Abstract: An encrypted signature S representative of the information and of the identity of the holder of the information is established by means of a calculation algorithm for the encryption and the compression of the information to be saved. The signature S is recorded on the medium carrying the information forming the message M. The parameters for the calculation of the signature S, one or several secret keys, are recorded on at least one inviolable carrying medium. The application is to qualitative safeguarding and protection of data, on-line or not, in data bases.