Abstract: Method and device for the certification of a transaction A problem of the real-time revocation or neutralization of an X509 type certificate available belatedly in a public database (BD) is resolved by the direct neutralization, in a mobile telephone (1), of a sub-program (26) for the signing and/or transmission of certificates pertaining to transactions to be validated. It is shown that this action leads to neutralization within ten minutes following the signalization, or the neutralization request, whereas 24 to 48 hours are needed with normal administrative channels (AE, PB).

Abstract: A digital filter operating at intermediate frequency, having a transverse filter; a recursive filter; a device for storing the different coefficients of the two filters; a D-A conversion device situated at the output of this storage device; a device for addressing this storage device; and controls for the addressing device.