To protect your identity and confidentiality, do not use any devices owned by the company or the government to blow the whistle. For example, do not use a company or government-issued technology, including phones, computers, or wireless networks. The U.S. Supreme Court permits highly intrusive surveillance through corporate-owned property regardless if that property is given an employee to use in a personal capacity.
The best way to protect your confidentiality is to work with a whistleblower attorney. The attorney-client privilege protects the conversations you have with your attorney.