Intellectual Property & Software Startup

I work for a large financial services organization. If I start to develop a piece of software that I later want to start up as a software company, is there any way to prevent my current company from securing rights to my software without explicitly executing a signed agreement ?

The software would not be directly related to my job responsibilities and I would not be using company resources to develop the software.

What if I put my new company under a family member's name ? Any other options ? I do not believe my current company would entertain an "opt out" agreement for rights to the software.

I want to protect my intellectual property and I do not want to give up the idea of starting my own company in the not to distant future.

Any advice is greatly appreciated.