Tax advisersApplies to: Spain

Encrypted file exchange for tax practices

Send documents to clients and request documents from them – encrypted, no client account needed, with proof of when they were downloaded.

Developed & operated in Germany
End-to-end encrypted
Professional secrecy in our contract
Signed proofs of delivery

What your professional rules require

Art. 199 del Código Penal

Disclosing another person’s secrets learned through one’s work or employment is a criminal offence; professionals who breach their duty of confidentiality face a higher penalty and disqualification from practice.

Art. 5 de la Ley Orgánica 3/2018 (LOPDGDD)

Controllers, processors and everyone involved in processing personal data are bound to confidentiality – in addition to any professional secrecy, and beyond the end of the relationship.

How TEPHIA SECURE meets them

Contractual confidentiality

In clause 5b, our data processing agreement commits us to secrecy and limits access to what the service requires. Everyone involved is bound in writing in the same way before starting work. You conclude the agreement electronically and receive a copy as a PDF.

State of the art

AES-256-GCM encryption in the sender’s browser, with the key derived from the password using Argon2id. The server holds no key and cannot read the contents.

No account needed for recipients

Recipients do not need an account. Clients and third parties can send you documents through an upload box, with the same protection and the same proof of delivery.

Verifiable proof of delivery

Each entry is cryptographically chained to the previous one. The proof of delivery is a signed PDF/A with a timestamp from an independent time-stamping authority.

First page of the sample proof of delivery: download via the link in the email, IP address and location, checksum and verification stamp with QR code

See an example: a real proof of delivery A real transfer of three sample files to a demo recipient — digitally signed, timestamped, with the checksum of every file and publicly verifiable at any time.

Open proof (PDF) Verify online

How your proofs are secured

	In every planSignature with our certificate	Add-on · coming soonQualified electronic seal
Any change to the PDF invalidates the signature	included	included
Timestamp from an independent authority	included	included
Hash chain with daily chain seal	included	included
Checksum (SHA-256) of every file, confirmed by the recipient	included	included
Verifiable online, without an account	included	included
Display in Adobe Reader	“Validity unknown”¹	Valid
Legal presumption of authenticity (Art. 35(2) eIDAS)	not included	included
Useful for	Your records, clients	Courts, authorities, the other party

¹ Not an error: our certificate is not on the EU trust list that Reader recognises. You can check integrity online or using the certificate fingerprint.

Always included

Signature: any change is detected
Timestamp from an independent authority
Hash chain with daily chain seal
Checksum of every file, confirmed by the recipient
Verifiable online, without an account

Added with the seal · coming soon

Adobe Reader shows “Valid” instead of “Validity unknown”
Legal presumption of authenticity (Art. 35(2) eIDAS)
Useful for courts, authorities, the other party

There is no certification of services like this by a professional body, and carefully selecting a service provider remains your responsibility under your professional rules.

The information on the legal position on this page is general information, without any warranty as to completeness or currency, and does not constitute legal advice. Only our contracts are binding.