US5481672A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detecting rewriting of stored data, using codes based on password and the stored data
Assignee: Canon Inc
•
Filing: 1992-02-27
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Granted: 1996-01-02
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Expires: 2012-02-27
Abstract
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.
Inventors
- 👤 Yasuhiro Okuno
- 👤 Tadashi Yamakawa
- 👤 Masaaki Nagashima
- 👤 Takayuki Sasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:37
CPC Classifications
G; G06; G06F; G06F21/00; G06F21/60; G06F21/62; G06F21/6209; G06F21/64; G06F2211/00; G06F2211/007; G06F2221/00; G06F2221/21; G06F2221/2151
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
125 words
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.
Claim 2
Independent Claim
125 words
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.
Claim 3
Dependent Claim
14 words
The method according to claim 1, wherein said newly prepared data comprises a text.
Claim 4
Dependent Claim
14 words
The method according to claim 1, wherein said newly prepared data comprises a program.
Claim 5
Dependent Claim
34 words
The method according to claim 1, wherein said data to be stored and said first code corresponding thereto are stored in a same file in such manner as to be distinguished from each other.
Claim 6
Dependent Claim
36 words
The method according to claim 1, wherein said first code is stored in a file having a file name generated by adding the file name for the data corresponding to said first code with an expander.
Claim 7
Independent Claim
158 words
A method for determining whether or not a rewrite of stored data has been made, comprising the steps of: (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.
Claim 8
Independent Claim
158 words
A method for determining whether or not a rewrite of stored data has been made, comprising the steps of: (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.
Claim 9
Dependent Claim
14 words
The method according to claim 6, wherein said newly prepared data comprises a text.
Claim 10
Dependent Claim
14 words
The method according to claim 6, wherein said newly prepared data comprises a program.
Claim 11
Dependent Claim
36 words
The method according to claim 6, wherein said first code is stored in a file having a file name generated by adding the file name for the data corresponding to said first code with an expander.
Claim 12
Independent Claim
184 words
A method for determining whether or not a rewrite of stored data has been made, comprising the steps of: (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.
Claim 13
Independent Claim
184 words
A method for determining whether or not a rewrite of stored data has been made, comprising the steps of: (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.
Claim 14
Dependent Claim
14 words
The method according to claim 10, wherein said newly prepared data comprises a text.
Claim 15
Dependent Claim
14 words
The method according to claim 10, wherein said newly prepared data comprises a program.
Claim 16
Independent Claim
174 words
A method for determining whether or not a rewrite of stored data has been made, comprising the steps of: (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.
Claim 17
Independent Claim
174 words
A method for determining whether or not a rewrite of stored data has been made, comprising the steps of: (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.
Claim 18
Dependent Claim
14 words
The method according to claim 13, wherein said newly prepared data comprises a text.
Claim 19
Dependent Claim
14 words
The method according to claim 13, wherein said newly prepared data comprises a program.
Claim 20
Independent Claim
133 words
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: 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.
Claim 21
Independent Claim
133 words
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: 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.
Claim 22
Dependent Claim
14 words
The method according to claim 16, wherein said newly prepared data comprises a text.
Claim 23
Dependent Claim
14 words
The method according to claim 16 wherein said newly prepared data comprises a program.
Claim 24
Dependent Claim
36 words
The method according to claim 16, wherein said first code is stored in a file having a file name generated by adding the file name for the data corresponding to said first code with an expander.
Claim 25
Dependent Claim
17 words
The method according to claim 16, wherein the information corresponding to said user comprises a user name.
Claim 26
Dependent Claim
23 words
The method according to claim 16, wherein the information corresponding to said user comprises a log-in directory correspondent to a plurality of users.
Claim 27
Independent Claim
144 words
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: (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.
Claim 28
Independent Claim
144 words
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: (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.
Claim 29
Dependent Claim
21 words
The method according to claim 22, wherein said predetermined portion of the newly prepared data is the newly prepared data itself.
Claim 30
Dependent Claim
15 words
The method according to claim 22, wherein said password comprises information corresponding to the user.
Claim 31
Dependent Claim
14 words
The method according to claim 22, wherein said newly prepared data comprises a text.
Claim 32
Dependent Claim
14 words
The method according to claim 22, wherein said newly prepared data comprises a program.
Claim 33
Dependent Claim
38 words
The method according to claim 22, further comprising the step of second processing the read out data when the comparison result is unmatched, wherein the second processing is different from the processing when the comparison result is matched.
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