During their whole life cycle, legal actions often require authentication of date and time of each intermediate step. That rule is constant from creation till archive, including possible in between ownership transmission. When referring to "dating" acts or documents, law often requires a date that is "undeniable /certain".
Information and Communication Technology manages time for its own purpose. Date-time stamp is used and depicts date and hour concatenation whereas time in ICT domain is valued in fraction of seconds rather than days.
The purpose of this paper (in French) is to instruct the reader with legal and technical constraints regarding time management; it also suggests thoughts to satisfy the two domains of requirements related to electronic messages with legal channel and to think over practical ways toward quick implementation.
A short reminder regarding legal and technical aspects of time management principles is followed by a first part that describes different stages of date-time stamp needs respectively to each step of electronic message life cycle.
The second part is detailing the advanced form for secure date-time stamping that describes the contribution of a trusted third party, the relevant code of practice and the suitable professional organization.