Method for managing at least one transaction implemented by an electronic payment terminal having a magnetic stripe reader for the reading of a paycard of a user (U), characterized in that it comprises the following steps implemented in a secured remote server : • a step for receiving, from said electronic payment terminal , at least one transaction message carrying at least one piece of data of said payment card of said user (U), read by said magnetic stripe reader and encrypted by said electronic payment terminal , and at least one identifier of a mobile communications terminal of said user (U); • a step for sending, to said mobile terminal corresponding to said identifier, at least one transaction validation request message carrying at least one piece of information representing said transaction; • a step for receiving, from said mobile terminal corresponding to said identifier, at least one validation message carrying at least one response to said validation request message; • a step for managing said transaction if said response is positive; and a step for securing said transaction comprising the following sub-steps: • transmission of at least one securing code, by a server of a bank organization corresponding to said bank card of said user, to said mobile terminal; • reception by said secured intermediate server of said securing code coming from said mobile terminal; and the following steps implemented by said mobile terminal of said user: • loading of a multimedia application; • reception and processing by the multimedia application of the transaction validation request message; • display, on the mobile terminal of said user, of a user interface presenting the user with a validation means; • transmission, to said secured intermediate server, of said validation message if the user has accepted the transaction via said validation means. • a step for receiving, from said electronic payment terminal , at least one transaction message carrying at least one piece of data of said payment card of said user (U), read by said magnetic stripe reader and encrypted by said electronic payment terminal , and at least one identifier of a mobile communications terminal of said user (U); • a step for sending, to said mobile terminal corresponding to said identifier, at least one transaction validation request message carrying at least one piece of information representing said transaction; • a step for receiving, from said mobile terminal corresponding to said identifier, at least one validation message carrying at least one response to said validation request message; • a step for managing said transaction if said response is positive; • transmission of at least one securing code, by a server of a bank organization corresponding to said bank card of said user, to said mobile terminal; • reception by said secured intermediate server of said securing code coming from said mobile terminal; • loading of a multimedia application; • reception and processing by the multimedia application of the transaction validation request message; • display, on the mobile terminal of said user, of a user interface presenting the user with a validation means; • transmission, to said secured intermediate server, of said validation message if the user has accepted the transaction via said validation means. <EOS>