can I safely share my EU login key to have it submitted on my behalf

Sharing your login key is not necessary to authorize a third party

No, it is not necessary to provide your personal login key or password for the EU information system in order to have someone submit on your behalf. The system is specifically designed to allow a market participant to authorize a third party to submit without handing over their own login credentials. This is an intentional function of the register, not a workaround that you yourself need to create by sharing a password.

In practice, sharing a key or password with a service provider means that the third party acts entirely under your identity in the system, without any distinction between what you did yourself and what the other party did. With an authorization, that distinction remains visible, and you remain the person who can see and manage who is active on your behalf. Those wishing to delve deeper into this matter can read more about authorization of a service provider to submit a due diligence declaration and about the steps that follow in submitting a due diligence declaration in the EU information system.

What this is based on: the register and the role of the market participant

Regulation (EU) 2023/1115 places the obligation to submit a due diligence declaration with the market participant or trader itself, and the EU information system for the deforestation regulation is the register in which that declaration is submitted and in which the identity of the submitting party is recorded. The structure of that register, as described on the European Commission page on the implementation of the deforestation regulation, provides for a framework in which a third party can act on behalf of the market participant without the market participant having to hand over their own access credentials. Who exactly has which role and obligation, and which data belongs with it, remains a question that is separate from the manner of submission; those seeking more guidance on this matter can read about the data that must be included in a due diligence declaration.