Apparatus and program for update of time stamp

• US 20070106912A1
• Filed: 10/26/2006
• Published: 05/10/2007
• Est. Priority Date: 11/04/2005
• Status: Active Grant

• Current Assignee: Toshiba Solutions Corporation (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Solutions Corporation (Toshiba Corporation)
• Inventors: Tanaka, Tomonari
• Granted Patent: US 7,975,145 B2
• Time in Patent Office: Days
• US Class Current: 713/193
• CPC Class Codes: H04L 9/3268 using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]
• CPC Class Codes: H04L 9/3297 involving time stamps, e.g. generation of time stamps

Abstract

A time stamp updating apparatus includes: a time stamp obtaining unit configured to transmit hash value calculated from certification target data to an apparatus for time stamp authority when certification target data is input, to receive time stamp data from the apparatus for time stamp authority, to relate the received time stamp data to certification target data, and stored them in an evidence data storage unit; and a time stamp verification unit configured to calculate logical OR of a validity period of the time stamp data related to certification target data, and to output a period that can go back from time of verification as a period when the certification target data can be certified.

Claims

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 receive 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; and

a time stamp verification unit configured to calculate logical OR of a validity period of the time stamp data related to the certification target data, and to output a period that can go back from time of verification as a period when the certification target data can be certified.

2. The apparatus of claim 1, wherein the seal target data is latest time stamp data among the time stamp data that have already been related to the certification target data.

3. The apparatus of claim 1, wherein the seal target data includes the time stamp data and the certification target data, wherein the time stamp data have already been provided for the certification target data.

4. The apparatus of claim 1, wherein the seal target data includes hash value calculated from original time stamp data provided for new certification target data of a predetermined generation and overwriting time stamp data provided for each of generation on the basis of the original time stamp data of a previous generation from the predetermined generation.

5. The apparatus of claim 3, wherein the time stamp verification unit

extracts time stamp data generated on the basis of the certification target data;

registers a validity period of original time stamp data in a validity period verification table when succeeding in the verification of the aforementioned original time stamp data provided for the certification target data,

registers a validity period of the overwriting time stamp data in the validity period verification table when succeeding in the verification of the aforementioned overwriting time stamp data of a next generation of a target generation to which the original time stamp data provided for the certification target data belongs,

repeats processing that registers a validity period of the overwriting time stamp data of the next generation of the target generation in the validity period verification table when succeeding in the verification of the overwriting time stamp data of the next generation of incremented target generation until the next generation of the target generation becomes the latest generation while incrementing the target generation, and

calculates logical OR of the validity period of the registered time stamp data registered in the validity period verification table, and outputs a period that can go back from the time of the verification as a period when the certification target data can be certified.

6. The apparatus of claim 1 further comprising a monitoring unit for key updating configured to detect a key in the apparatus for time stamp authority being updated, wherein

the time stamp obtaining unit transmits hash value calculated from seal target data including time stamp data that has already been related to the certification target data to the apparatus for time stamp authority according to timing where the key is detected being updated by the monitoring unit for key updating, receives the time stamp data from the apparatus for time stamp authority, and stores the received time stamp data in the evidence data storage unit.

7. A computer executable program for update of a time stamp, the computer executable program being able to certify certification target data on the basis of time stamp data transmitted from an apparatus for time stamp authority, the computer executable program comprising:

in an evidence data storage unit, relating the certification target data to the time stamp data and saving the related certification target data and time stamp data;

in a time stamp obtaining unit, transmitting 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, receiving time stamp data to the seal target data from the apparatus for time stamp authority, relating the obtained time stamp data to the certification target data, and storing the related time stamp data and the certification target data in the evidence data storage unit; and

in a time stamp verification unit, calculating logical OR of a validity period of the time stamp data related to the certification target data, and outputting a period that can go back from time of verification as a period when the certification target data can be certified.

8. The computer executable program of claim 7, wherein the seal target data is latest time stamp data among the time stamp data that have already been related to the certification target data.

9. The computer executable program of claim 7, wherein the seal target data includes the time stamp data that have already been provided for the certification target data and the certification target data.

10. The computer executable program of claim 7, wherein the seal target data includes hash value calculated from original time stamp data provided for new certification target data of a predetermined generation and overwriting time stamp data provided for each generation on the basis of the original time stamp data of a previous generation from the predetermined generation.

11. The computer executable program of claim 9, wherein in the time stamp verification unit,

time stamp data generated on the basis of the certification target data is extracted,

a validity period of original time stamp data is registered in a validity period verification table when succeeding in the verification of the aforementioned original time stamp data provided for the certification target data,

a validity period of the overwriting time stamp data is registered in the validity period verification table when succeeding in the verification of the aforementioned overwriting time stamp data of a next generation of a target generation to which the original time stamp data provided for the certification target data belongs,

processing that registers a validity period of the overwriting time stamp data of the next generation of the target generation in the validity period verification table is repeated when succeeding in the verification of the overwriting time stamp data of the next generation of incremented target generation until the next generation of the target generation becomes the latest generation while incrementing the target generation, and

logical OR of the validity period of the registered time stamp data registered in the validity period verification table is calculated, and a period that can go back from the time of the verification is output as a period when the certification target data can be certified.

12. The computer executable program of claim 7 further comprising, in a monitoring unit for key updating, detecting a key in the apparatus for time stamp authority being updated, and the computer executable program wherein

in the time stamp obtaining unit, hash value calculated from seal target data including time stamp data that has already been related to the certification target data is transmitted to the apparatus for time stamp authority according to timing where the key is detected being updated by the monitoring unit for key updating, the time stamp data is received from the apparatus for time stamp authority, and the received time stamp data is stored in the evidence data storage unit.