Abstract: To check a digital signature, using a microcircuit card, the microcircuit being designed to receive and to process requests to check digital signatures, the process comprises storing in a memory in the microcircuit a certificates table containing digest forms of authorized public keys, and a phase of checking a digital signature consisting of: receiving by the microcircuit the digital signature to be checked and a public key corresponding to a private key that was used to generate the digital signature to be checked; calculating a digest form of the received public key, searching for the calculated digest form of the public key in the certificates table, and decrypting the digital signature using the received public key if the calculated digest form of the public key is located in the certificates table.

Abstract: To check a digital signature, using a microcircuit card, the microcircuit being designed to receive and to process requests to check digital signatures, the process comprises storing in a memory in the microcircuit a certificates table containing digest forms of authorized public keys, and a phase of checking a digital signature consisting of: receiving by the microcircuit the digital signature to be checked and a public key corresponding to a private key that was used to generate the digital signature to be checked; calculating a digest form of the received public key, searching for the calculated digest form of the public key in the certificates table, and decrypting the digital signature using the received public key if the calculated digest form of the public key is located in the certificates table.

Abstract: The invention relates to a method and device for generating a large static image M(n), such as a sprite or a mosaic, from a video sequence including successive video objects. This method comprises a first step for estimating motion parameters related to the current video object V0(n) of the sequence with respect to the previously generated static image M(n−1), a second step for warping this video object on the basis of the estimated motion parameters, and a third step for blending the warped video object WV0(n) thus obtained with the previously generated static image M(n−1). According to the invention, an additional step for computing, for each picture element of the current video object, a weighting coefficient wWF(n)[x,y] correlated to the error between the warped video object and the static image M(n−1) is provided, and the blending formula now takes into account said weighting coefficients.