No employer may do any of the following:

1. (a) Require, as a condition of employment, that an employee refrain from disclosing information about the employer’s working conditions.
2. (b) Require an employee to sign a waiver or other document that purports to deny the employee the right to disclose information about the employer’s working conditions.
3. (c) Discharge, formally discipline, or otherwise discriminate against an employee who discloses information about the employer’s working conditions.
4. (d) This section is not intended to permit an employee to disclose proprietary information, trade secret information, or information that is otherwise subject to a legal privilege without the consent of his or her employer.