Understanding digital signatures and contract sealing
When a signee signs a contract, their digital signature authenticates in writing that they accept and validate the contents. Many countries worldwide accept digital signatures. In the European Union, the eIDAS regulation ensures adequate security for electronic transactions.
According to eIDAS, a digital signature cannot be denied legal effect solely because it is in electronic form.
A Qualified Electronic Signature carries the exact same legal weight as a handwritten signature.
How contract sealing prevents tampering
To understand how to check if a contract was changed after being signed, our sealing process provides the answer. When the final signee completes signing a contract, Contractbook generates a sealed PDF using PDF Advanced Electronic Signatures (PAdES).
The Electronic Seal: Guarantees that the contract’s content remains exactly as it was when the last signature was applied.
The Time Stamp: Proves the exact passage of time since the signatures were finalized. The timestamp is set to the last moment of the signature process.
Signature compatibility: Contract sealing does not affect your chosen signature type. If a contract is signed using SMS verification, the seal locks the document without changing the validity of the SMS signature.
The technical providers behind the seal
When Contractbook seals a document, it relies on two secure trust services:
Qualified Certificate for Electronic Seal: Issued by Buypass, a recognized Trust Service Provider, to ensure the document's origin and integrity.
Time-stamping service: Contractbook uses a Qualified Time Stamp issued by Certum, which is legally valid across all EU states.
Validate a digitally signed and sealed document
You can easily verify the signature validity and the electronic seal of your completed agreements manually.
Open your completed contract in Contractbook.
Download the signed contract as a PDF file.
Open the downloaded PDF in Adobe Acrobat.
Check the banner at the top of the document or navigate to the Signature panel to verify the certificate, authenticity, and the electronic seal.
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