Electronic signature of the internship agreements

Informative document · last updated: 2026-08-20

Internship agreements and their annexes are signed online and cryptographically sealed. This sheet summarises the process, its legal level, and the file each party receives.

1. How signing works

Each signer —the company and the student— reviews the document inside their authenticated portal session and captures a signature in one of three ways: drawing it on screen, typing it, or uploading the hand-signed PDF. Before signing they accept the applicable terms. The document is then closed with a PAdES electronic signature and a “Signatures certificate” page is appended.

2. Level under eIDAS

It is an electronic signature (EU Regulation 910/2014, eIDAS, art. 3.10) with a reinforced evidence package. Its admissibility and weight:

Admissible as evidence — an electronic signature “shall not be denied legal effect and admissibility as evidence in legal proceedings solely on the grounds that it is in electronic form or not qualified” (eIDAS art. 25.1). In Spain it is weighed as private documentary evidence under free assessment (art. 326 LEC).
Not qualified — we do not claim the presumption of equivalence to a handwritten signature (art. 25.2) or a qualified time stamp (art. 41). The closing signature is applied by a non-qualified trust-service provider.
Its strength rests on the evidence trail — identity + integrity + time + consent, chained tamper-evidently (see below).

3. What the evidence records

For every act (sign, decline, seal) and each party, the evidence ledger stores:

Declared identity	Name, identity document (DNI/NIF/NIE) and email address.
Signing capacity	Company, student or school — and, for the company, the representative who signs.
Date and time	The moment of each act, recorded in the evidence ledger.
Technical origin	IP address and browser (user-agent) used to sign.
Signing act	Type of captured signature —drawn, typed or scanned— and the corresponding image or record.
Consent	Version and text of the terms accepted at signing time.
Integrity	SHA-256 hash of the signed document and a hash chain across events, making the ledger tamper-evident.

4. Deliverable file format

The document is delivered as a PDF with an embedded PAdES electronic signature (ETSI EN 319 142), verifiable without relying on our servers. It includes:

A final “Signatures certificate” page: the parties, the captured signatures, the school’s seal, the sealing identifier, the document fingerprint, and a QR code + URL for public verification.
Online public verification at htlescueladeempresaonline.com/verificar/<code>.
Available to the parties in their portal at all times.

5. How to check the document

Open the PDF in Adobe Acrobat Reader: it confirms the document has not been modified since it was signed. Change a single byte and the signature stops validating. The European Commission’s EU DSS validator gives the same technical analysis on the PDF itself, without relying on our servers.

To additionally check the authenticity of the signing certificate (that it is the provider’s, not a certificate cloning the name): extract the certificate from the PDF (Adobe: signature properties → show certificate → export), compute its fingerprint with openssl x509 -in cert.pem -outform DER | sha256sum and compare it against the list published at seal.123automate.it/.well-known/seal-cert.

The closing certificate is the school’s own (self-signed). Trust-list validators —such as valide.redsara.es— will therefore flag it as “certificate not supported / not qualified”: this is the expected result (point 2), not an integrity failure. What this signature proves is the document’s integrity and the evidence package, not a qualified signature.

The closing signature is applied as a non-qualified trust-service provider (eIDAS art. 3.19).