Digital Signature

Yes. Today, writing in electronic form is accepted as evidence in the same way as writing on paper, provided that the person from whom it emanates can be duly identified and that it is drawn up and stored in conditions of to guarantee its integrity. The legislation (and in particular article 1316 of the civil code) defines the digital signature as “the use of a reliable identification process guaranteeing its link with the act to which it is attached”.

The electronic signature mainly offers: 1. the possibility of signing a document without printing it (paper saving); 2. the possibility of sending the document by e-mail (saving of stamps); 3. the possibility of signing a document without meeting (reduction of travel); 4. the possibility of keeping the document in digital format (simplification and elimination of paper archiving);

The digital signature differs from the written signature in that it is not visual but corresponds to a number or a sequence of numbers. Indeed, the signature operation applies to a file and produces binary information commonly called an electronic or cryptographic signature. This will not only be linked to this file but also linked to the person who made the act of signing. That said, a certain number of software programs, in particular Adobe Reader, automatically check each signature when the document is opened and display a visual validation message, which still makes it possible to materialize the digital signature.

Whatever its format, it is very easy to modify the content of a digital file to one's advantage without leaving a trace and without knowing who modified it. The other side of the coin is that it is impossible to affix a reliable identity to an electronic document, simply without a specific tool. It is therefore necessary to appeal to cryptology, which is, etymologically, the “science of secrecy”. It encompasses cryptography — the secret writing — and cryptanalysis — the analysis of the latter. The electronic signature as well as all the mechanisms for managing electronic evidence are entirely based on this science.

You can sign all types of files without exception (word files, PDF, jpg, XML, etc.). That said, a good practice is to use the very widely used PDF format, which offers good document stability and allows several electronic signatures to be embedded.

No ! Contrary to popular belief, a signing operation does not encrypt or encrypt the document. It doesn't change it either. The document remains readable in plain text by your usual software.

The electronic signature makes it possible, for a digital document, to guarantee: 1. the identity of the signatory; 2. the non-repudiation by the signatory of the signed document; 3. the integrity of the signed document, i.e. its absence of modification.

To electronically sign a digital document, you need : - the document in question; - an electronic signature software or online service; - a verified digital identity or an electronic certificate.

The production of a cryptographic electronic signature requires the use of what is commonly called an "electronic certificate". This electronic certificate is similar to a digital identity card that can be used to certify a person's identity with certainty. It enables digital documents to be signed with the guarantee that the identity of the signatory is recognised without any ambiguity or dispute. In concrete terms, it is an electronic file containing a certain amount of personal information (surname, first name, etc.) as well as a private key enabling cryptographic signature operations to be performed. It can be materialised either in the form of a simple software file, or in the form of a hardware device (smart card, SIM card, cryptographic USB key, token), or in a dematerialised form (Cloud).

The electronic certificate is issued by a Certification Authority, whose role is to verify the identity and link the private signature key to the identity of the signatory. The issuance of a signature certificate requires a number of identity verification operations: - at least the sending of photocopies of identity documents for the most flexible procedures; - a physical visit by the applicant to the certification authority and a face-to-face identity verification for the most advanced certification policies. At this stage, the applicant presents his or her identity papers in exchange for the certificate.

To sign a document, you will generally have to carry out a number of steps: - view the document to be signed; - click on a "sign" button; - select the certificate or insert it in your computer if it is a USB key; - type in a PIN code; - validate.