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EP0114522A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

ROM protection device

Assignee: Synertek Inc
•
Filing: 1983-12-22
•
Granted: —
•
Expires: 2003-12-22
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Abstract

Abstract A ROM module 14 is coupled to a processor 10, which uses program and/or data information stored in module 14. To protect the information from unauthorized copying, a key memory 11 in the processor 10 and a key memory 15 in the module 14 are arranged to store identical keys. Two encryption and/or decryption units 12 and 16, in processor 10 and module 16 as shown, encode and decode information passing between the processor 10 and the module 14. The encryption and decryption may be applied to either the addresses sent to the module 14, the data coming from it, or preferably both. The key register 15 may be repeatedly writeable, in which case the initial data transference between the processor and the module must be the key transmission, without encryption. Alternatively, the key memory 15 may be once writeable, so that the module is useable only with a processor which is preset with the key.

Inventors

  • 👤 James T. Koo

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-26 03:37
CPC Classifications
G; G06; G06F; G06F21/00; G06F21/70; G06F21/78; G06F21/79; G06F12/00; G06F12/14; G06F12/1408

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 46 words
1 . A module (14) for storing information and including a ROM (17), characterized by a key memory (15) and an encryption and/or decryption unit (16) which encrypts and/or decrypts information passing to and from the ROM in dependence on the contents of the key memory.
Claim 2
Dependent Claim 46 words
1 . A module (14) for storing information and including a ROM (17), characterized by a key memory (15) and an encryption and/or decryption unit (16) which encrypts and/or decrypts information passing to and from the ROM in dependence on the contents of the key memory.
Claim 3
Dependent Claim 17 words
A module according to Claim 1, characterized in that the key memory is a repeatedly writeable memory.
Claim 4
Dependent Claim 17 words
A module according to Claim 1, characterized in that the key memory is a once programmable memory.
Claim 5
Dependent Claim 23 words
A module according to any previous Claim, characterized in that the encryption and/or decryption unit comprises a set of Exclusive-OR gates (Figure 2)..
Claim 6
Dependent Claim 45 words
A memory according to Claim 4, characterized by switching means (34, 35) effective to couple the set of Exclusive-OR gates in the bus to the ROM when information passes to the ROM and in the bus from the ROM when information passes from the ROM.
Claim 7
Dependent Claim 46 words
A data processing system (10) for receiving a module according to any previous Claim, characterized by a key (11) and an encryption and/or decryption unit (12) which encrypts and/or decrypts information passing to and from the module in dependence on the contents of the key memory.

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