Blog Cyberjustice - The functioning and the using of the electronic signature

The electronic signature can be used in many different contexts such as electronic market, signature of official documents, and widely, many types of contracts. Electronic signature works with the technology of encryption and hashing and is regulated in Europe by the eIDAS regulation.

The electronic signature, how does it work?

It uses the technology of encryption associated with hashing.

Encryption is a system that gives the possibility to transform a classic message into an incomprehensible sequence of numbers in binary language (only 1 and 0). Everybody owns a public key and a private key. The public key is the one that transforms the message into the sequence that can be public because it’s unclear, encrypted and the private key is the one that makes the message clear once it reaches the addressee.

The technology of hashing consists in transforming a document in a formula of incomprehensible characters. Hashing a document is irreversible, but the same document will always give the same result of hashing, called an “hash”.

So now that we explain those to technology separately, we must join them. The electronic signature happened when you entered the public key on the hash of the document. To be sure that the document has not been altered, the addressee will first hash the document so he can obtain a hash, and enter his private key on the result of the signature to find the hash again. If the two hashes are the same, it means that the signature is valid, the integrity and the authentication guarantees.

What are the pros?

Despite the advantages of having a dematerialize procedure and an electronic storage, encryption, considering it’s out of misfunctioning, brings many guarantees. First, it proofs the authentication of the members who took part of the contract, or who signed the document in question. Second, it guarantees the integrity of the document, which means that no modification of the document could occurred and if it happens, it would be noticeable.

What does the law say about it?

There are two types of regulation, the European one and the French one. The European regulation “eIDAS”, signed in 2014, uniformized the rules of law in Europe including electronic signature. It creates four levels of security a signature can guarantee. To reach the highest level, the authority or society who delivers the electronic signature must obtain the title of “qualifying”, given by a “qualified trust service provider ». The entity can now sign with a “qualified electronic signature”.

In French law, the Code civil, considers in its article 1366 that the electronic signature can be used as a proof as much as the written signature if it respects the identification of the persons who took part in the signature and the integrity guarantee.

Today the best way to satisfy the condition of this article is to have a qualified electronic signature in the European meaning. Furthermore, using this security like signature creates a presumption of its validity in front of a court.

Julia BERTHAUD

M2 Cyberjustice – Promotion 2024/2025