A method and device for managing an emergency procedure of an emergency transaction mode that can be activated in the event of a computer attack on or a failure of a transaction network. The method may be carried out by an electronic device suitable for performing a transaction in a normal mode or in the emergency mode. The method performs operations that may include receiving an activation command for activating the emergency mode procedure, where the command includes an identifier of the procedure and first encrypted data; verifying the activation command, which includes verifying the first encrypted data; and if verification of the command is successful, activating the emergency procedure.