You should ask employees and suppliers to sign a non-disclosure/confidentiality statement committing to confidentiality/confidentiality of personal data in the performance of their work. In this way, you guarantee the security of personal data within the scope of your work.
Example:
In my capacity as an official/employee of the authority/company __________, I, the undersigned ___________, declare that I will respect the confidentiality of all personal data for which I have the right and authorization to access and which are kept in the collection of personal data in the authority/company where I perform my work job position, and that I will process personal data only for specific, legally prescribed purposes, in accordance with the Law on the Protection of Personal Data, and especially in accordance with the principle of confidentiality from Article 9 of the law.
I also undertake not to submit or in any other way make available to third parties the personal data for which I have the right and authority to access (unauthorized disclosure), and I undertake to maintain the confidentiality of the personal data and after the termination of the validity of the authorization to access personal data.
I am aware that any unauthorized disclosure of personal data to which I have the right to access within the scope of my work constitutes a violation of work and ethical obligations.

