Detecting rewriting of stored data, using codes based on password and the stored data
First Claim
1. A method for determining whether or not a rewrite of stored data has been made, comprising the steps of:
- (A) in storing newly prepared data;
inputting a password;
generating a first code by converting the input password and the newly prepared data in a predetermined procedure; and
storing the newly prepared data and the first code in correspondence thereto; and
(B) in reading out the stored data;
inputting the password;
generating a second code by converting the input password and the read out data in said predetermined procedure;
comparing the generated second code and said first code; and
determining that the rewrite of the newly prepared data has been made subsequent to storage in correspondence to the first code if the comparison result is unmatched.
1 Assignment
0 Petitions
Accused Products
Abstract
In storing data, a first code is generated by converting a password and some predetermined portion of the data itself (e.g., all of the data itself, or a time stamp) in a predetermined procedure. The first code is then stored in correspondence to the data. Thereafter, in reading the stored data, a second code is generated by converting the password and the same predetermined portion of the stored data, using the same predetermined procedure, and the resulting second code is compared with the first code stored in correspondence to the stored data. A determination is made that a rewrite has occurred, if the two codes do not match. Subsequent data processing may be controlled in accordance with the result of this determination.
50 Citations
27 Claims
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1. A method for determining whether or not a rewrite of stored data has been made, comprising the steps of:
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(A) in storing newly prepared data; inputting a password; generating a first code by converting the input password and the newly prepared data in a predetermined procedure; and storing the newly prepared data and the first code in correspondence thereto; and (B) in reading out the stored data; inputting the password; generating a second code by converting the input password and the read out data in said predetermined procedure; comparing the generated second code and said first code; and determining that the rewrite of the newly prepared data has been made subsequent to storage in correspondence to the first code if the comparison result is unmatched. - View Dependent Claims (2, 3, 4, 5)
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6. A method for determining whether or not a rewrite of stored data has been made, comprising the steps of:
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(A) in response to an instruction for storing newly prepared data; storing the newly prepared data with a present time appended; inputting a password; extracting said present time from the stored data; generating a first code by converting the input password and said extracted present time in a predetermined procedure; and storing said first code in correspondence to the newly prepared and stored data; and (B) in reading out the stored data; inputting the password; extracting said present time from the read out data; generating a second code by converting the input password and the read out data in said predetermined procedure; comparing the generated second code and said first code; and determining that the rewrite of the newly prepared data has been made subsequent to storage in correspondence to the first code if the comparison result is unmatched. - View Dependent Claims (7, 8, 9)
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10. A method for determining whether or not a rewrite of stored data has been made, comprising the steps of:
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(A) in response to an instruction for storing newly prepared data; storing the newly prepared data with a first present time appended; inputting a password; extracting said first present time from the stored data; generating a first code by converting the input password and said extracted first present time in a predetermined procedure; restoring said newly prepared data, accompanied by and distinguished from the generated first code and a second present time; and changing the second present time stored with the restored data to said first present time; and (B) in reading out the stored data; inputting the password; extracting said first present time from the read out data; generating a second code by converting the input password and said extracted first present time in said predetermined procedure; comparing the generated second code and said first code; and determining that the rewrite of the newly prepared data has been made subsequent to storage in correspondence to the first code if the comparison result is unmatched. - View Dependent Claims (11, 12)
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13. A method for determining whether or not a rewrite of stored data has been made, comprising the steps of:
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(A) in response to an instruction for storing newly prepared data; storing the newly prepared data with a first present time appended; inputting a password; inputting time information; generating a first code by converting the input password and the input time information in a predetermined procedure; restoring said newly prepared data, accompanied by and distinguished from the generated first code and a second present time; and changing the second present time stored with the restored data to said time information; and (B) in reading out the stored data; inputting the password; extracting said time information from the read out data; generating a second code by converting the input password and the extracted time information in said predetermined procedure; comparing the generated second code and said first code; and determining that the rewrite of the newly prepared data has been made subsequent to storage in correspondence to the first code if the comparison result is unmatched. - View Dependent Claims (14, 15)
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16. A method for determining whether or not a rewrite of stored data has been made, comprising the steps of:
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(A) in storing newly prepared data; determining a user; generating a first code by converting the information corresponding to the determined user and the newly prepared data in a predetermined procedure; and storing the newly prepared data and the first code in correspondence thereto; and (B) in reading out the stored data; determining the user; generating a second code by converting the information corresponding to the determined user and the read out data in said predetermined procedure; comparing the generated second code and said first code; and determining that the rewrite of the newly prepared data has been made subsequent to storage in correspondence to the first code if the comparison result is unmatched. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method for determining whether or not a rewrite of stored data has been made and processing the stored data in accordance with a result of such determination, comprising the steps of:
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(A) in storing newly prepared data; inputting a password; generating a first code by converting the input password and a predetermined portion of the newly prepared data in a predetermined procedure; and storing the newly prepared data and the first code in correspondence thereto; (B) in processing the stored data; inputting the password; generating a second code by reading out the stored data and converting the input password and said predetermined portion of the read out data in said predetermined procedure; comparing the generated second code and said first code; and processing the read out data if the comparison result is matched, and prohibiting the processing if the comparison result is unmatched. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification