Abstract: For a set (Lk) of embedded systems, an authorized operator with identifier (OPj) creates a mother public key (KpM) and a mother private key (KsM). The identifier (OPj), the range of identifiers referenced (Lk) and the mother public key (KpM) are published. For each embedded system (SNi), a diversified key (KsMi) is created from the identifier (SNi) and stored. For every public key (Kp) generated by an embedded system, a cryptographic control value (Sci) is calculated on the public key (Kp), an algorithm identifier (CA1) and the utilization parameters (U) of this key, using a zero knowledge signature algorithm, and a certification request message (MRCA) that includes control value (Sci), the identifier of the operator (Opj), and identifier (SNi) is transmitted to a certification authority, which retrieves the identifier (Opj) and the value of the mother public key (KpM).

Abstract: The present invention relates to a key recovery process used for strong encryption of a message sent by an entity, which message is either to be stored locally or transmitted to another entity, the reading of a message requiring a decryption key which can be reconstructed at least by a trusted third party for key recovery, while added to the message are a compensation field and a compulsory control field which itself comprises at least one key recovery field for allowing at least one trusted third party to supply the decryption keys that enable the encrypted message to be read. This key recovery process is remarkable in that the compulsory control field also comprises, in unencrypted form, the current date as well as the agreement number of the encryption hardware/software and, encrypted under a daily intermediate key, the dialogue key.

Abstract: The present invention relates to a key recovery process used for strong encryption of a message sent by an entity, which message is either to be stored locally or transmitted to another entity, the reading of a message requiring a decryption key which can be reconstructed at least by a trusted third party for key recovery, while added to the message are a compensation field and a compulsory control field which itself comprises at least one key recovery field for allowing at least one trusted third party to supply the decryption keys that enable the encrypted message to be read. This key recovery process is remarkable in that the compulsory control field also comprises, in unencrypted form, the current date as well as the agreement number of the encryption hardware/software and, encrypted under a daily intermediate key, the dialogue key.

Abstract: The present invention relates to a process for verifying the preservation of the integrity of an unprotected request sent by an anonymous client to a server, in which only one public key, that of the server, is used.

Abstract: A method for authenticating a user working in a distributed environment in the client/server mode, wherein each authentication is performed from a single piece of authentication information, known as the "passphrase", having a predetermined length and duration of use (as a function of a tally value). The method is applicable to either a one-time password (OTP) system or an OTP system integrated with a Kerberos system, or in a one-time password system used alone, and the method may be used from a trusted terminal or an untrusted terminal. A method is provided that enables reinitializing the "passphrase" at the end of the duration of use with security, even in the event of active interception, and either in an OTP system integrated with a Kerberos system, or in an OTP system used alone.

Abstract: A method for obtaining at least one securitized cleartext attestation by at least one requestor subject coupled to a data processing system and communicating with each other through a network. The data processing system includes a plurality of subjects and an authority represented by at least one server acting on behalf of the authority and issuing attestations. The requestor subject sends the authority an attestation request including at least one protection datum. The requestor subject chooses, at random, a check datum which is associated and linked with the protection datum. The requestor subject then transmits, in cleartext, to the authority both a piece of identification information defining the relationship between the check datum and the protection datum, and the protection datum itself. The server organizes the attestation in the form of binary information and calculates at least one of a signature and a seal of attestation taking into account the protection datum and the identification information.