null Pune April 2012 Meet

1. Tmto pdf cracker

2. What is PDF
• Portable document format
• Open standard for documentation
• By adobe systems in 1993
• Complete description of fixed layout flat
document, text graphics ,fonts and other
information
• Was proprietary then became official in 2008

3. File structure
• 8 tyes of object
– Boolean
– Strings arrays
– Names
– Dictionaries
– Streams

4. Encryption
• What to encryption
• What to encrypt
• Types of encryption

5. Current techniques
• Bruteforce
– Trying each and every possible combination of
character set
• Dictionary
– Making list most possible list of password and
trying them.

6. Problems with current technique
• It takes days to recover password
• Resources needed to recover password are
much more
• Computation required are more

7. New concept
• TIME MEMORY TRADE OFF
– What is it?
– Why

8. Benefits of TMTO
• Less time to recover password
• Less computation required

9. Problems with TMTO
• Hash collision
• Huge disk space

10. Solution to problems
• Collusion avoidance technique
– Chaining
• Smart hashing
– Similar to dictionary attack

11. Internal Modules for recovery utility

12. Internal modules for RB
Generation

13. Advantages & Disadvantages

14. Future Development