Electronic signature in Bulgaria: the QES key (BORICA / B-Trust)

What is a QES key?

The QES — for Qualified Electronic Signature — is the highest level of electronic signature recognised by European law.

In practice, it is a personal digital certificate, usually stored on a secure device (smart card, USB token or, increasingly, a secure mobile app), which lets you sign documents and online procedures with full legal value.

In Bulgaria, this certificate is essential as soon as you want to run your company without delegating every click to a third party. Without it, you cannot file your own annual accounts, submit a digital tax return or access many public portals. That is why the QES key is an integral part of the journey described in our guide forming an EOOD 100% remotely: the steps.

The QES key works the same way whatever the form of your company. For a 100% remote formation, with no capital deposit or prior bank account, the DPK/EDPK is often the simplest choice; the EOOD/OOD remains the classic form with a capital deposit — see EOOD, OOD or DPK to choose.

eIDAS, BORICA, B-Trust: who does what?

Three names come up systematically; it is worth telling them apart:

In other words: eIDAS sets the European rules of the game, BORICA is the trusted Bulgarian operator that produces the signature, and B-Trust is the name of your certificate.

A B-Trust signature is therefore a fully fledged eIDAS QES, enforceable throughout the Union: it is Article 25(2) of Regulation (EU) No 910/2014 that establishes that a qualified electronic signature has a legal effect equivalent to that of a handwritten signature (eur-lex.europa.eu — eIDAS Regulation).

BORICA, which also operates the Bulgarian interbank system, is listed on the EU Trusted List of qualified providers; B-Trust is among the most widely used certificates in the country and the best integrated with the tax authority's (NRA) portals.

What is it actually used for?

The QES key is not an administrative gadget: it is one of the tools that turn a Bulgarian company into a structure genuinely manageable remotely — alongside a dedicated web interface to read your banking SMS (OTP / 2FA codes) live from any device, your Bulgarian mobile line and your local point of contact, all of which Fenchell operates for you. Its everyday uses:

• Commercial register — filing the annual accounts and corporate documents with the Bulgarian Commercial Register (linked to your EIK, the equivalent of the SIREN number).
• Tax authority (NRA) — signing and submitting VAT returns, corporate income tax returns and intra-Community recapitulative statements.
• Banks and fintechs — validating certain operations, agreements and online KYC procedures.
• Public portals — access to online services (BULSTAT, requests for certificates such as the Aktualno Sastoyanie, etc.).
• Contracts and documents — electronic signing of commercial contracts with the same evidential force as a handwritten signature.

How do you obtain a BORICA QES key remotely?

Good news: you do not need to travel to Bulgaria to obtain your key. Within the Eurotrade pack, obtaining the QES is built into the incorporation of your company and follows a clearly mapped journey:

1. Notarised power of attorney — you appoint Fenchell's local representative, via a notarised power of attorney compliant with the provider's template, to undertake the procedures on your behalf.
2. Identity verification — eIDAS requires an identity check before any qualified certificate is issued. Depending on the case, this is done by identifying the appointed representative or through a recognised remote identification process: your firm chooses the route suited to your situation, with no travel on your part.
3. Issuing the certificate — BORICA issues your B-Trust certificate, linked to your identity and your company.
4. Activation and delivery of the device — the key is configured and then made available to you to sign your procedures.

At Fenchell, issuing the key is part of the complete Bulgarian company formation journey. Once all your notarised documents are received, registration with the register takes at most 5 working days; the full process takes about 20 days (it depends mainly on you: signing at the notary and then sending the originals by DHL).

No travel, no queue in a Plovdiv office: your firm handles it on the ground.

What legal value and what security?

The strength of the QES rests on two guarantees. First, its legal value: under eIDAS, a qualified electronic signature produces the same legal effects as a handwritten signature, and this equivalence applies in all member states, France included.

A QES based on a qualified certificate issued in one member state is recognised as such in all the others (Article 25(3) of Regulation (EU) No 910/2014; eur-lex.europa.eu). A return or a contract signed with your B-Trust key is therefore fully enforceable.

Second, its technical security: the certificate rests on a secure signature-creation device and on the infrastructure of an audited qualified certification authority. In practice, your key is protected by a confidential code and tied to your verified identity: it cannot be used without you.

It is also an element of your company's economic substance, since it embodies a genuine and compliant administration — something banks value during KYC, unlike a "letterbox" structure. It is, moreover, one of the levers that ease the opening of a Bulgarian business bank account remotely.

In practice, most entrepreneurs delegate the everyday use of the key (NRA filings, annual accounts) to the bookkeeping handled by Fenchell, while keeping control of strategic signatures. The certificate has a validity term you set at order — 1 year or 3 years — and its renewal is tracked to avoid any compliance gap.

The QES, one building block of a system designed as a single whole

On its own, an electronic signature does not make a company genuinely operable remotely. And operability is not "bolted on" afterwards: at Fenchell, it is built in from the outset, within the file itself. Here, point by point, is what a generic incorporation delivers — and what the Eurotrade pack builds in:

General information current as of 8 June 2026, not constituting personalised tax, legal or accounting advice. Timeframes, validity terms and methods of obtaining are indicative and vary according to your situation. Fenchell Capital OOD — Bulgarian firm based in Plovdiv (EIK 207945095).