Abstract: In order to control the authorisation of a user during an attempt to access an IP transport network (5) by means of an access network (1, 2), a user terminal (11, 12, 13) emits an access request to an access supplier (6, 7, 8), containing data for authenticating the user to the access supplier, and said request is then transmitted to an access server (9) of the access network (1, 2) in view of being addressed to a remote authentication server (15) of the access supplier. On reception of the access request, the access server (9) emits a RADIUS request to a proxy server (10) of the access network (1, 2) which determines whether the user must be locally authenticated, and if this is the case, the proxy server transmits, to the access server (9), a request for authentication data to be addressed to the terminal of the user, and carries out a local procedure to authenticate the user, on the basis of the authentication data supplied by the user.

Abstract: After a preliminary exchange between the vendor and the purchaser with a view to completing a transaction corresponding to the payment of an amount due to the vendor for a service rendered, information is exchanged only between the purchaser and a telepayment server (T). The purchaser sends the telepayment server information (1) including data relating to the vendor and said amount. The server then authenticates the vendor's identifier (I1) on the basis of the information received and responds by sending the purchaser a message (2) instructing payment of said amount and including at least said amount and the identifier (I1) of the vendor. The purchaser responds by sending the server confidential information (3) enabling payment of said amount, after verification by the purchaser of the identifier (I1) of the vendor.

Abstract: The proof is provided by means of the following parameters: a public module n formed by the product of f prime factors pi, f>2; a public superscript v; m base numbers gi, m>1. The base numbers gi are such that the two equations: x2?gi mod n and x2??gi mod n cannot de solved in x in the ring of integers modulo n, and such that the equation xv?gi2 mod n can be solved in x in the ring of integers modulo n in the case where the public superscript v is in the form v=2k, wherein k is a security parameter.

Abstract: A photoreceiver for frequency-modulated optical signals. The photoreceiver is formed of a semiconductor laser of the FABRY-PEROT type, wherein one of the faces thereof which receives a frequency modulated light beam is given an antireflection treatment. The voltage at the laser terminals is also tapped. Such a device finds particular application to optical telecommunication systems.

Abstract: A method and circuit for processing digital signals representative of vectors that permits processing between pairs of vectors of sets of vectors for ensuring the meeting in space and time of these vectors. This meeting is effected using parallel processing in a two-dimensional network of cells for processing the component assigned to a dimension of the network, and sequentially by partitioning the sets into sub-sets subjected to processing during a microcycle, during which a sub-set is stored. A sub-set is stored during a macrocycle for the next processing and so on. Vectors can consist of tuples of a data base.

Abstract: Said medium is a halide glass (2, 8, 12, 20) containing uranium ions at least partly in the form U.sup.3+ and having, at least at one point of a region of the near infrared between 2.2 and 3.4 micrometers, an optical attenuation not exceeding 0.01 cm.sup.-1. For the production thereof, preparation takes place of a halide glass containing uranium ions, at least partly in the form U.sup.4+ and/or U.sup.5+, and having at least at this point the aforementioned attenuation. The glass is exposed to ionizing radiation able to produce trivalent uranium ions from the uranium ions of the prepared glass. Application to the production of optical guides, whereof the guiding parts are formed from such a medium.