You will, however, be bound by current 'lawful intercept and storage' laws. If you provide a remote computing service (email, hosting, cloud storage, fitness tracking, etc) you will be bound by 18 U.S.C. § 2703(f) [1]. If you provide telecommunications you will be bound by CALEA [2]. You will be bound by the Stored Communications Act and by the Patriot Act, and you will be bound to provide access to the core of your service and/or your private keys if you are given an NSL.

Essentially - you can not provide secure communication as a service.

If you try to provide it as a product it's more blurry. With precedents like Blackberry, RSA and Skype you need to make sure you're operationally able to deal with extreme levels of leverage and influence.

[1] http://www.law.cornell.edu/uscode/text/18/2703

[2] https://en.wikipedia.org/wiki/Communications_Assistance_for_...