Patent ID: 7975145
Filing Date: 2011-07-05
Classification: H04L

Abstract:
1. An apparatus for update of a time stamp, the apparatus being able to certify certification target data on the basis of time stamp data transmitted from an apparatus for time stamp authority, the apparatus comprising: an evidence data storage unit configured to relate the certification target data to the time stamp data and to save the related certification target data and time stamp data; a time stamp obtaining unit configured to transmit hash value calculated from seal target data including the time stamp data that has already been related to the certification target data to the apparatus for time stamp authority according to a certain prescribed timing, to obtain time stamp data to the seal target data from the apparatus for time stamp authority, to relate the obtained time stamp data to the certification target data, and to store the related time stamp data and the certification target data in the evidence data storage unit; a verification table data storage unit configured to store verification table data including respective validity periods of a set of time stamps corresponding to the time stamp data obtained by the time stamp obtaining unit; and a time stamp verification unit configured to output a period in which the validity periods in the verification table data are continuous from a time of verification as a period when the certification target data can be certified.