2. Introduction
Extension for Google Chrome.
Privacy protection system for online chat.
Encrypts chat text using 128 bit AES.
Decrypts at the receiver.
Common password for both users.
3. Motivation
No existing cheap solution.
Lot of Information analyzers in use for advertisements.
No freedom against governments – filter key words
For people who do not trust on servers. (Like me )
4. Design and Implementation
Design – JavaScript and HTML
Run as an extension in web browser – In Application
Layer.
5. Design and Implementation
At each end Encryption/Decryption occurs.
Cipher text in Base-64 encoded is sent via network.
6. Design and Implementation
Encryption – change text to Base-64
Decryption – show text in tooltip and copy to
clipboard.
7. Design and Implementation
Setting Password
Step 1 – Convert password to ASCII numeric
Step 2 – Get MD5 digest of ASCII as key.
Encryption
Step 1 – Identify the text box in focus and convert the
text string to ASCII numeric
Step 2 – Break it into 128 bit blocks. Assign nulls for
padding.
Step 3 – Apply AES 128 block cipher using key.
8. Design and Implementation
Step 4 – Convert encrypted numeric values to base 64
character encoding.
Step 5 – Replace original string with this. This will be
sent via server.
Decryption
Step 1 – Select received text and convert to numeric
values.
Step 2 – Break into blocks.
9. Design and Implementation
Step 3 – Apply AES 128 decryption to each set of
blocks.
Step 4 – Remove padding nulls from the result.
Step 5 – Convert to ASCII characters and show in a
tooltip while copying it to clipboard.
Ending Session
Replace the variables with key value with another
value.
16. Demonstration
When want to end conversation – End Session
Select “End Session” from menu and confirm.
17. Conclusion
Simple and cheap way to communicate confidentially.
But impossible to send emoticons.
No key sharing mechanism.
AES 128 simple cipher is vulnerable to language
statistics based attacks.
Therefore
Could and should be developed more for commercial
use.