The present invention provides a system and a method for generating digital signatures. The system comprises a first formula which generates the signature as selected series from at least two, but preferably more digitized biometric features of a user. The signature comprises a different selected series per unit of time of for instance 10 seconds. The invention comprises a second formula which assigns a numerical value to a data file. The second formula can also use the numerical value to define another time interval, on the basis of which another signature can be generated. The invention further provides a number of examples for application of the generated signature during the sending of data files.