A system for managing sessions of secure electronic correspondence between at least one sending user and at least one receiving user, said system comprising: - at least one directory server (1200, 1201, 1202); - at least one electronic correspondence domiciliation server (1300, 1301, 1302) comprising a private management office (1310, 1311, 1312) for each user, particularly for choosing at least one correspondence counterpart, validating the content of the item of correspondence to be sent and storing the item of correspondence once sent; - at least one server for processing said items of correspondence (1700, 1701, 1702), and at least one electronic correspondence certification server (1500, 1501, 1502), said system being characterized in that: - said at least one domiciliation server (1300, 1301, 1302) further comprises at least one electronic correspondence sessions management module (1340, 1341, 1342) comprising at least one authorization submodule for the opening of a session between a user (1101, 1102) and his private management office (1310, 1311, 1312) on condition of verifying by request, before said opening, with at least one certification server (1500, 1501, 1502) that the sum of the scores of the digital identities of said user (1101, 1102) and of its counterpart (1102, 1101) exceeds a threshold set by a correspondence certification service provider, PSC-COR, which manages said at least one certification server (1500, 1501, 1502); - and in that said authorization submodule for the opening of a session is configured to execute a strong authentication function of a user of said system by verifying the matching of a code provided by the user to the domiciliation server with a single secret transmitted in two different forms by the certification server, on one hand to the domiciliation server and on the other hand to said user, this second transmission being over a communication channel which is different from that by which the user connects to the management server, the output of the strong authentication function conditioning a continuation of the opening of the session. - at least one directory server (1200, 1201, 1202); - at least one electronic correspondence domiciliation server (1300, 1301, 1302) comprising a private management office (1310, 1311, 1312) for each user, particularly for choosing at least one correspondence counterpart, validating the content of the item of correspondence to be sent and storing the item of correspondence once sent; - at least one server for processing said items of correspondence (1700, 1701, 1702), and at least one electronic correspondence certification server (1500, 1501, 1502), - said at least one domiciliation server (1300, 1301, 1302) further comprises at least one electronic correspondence sessions management module (1340, 1341, 1342) comprising at least one authorization submodule for the opening of a session between a user (1101, 1102) and his private management office (1310, 1311, 1312) on condition of verifying by request, before said opening, with at least one certification server (1500, 1501, 1502) that the sum of the scores of the digital identities of said user (1101, 1102) and of its counterpart (1102, 1101) exceeds a threshold set by a correspondence certification service provider, PSC-COR, which manages said at least one certification server (1500, 1501, 1502); - and in that said authorization submodule for the opening of a session is configured to execute a strong authentication function of a user of said system by verifying the matching of a code provided by the user to the domiciliation server with a single secret transmitted in two different forms by the certification server, on one hand to the domiciliation server and on the other hand to said user, this second transmission being over a communication channel which is different from that by which the user connects to the management server, the output of the strong authentication function conditioning a continuation of the opening of the session.