Digital signature of documents
Harmony Technology provides an electronic signature service. The “digital signature” is a computer mechanism, based on the use of cryptographic functions, to offer the same functions and guarantees as a handwritten signature. This conception is also known as “electronic signature” or “digital signature”.
Just like the handwritten signature of a paper document, the digital signature of an electronic document makes it possible to establish a link between the document and the signatory. The established association can therefore have several purposes defined by the document itself or by the context in which the signature is applied, for example:
- Identify the author of a document.
- Mark the signatory’s agreement to the terms of the document.
- Indicate that the document has been read by the signatory.
Technically, there are currently several standard formats for digitally signed documents. These formats define several levels of signatures. Each of these levels provides additional guarantees at the cost of an increased complexity of the signature format.
Simple signature formats, whose best-known representative is ” PKCS#7/CMS “, always provide the following guarantees:
- Identify the signatory: a signature makes it possible to reliably identify the identity of the person who signs the document.
- Document integrity: the signature verifies that the document has not been altered since the signature was created.
- Weak non-repudiation of the signatory: the signatory cannot deny having signed the document unless the means of signature used is compromised.
For example, if a user uses his electronic identity card to electronically sign a document, he cannot later on deny having signed the document unless he can prove the theft or piracy of his electronic identity card.