Abstract: The method allows a sender to safeguard its identification in messages sent to a recipient. Even when using promiscuous channels for transmitting the message, only the recipient is able to disclose the sender's identity. The method uses symmetrical cryptography of low computational requirements, without depending on a single shared key among the users so that the sender cannot disclose the identity of the others. The method gradually safeguards the sender's identification, by using successive symmetric cryptographic operations and keys of a binary tree structure built for this purpose in the recipient which applies the steps in a reverse way to that of the sender's protection, to disclose its identification. It is also possible to encrypt the message body.

Abstract: A user accesses an intermediary device, in communication with a restricted entity, requires a One Time Credential OTC and activates a mobile device previously registered, by the user, in an authentication entity, in order to generate a OTC, based on the information related to the user, to the restricted entity, to the mobile device and to the authentication entity, the OTC credential being then typed in the intermediary device and transmitted therefrom to the restricted entity and, from the latter, to the authentication entity, in which the OTC credential is decrypted and compared with the information related to the user, to the restricted entity, to the authentication entity and to the mobile device registered in the authentication entity, in order to generate an authentication result which is transmitted to the restricted entity, which will decide to accept or to reject the access of the user.