JPS55118146A - Software protecting system - Google Patents
Software protecting systemInfo
- Publication number
- JPS55118146A JPS55118146A JP2405379A JP2405379A JPS55118146A JP S55118146 A JPS55118146 A JP S55118146A JP 2405379 A JP2405379 A JP 2405379A JP 2405379 A JP2405379 A JP 2405379A JP S55118146 A JPS55118146 A JP S55118146A
- Authority
- JP
- Japan
- Prior art keywords
- code
- contents
- mem
- switch
- copy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Storage Device Security (AREA)
Abstract
PURPOSE:To make impossible the use of the PROM contents for other person even if he may copy the contents, by writing previously the contents of the memory device in a kind of the code from and then decoding the code into the original signal in the course the CPU fetches and uses the contents. CONSTITUTION:The raw data UP is converted into the code via code converter CCD and then written into memory device MEM. Then the same-type conversion is applied again to the converted code within MEM. As a result, the code is kept as before since no phase change is caused in both time at the area of switch ON, and the code is turned into the original form since the phase has inversion again at the area of switch OFF respectively. Thus the code as a whole is restored to the code before conversion to be turned to the raw data UP. Accordingly, the contents of MEM are never used by other person who does not know the switch state which is the code key even if he may copy the contents of MEM.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2405379A JPS55118146A (en) | 1979-03-03 | 1979-03-03 | Software protecting system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2405379A JPS55118146A (en) | 1979-03-03 | 1979-03-03 | Software protecting system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS55118146A true JPS55118146A (en) | 1980-09-10 |
Family
ID=12127710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2405379A Pending JPS55118146A (en) | 1979-03-03 | 1979-03-03 | Software protecting system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55118146A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5865470A (en) * | 1981-10-15 | 1983-04-19 | 日本電気株式会社 | Software protection circuit |
| JPS63276146A (en) * | 1987-05-06 | 1988-11-14 | Nec Corp | Semiconductor integrated circuit |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4855632A (en) * | 1971-11-12 | 1973-08-04 | ||
| JPS5189364A (en) * | 1975-02-03 | 1976-08-05 |
-
1979
- 1979-03-03 JP JP2405379A patent/JPS55118146A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4855632A (en) * | 1971-11-12 | 1973-08-04 | ||
| JPS5189364A (en) * | 1975-02-03 | 1976-08-05 |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5865470A (en) * | 1981-10-15 | 1983-04-19 | 日本電気株式会社 | Software protection circuit |
| JPS63276146A (en) * | 1987-05-06 | 1988-11-14 | Nec Corp | Semiconductor integrated circuit |
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