Method for carrying out secure transactions over a network, especially using a mobile phone, whereby an audio, video or document file is encrypted with a purchase issued a corresponding encryption key

摘要

Method has the following steps: supply, prior to any transaction, of supplier data for creation of an encryption key; selection (140) of a digital object by a user from a supplier server; encryption (190) of the digital object using the user transaction key; transmission of the encrypted digital object to the user; decryption of the object using the transaction key; and use or reading of the object by the user at his terminal. The invention also relates to a corresponding system and a method for using the system with a mobile phone.