Cartridge-controlled system whose use is limited to authorized cartridges

• US 4,670,857 A
• Filed: 10/26/1981
• Issued: 06/02/1987
• Est. Priority Date: 10/26/1981
• Status: Expired due to Term

• Current Assignee: Michael I. Rackman
• Original Assignee: Michael I. Rackman
• Inventors: Rackman, Michael I.
• Primary Examiner(s): Chan, Eddie P.
• Application Number:
  US06/315,204
• Time in Patent Office: 2,045 Days
• Field of Search: 364/200, 364/900, 178/22.01, 178/22.02, 178/22.03, 178/22.04, 178/22.05, 178/22.06, 178/22.07, 178/22.08, 178/22.09, 178/22.10, 178/22.11, 178/22.12 , 178/22.13, 178/22.14, 178/22.15, 178/22.16, 178/22.17, 178/22.18, 178/22.19, 178/22.20, 178/22.21
• US Class Current: 705/51
• CPC Class Codes: G06F 21/12 Protecting executable software
• CPC Class Codes: G06F 2221/2109 Game systems

Abstract

A cartridge-controlled system whose use is limited to authorized cartridges. Blocks of instructions of a program designed to run on the machine are encrypted by the machine manufacturer using the private key of a public-key cryptosystem pair. The machine, during an initialization step following the insertion of a new cartridge, decrypts information strings stored in the cartridge through use of the associated public key, and stores the resulting decrypted instructions in random access memory. The machine microprocessor then accesses the instructions in the random access memory. Although the public key may be widely known, as long as the private key is kept secret, there is no way for an unauthorized software/cartridge supplier to encrypt a program such that following decryption in the machine there will result an intelligible sequence of instructions.

Claims

1. A plurality of mass-produced identical systems each comprising data processing means for generating memory-accessing address signals and for executing memory-furnished instructions;

and means for interfacing said data processing means with an insertable cartridge having a read-only-memory contained therein;

characterized by a read-write memory;

said data processing means further controlling generation of memory-accessing address signals to allow accessing of blocks of encrypted instructions from the read-only-memory of an inserted cartridge, decryption of the blocks of encrypted instructions thus accessed, and generation of memory-accessing address signals to allow storage of the decrypted blocks of instructions in said read-write memory, and thereafter executing instructions furnished by said read-write memory in response to generated memory-accessing address signals;

said blocks of instructions being stored in encrypted form in said read-only-memory in accordance with a private key which is associated with a public key of a public-key cryptosystem pair, and said data processing means controlling the decryption of said blocks of encrypted instructions in accordance with said public key;

each of said identical systems controlling said decryption and thereafter execution of instructions furnished by its read-write memory in the identical manner responsive to insertion of the same cartridge.

2. A plurality of mass-produced identical systems in accordance with claim 1 wherein said instructions are encrypted and decrypted in blocks long enough to prevent practical discovery of said private key.

3. A method for allowing the manufacturer of a plurality of mass-produced identical ROM-cartridge controlled machines to prevent unauthorized persons from manufacturing original ROM cartridges capable of controlling machine operations, each machine including a read-write memory for storing the instructions which control the machine operation, comprising the steps of (1) controlling each machine (a) to read from a ROM cartriage blocks of encrypted instructions, to decrypt the blocks of instructions thus read, and to store the decrypted blocks of instructions in the read-write memory, and (b) thereafter to execute instructions accessed from the read-write memory, and (2) encrypting blocks of the actual instructions to be executed by any machine and storing the encrypted blocks of instructions in a ROM cartridge to be used to control any machine operation, the encryption and decryption steps being carried out respectively in accordance with the private and public keys of a public-key cryptosystem pair;

each of said identical machines controlling said decryption and thereafter execution of instructions furnished by its read-write memory in the identical manner responsive to insertion of the same ROM cartridge.

4. A method in accordance with claim 3 wherein said instructions are encrypted and decrypted in blocks long enough to prevent practical discovery of said private key.

5. A plurality of mass-produced identical systems each comprising data processing means for generating memory-accessing address signals and for executing memory-furnished instructions;

and means for interfacing said data processing means with an insertable storage medium having information stored therein;

characterized by a read-write memory;

said data processing means further controlling generation of memory-accessing address signals to allow accessing of information in the form of blocks of encrypted instructions from an inserted storage medium, decryption of the blocks of encrypted instructions thus accessed, and generation of memory-accessing address signals to allow storage of the decrypted blocks of instructions in said read-write memory, and thereafter executing instructions furnished by said read-write memory in response to generated memory-accessing address signals;

said blocks of instructions being stored in encrypted form in said storage medium in accordance with a private key which is associated with a public key of a public-key cryptosystem pair, and said data processing means controlling the decryption of said blocks of encrypted instructions in accordance with said public key;

each of said identical systems controlling said decryption and thereafter execution of instructions furnished by its read-write memory in the identical manner responsive to insertion of the same storage medium.

6. A plurality of mass-produced identical systems in accordance with claim 5 wherein said instructions are encrypted and decrypted in blocks long enough to prevent practical discovery of said private key.

7. A method for allowing the manufacturer of a plurality of mass-produced identical machines controlled by instructions contained in an insertable storage medium to prevent unauthorized persons from manufacturing original storage media capable of controlling machine operations, each machine including a read-write memory for storing instructions which control the machine operation, comprising the steps of (1) controlling each machine (a) to read from an inserted storage medium blocks of encrypted instructions, to decrypt the blocks of instructions thus read, and to store the decrypted blocks of instructions in the read-write memory, and (b) thereafter to execute instructions accessed from the read-write memory, and (2) encrypting blocks of the actual instructions to be executed by any machine and storing the encrypted blocks of instructions in a storage medium to be used to control any machine operation, the encryption and decryption steps being carried out respectively in accordance with the private and public keys of a public-key cryptosystem pair;

each of said identical machines controlling said decryption and thereafter execution of instructions furnished by its read-write memory in the identical manner responsive to insertion of the same storage medium.

8. A method in accordance with claim 7 wherein said instructions are encrypted and decrypted in blocks long enough to prevent practical discovery of said private key.