I am fully prepared to sign my client's non disclosure agreement form. If the client doesn't have one, I can suggest one of mine which I will tailor to my client's specific application.
As a patent practitioner I am bound by the rules of the Patent Office to maintain confidentiality. The Manual of Patent Examination Procedures has a chapter on this topic. This can be found in CFR 37 section 10.57 of the MPEP.