Top | Introduction | Members | Activities | Call for Paper | Link | Japanese

    "Visual Secret Sharing Scheme with Optional Access Structure at Efficient Number of Subpixels"

    In 1994, Naor and Shamir proposed Visual Secret Sharing Scheme(VSSS) as the application of SSS. This scheme encrypts a secret image into plural shadow images called share images and distributes them to participants. In the set of participants, the qualified set can restore the secret image, but the other set can not obtain any information about the secret.

    We expect VSSS to be able to deal with various kind of access structures, because there are the difference among the privileges authorized to participants in real society. (k, n) access structures do not have much practical use because the privileges of all participants in this access structure are equivarent.

    One of the important evaluation criteria for VSSS is the number of subpixels m.The less the value of m is, the smaller the decline in quality of the restored image against the original secret image is. But m tends to increase in proportion to the number of the participants.

    In this thesis, extending the method of [ABSS96], we propose a VSSS which can deal with general access structures with efficient number of subpixels. Moreover, applying this proposed scheme, we present the method by which we can restore the plural kind of secret images at the combination of participants.

    [ back ]