Developing software with Codeigniter and licencing

[eluser]Unknown[/eluser]
Hey,
I am currently in the process of working on a project and we are looking to use Codeigniter to develop the system. The system is going to be paid software, and the source code will be encrypted. Is this allowed under Codeigniter's licence? I know that Codeigniter will need to be referenced in the documentation, just wondering if there is anything else.

Regards,
Andrew