Modify Google Extension for Decrypted Cookies

I need a JavaScript Google Chrome extension modified. The extension currently downloads encrypted cookies from the IRCTC website. I want it modified to download decrypted cookies instead.

Requirements:
- Use provided encryption schema to decrypt cookies.
- Add logging feature to record download details.
- Rename the extension to "GADAR".

Ideal Skills:
- Proficiency in JavaScript and Chrome extension development.
- Experience with encryption and decryption.
- Ability to implement logging functionalities.

Please ensure the modified extension is secure and maintains performance.