System for computer software protection

• US 5,666,411 A
• Filed: 01/13/1994
• Issued: 09/09/1997
• Est. Priority Date: 01/13/1994
• Status: Expired due to Term

• Current Assignee: Intarsia Software LLC (Intellectual Ventures LLC)
• Original Assignee: Johnnie C. Mccarty
• Inventors: McCarty, Johnnie C.
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/180,602
• Time in Patent Office: 1,335 Days
• Field of Search: 380/3, 380/25, 380/4
• US Class Current: 705/51
• CPC Class Codes: G06F 21/109 by using specially-adapted hardware at the client
• CPC Class Codes: G06F 21/123 by using dedicated hardware, e.g. dongles, smart cards, cryptographic processors, global positioning systems [GPS] devices
• CPC Class Codes: G06F 21/72 in cryptographic circuits
• CPC Class Codes: G06F 2207/7219 Countermeasures against side channel or fault attacks
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06F 9/3879 for non-native instruction execution, e.g. executing a command; for Java instruction set
• CPC Class Codes: H04L 9/0822 using key encryption key

Abstract

This system protects proprietary software from disclosure and unauthorized use, enforces license limits on number of users of the software, and prevents corruption of protected software by computer viruses. Software protected under this system may execute only on computer systems which incorporate a microprocessor capable of deciphering enciphered instructions in real time. Program files are first enciphered under control of a distribution cipher key. Prior to first use of software, program files must be customized on the user computer system. This customization procedure re-enciphers the programs, so that they are enciphered under a second cipher key. Customized programs may not execute on a computer system other than one constructed with a processor chip which incorporates a crypto microprocessor. The crypto microprocessor is capable of performing this re-encipherment, and of executing both enciphered and unenciphered programs. The customization program runs on user'"'"'s computer system and normally accesses a remote Exchange database system by means of a modem to accomplish its task. Variations of customization process provide for storage of enciphered software on either a single system, a network server, or a site license repository system.

Claims

1. A system for restricting the execution of a computer program comprising:

means for re-enciphering the computer program from a first cipher forms stored on a distribution media to a second cipher form during initial installation of said program onto a predetermined storage means of an authorized computer system

wherein said second cipher form is unique to the authorized computer system;

means for loading the computer program in said second cipher form onto the computer system; and

means for executing the computer program on the authorized computer system.

2. The system of claim 1 wherein said means for re-enciphering a computer program during installation comprises:

means for sending information identifying said computer program and said authorized computer system to a remote exchange database system, said computer system having a system cipher key, wherein said remote database system returns a program cipher key unique to said computer program, and wherein said program cipher key is itself enciphered under said system cipher key;

means for receiving said enciphered program cipher key from said remote database system; and

means for translating said computer program into a second cipher form unique to the authorized computer system wherein said translating means is a function of said program cipher key and said system cipher key.

3. The system of claim 1 where said execution means comprises:

a microprocessor including means for generating an execution cipher key, said generating means having said system cipher key as an input term and further including means for combining said computer instructions with said execution cipher key under a deciphering function, such that unenciphered and executable computer instructions are accessible to the microprocessor but are not externally accessible.

4. The system of claim 2, wherein:

said executing means comprises;

a microprocessor including means for generating an execution cipher key.

5. The system of claim 1 wherein said loading means comprises:

means for reading successive portions of said program in said second ciphered form into said computer'"'"'s main memory; and

means for translating said successive portions wherein said translating means deciphers then enciphers said successive portions in one indivisible operation.

6. A system for restricting the execution of a computer program comprising:

means for re-enciphering a computer program from a first cipher form stored on a distribution media to a second cipher form during initial installation of said program onto predetermined storage means of a file server wherein said second cipher form is executable only on authorized computer systems attached to said server;

means for loading said program from said file server onto the authorized computer systems; and

means for executing said program on the authorized computer systems.

7. The system of claim 6 wherein said loading means comprises:

means for reading successive portions of said program into the main memory of the authorized computer systems; and

means for translating said successive portions wherein said translating means deciphers then enciphers said successive portions in one indivisible operation.

8. A method for restricting the execution of a computer program comprising the steps of:

enciphering a computer program in a first cipher form stored on a distribution media;

initially installing said program in a computer system having a crypto microprocessor by perfoming the steps of;

obtaining data from a remote exchange system;

re-enciphering said program from said first cipher form to a second cipher form by translating said program with said crypto microprocessor an said data; and

storing said program onto storage a predetermined means of the computer system in said second form; and

transferring said program from the predetermined storage means to the computer system, deciphering said program from said second cipher form to a deciphered form with said crypto microprocessor, and executing said program in said deciphered form.

9. The method according to claim 8 wherein said crypto microprocessor deciphers and enciphers the program in a single indivisible operation.

10. The method according to claim 9 wherein:

said computer system has a system cipher key;

said remote exchange system only releases said data upon receipt of said system cipher key;

said data includes a program cipher key; and

said re-enciphering from said first cipher form to said second cipher form is performed by a translation function utilizing said system cipher key and said program cipher key.

11. The method according to claim 9 wherein the computer system executes said program in successive portions wherein said successive portions are deciphered, executed and then enciphered in one indivisible operation.

12. The method according to claim 11 wherein said successive portions are re-enciphered from said second cipher form to a third cipher form, then deciphered and executed.