Recently, "Privacy Policies" have become very popular. We'd had one for 18 years and it has been included in our standard agreement with all clients. It protects both your company and ours:

"PRM shall protect the confidentiality of your confidential company data which may be revealed to it during the course of study, data collection, or analysis. You agree that neither you nor your company employees will release any computer programs, computer output, instruction manuals, reports or other material supplied by PRM to any third parties. Either party may reveal the existence of this agreement, but both parties agree to hold its terms and conditions confidential."