DEVICE AND METHOD FOR MAKING AUTHENTICATABLE DIGITAL RECORD

    公开(公告)号:JPH10106149A

    公开(公告)日:1998-04-24

    申请号:JP19345597

    申请日:1997-07-18

    Applicant: IBM

    Abstract: PROBLEM TO BE SOLVED: To prevent forgery of a record by periodically receiving a challenge from an approval source by a camera or a recording device. SOLUTION: Unpredictable digital signal and challenge are periodically and simultaneously communicated by the approval source 10. These are received and stored by an approval challenge repository 20. Simultaneously, these are also received by a video camera assembly 25, and video signal 50 is digitalized by a digitalizer 55 and is stored in a large capacity storage medium 60 for the purpose of retrieval later on. Then, this output of the means 55 is also supplied to a digester 65, and is digested by using a hash function, so as to be transmitted via a transmitting means 70 to an approval digest repository 75, where the digested digital signal is stored together with its receiving time and other identification information. Consequently, when a length between recording time and certification time is shortened, a forger is asked for a large amt. of information, and hence simulation of recording the challenge in real time cannot be performed in such a brief time.

    5.
    发明专利
    未知

    公开(公告)号:DE69002845D1

    公开(公告)日:1993-09-30

    申请号:DE69002845

    申请日:1990-02-08

    Applicant: IBM

    Abstract: Quantum mechanical effect devices (1) incorporate means (3, 4) for interrupting the two-dimensional carrier gas of a modulation doped structure (2) to produce periodic potential variations which provide superlattice-like effects on current flowing nearby. The modulation doped structures (2) incorporate specialized structures (3, 4) displaced from a current path which simultaneously confine the two-dimensional carrier gas into a quasi-one-dimensional carrier gas and subject the thus confined carrier gas and current flowing therein to superlattice-like effects by inducing periodic potential variations along the current path. The induced variations are produced by etching corrugations in the device edges or by forming them in biasing gates (25).

    7.
    发明专利
    未知

    公开(公告)号:DE69002845T2

    公开(公告)日:1994-03-17

    申请号:DE69002845

    申请日:1990-02-08

    Applicant: IBM

    Abstract: Quantum mechanical effect devices (1) incorporate means (3, 4) for interrupting the two-dimensional carrier gas of a modulation doped structure (2) to produce periodic potential variations which provide superlattice-like effects on current flowing nearby. The modulation doped structures (2) incorporate specialized structures (3, 4) displaced from a current path which simultaneously confine the two-dimensional carrier gas into a quasi-one-dimensional carrier gas and subject the thus confined carrier gas and current flowing therein to superlattice-like effects by inducing periodic potential variations along the current path. The induced variations are produced by etching corrugations in the device edges or by forming them in biasing gates (25).

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