This document discusses code obfuscation techniques used to protect intellectual property and hide malicious code. It describes general obfuscation methods like control transformations, computation transformations, and data abstraction obfuscation. Specific techniques are outlined like opaque predicates, inheritance modifications, variable splitting, and method inlining/cloning. Code obfuscation aims to complicate reverse engineering but cannot completely prevent it, and it decreases performance. When used judiciously, obfuscation provides some protection against theft and malware insertion.

1. Code
Obfuscation
Amol Kamble

2. Why We Need Code
Security?

3. How
Decompilation
works?

4. “ Code obfuscation is the practice of
making code unintelligible , or at the
very least, hard to understand ”
“General code obfuscation techniques
aim to confuse the understanding of
the way in which program functions.”

5. Who use the Code Obfuscation?
 code obfuscation is used to protect
intellectual property by software
companies.
 it is also used extensively by authors
of malicious code to avoid detection
from virus scanner.

6. Obfuscation Quality
 Potency
 Resilience
 Stealth
 Cost

7. General Methods for Obfuscation

8. Obfuscating control
transformations
 Aggregation transformation
 Control ordering transformations
 Computation Transformation

9. Computation Transformation
As the number of predicates increase in a body of code, insertion of
dead or irrelevant code into the program becomes easier.
Inserting Opaque Predicate

10. Computation Transformation
obfuscate a loop

11. Obfuscating data abstractions
 Modifying inheritance relations
 Restructure Arrays
 Obfuscating Procedural Abstractions
 Inline and Outline Methods
 Clone Methods
 Obfuscating built-in data types
 Split variables
 Convert static to procedural data
 Merge scalar variables

12. Modifying inheritance relations
The complexity of a program increases with
greater depth of the inheritance tree.
Along these lines, we can artificially increase the
complexity of a program
 Increasing Depth of Inheritance
 Introducing Bogus Classes

13. Merge Scalar Variables
 This method of obfuscation involves merging two
or more scalar variables into a single variable.
 The variables v1, v2 . . . vk can be merged into one
variable Vm provided the the combined ranges of
v1, v2 . . . vk fit within the precision of Vm.

14. Converting Static Data to
Procedural Data

15. Split Variables
 Variables of restricted range can be split up into two or
more variables.
 In order to split a variable V of type T into two variables
p and q of type U,
 1. A function f(p,q) that maps the values of p and q into
the corresponding value of V.
 2. a function g(V) that maps the value of V into the
corresponding values of p and q.
 3. new operations cast in terms of operationson p and
q.

16. Inlining and Outlining
Methods

17. Clone Methods
ADD()
{
int a=1,b=2,c;
c=a+b;
}
---------------------------------
ADDITION()
{
int a=1,b=2,c;
c=a+b;
}
----------------------------------
AddTwoNumber()
{
int a=1,b=2,c;
c=a+b;
}
Program :
{
Add();
.
.
Addition();
.
.
.
AddTowNumber();
}

18. Code obfuscation by obstructing
static analysis of programs
 Control-flow Transformations
 Data-flow Transformations

19. Code Obfuscation in
Disassembly Phase

20. Code Obfuscation in
Disassembly Phase
 Thwarting disassembly
 Junk Insertion
 Thwarting Linear Sweep
 Thwarting Recursive Traversal
 Branch functions
 Call conversion
 Opaque predicates
 Jump Table Spoofing

21. Code Obfuscation as it Relates
to Viruses

22. Code Obfuscation as it Relates
to Viruses
 Virus Types
 Polymorphic
 Metamorphic
 Obfuscation Techniques
 Dead Code Insertion
 Code Transposition
 Register Reassignment
 Instruction Substitution
 Comparisons
 Another Angle

23. Conclusion

24. Conclusion
 No obfuscation has yet been found that can
completely resist reverse engineering.
 Code obfuscation increases the code decreases
performance, and can hinder certain compiler
optimizations.
 when used sparingly, and combined
appropriately, can add a layer of protection
against theft and insertion of malicious code

25. How much Attention should be
given to Software Protection?
Software
Users
Group 1
True Client
Who buy
software
license.
Group 2
Client ,
Programmers.
Group 3
Professional
Hackers.

26. Thank you!!!