html
●http://www.google.com
●- http://jode.sourceforge.net

35. THANK YOU

36. QUESTIONS ?