The method of securing data transfer comprises: a step of attempting to transmit a document from a document sender to at least one document recipient, by implementing at least one transmission attribute and for at least one step of attempted transmission, a step of evaluating the value of at least one transmission attribute and a step of making the evaluation of the value of the transmission attribute available to the sender. Preferably, in the course of the evaluating step, the evaluation is dependent on the anomalies of correspondence that are observed for each attempted transmission. Preferably, in the course of the evaluating step, the evaluation is, moreover, dependent on the elements provided by the recipient in the course of a step of registering with an electronic document transmission service.