Firmware encrypting and decrypting method and an apparatus using the same

• US 20050154912A1
• Filed: 01/07/2005
• Published: 07/14/2005
• Est. Priority Date: 01/09/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jong-gyou, Kim, In-koo
• Granted Patent: US 7,929,692 B2
• Time in Patent Office: Days
• US Class Current: 726/26
• CPC Class Codes: G06F 21/72 in cryptographic circuits

Abstract

A method of encrypting and decrypting a firmware used in electronic devices and an apparatus using the same. The firmware encryption method includes, receiving a predetermined special key data; generating an encryption key data from the predetermined special key data using a predetermined random number; generating an encryption data corresponding to firmware address information to be stored to a memory based on the encryption key data; and generating an encrypted firmware data by performing an XOR operation on the encryption data and firmware data to be stored in the firmware address.

Claims

1. A firmware encryption method, comprising:

receiving a predetermined special key data;

generating an encryption key data from the predetermined special key data using a predetermined random number;

generating an encryption data corresponding to firmware address information to be stored in a memory based on the encryption key data; and

generating an encrypted firmware data by performing an XOR operation on the encryption data and firmware data to store the encrypted firmware data based on the firmware address information.

2. The method according to claim 1, wherein the encryption key data is composed of N bytes of the firmware data, and N is a predetermined integer.

3. The method according to claim 1, wherein the encryption data is generated by selecting one byte from N bytes of the encryption key data according to values of predetermined bits of the firmware address information.

4. A firmware decryption method, comprising:

reading a predetermined special key data stored in a memory upon determining that a condition to operate the firmware is satisfied;

generating an encryption key data based on the predetermined special key data;

generating an encryption data corresponding to firmware address information to read an encrypted firmware data from the memory; and

generating an decrypted firmware data by performing an XOR operation on the encryption data and the firmware data read based on the firmware address information to decrypt the encrypted firmware data.

5. The method according to claim 4, wherein the encryption key data is composed of N bytes of the firmware data, and N is a predetermined integer.

6. The method according to claim 4, wherein the encryption data is generated by selecting a byte from N bytes of the encryption key data according to values of predetermined bits of the firmware address information.

7. A firmware encryption apparatus, comprising:

an encryption key generator generating encryption key data from a predetermined input special key data using a predetermined random number; and

a firmware encryption processing unit generating an encryption data corresponding to firmware address information based on the encryption key data and generating an encrypted firmware data by performing an XOR operation on the encryption data and firmware data to store the encrypted firmware data based on the firmware address information.

8. The apparatus according to claim 7, wherein the encryption key data is composed of N bytes of the firmware data, and N is a predetermined integer.

9. The apparatus according to claim 7, wherein the encryption data is generated by selecting one byte from N bytes of the encryption key data according to values of predetermined bits of the firmware address information.

13. The apparatus according to claim 7, wherein the predetermined special key data received by the encryption key generator is transmitted from an external device.

14. The apparatus according to claim 13, wherein the encryption key generator receives a 256 bit special key data as the predetermined special key data, and generates a 32 bit data as the encryption key data.

15. The apparatus according to claim 14, wherein the 32 bit data generated as the encryption key data includes an 8 bit data as the firmware data and a 16 bit data as the firmware address information.

16. The apparatus according to claim 15, wherein the encryption data generated by firmware encryption processing unit is based on lowest 2 bits of the. firmware address.

17. The apparatus according to claim 7, further comprising:

a ROM writer to write the encrypted firmware data to a memory.

10. A firmware decryption apparatus comprising:

a memory storing an encrypted firmware and a predetermined special key data;

a microprocessor reading the predetermined special key data from the memory upon determining that a condition to operate the firmware is satisfied, generating firmware address information to read the encrypted firmware from the memory and a read control signal and executing a program included in the encrypted firmware;

an encryption key generator generating encryption key data from the predetermined special key data using a predetermined random number; and

a firmware decryption processing unit generating an encryption data corresponding to the firmware address information using the encryption key data and generating decrypted firmware data by performing an XOR operation on the encryption data and the encrypted firmware data read based on the firmware address information.

11. The apparatus according to claim 10, wherein the encryption key data is composed of N bytes of the firmware data, and N is a predetermined integer.

12. The apparatus according to claim 10, wherein the encryption data is generated by selecting a byte from N bytes of the encryption key data according to values of predetermined bits of the firmware address information.

18. A method to encrypt firmware data of an electronic device, comprising:

generating an encryption data corresponding to an address in a memory based on an encryption key data generated from a predetermined special key data using a random number; and

encrypting the firmware data by performing an XOR operation on the encryption data and the firmware data, and storing the encrypted firmware data to the address in memory.

19. The method according to claim 18, wherein the encryption data is generated by selecting one byte from N bytes of the encryption key data according to values of predetermined bits of the address in the memory.

20. A method to decrypt an encrypted firmware data of an electronic device, comprising:

generating an encryption key data using a predetermined special key data stored in a memory upon determining that a condition to use the encrypted firmware data is satisfied;

generating an encryption data corresponding to an address in the memory to read the encrypted firmware data; and

decrypting the encrypted firmware data by performing an XOR operation on the generated encryption data and the encrypted firmware data read from the memory.

21. The method according to claim 21, wherein the encryption key data is composed of predetermined bytes of the firmware data.

22. A computer readable medium recorded with a program to execute a firmware encryption operation, the operation comprising:

generating an encryption data corresponding to an address in a memory based on an encryption key data generated from a predetermined special key data using a random number; and

encrypting the firmware data by performing an XOR operation on the encryption data and the firmware data, and storing the encrypted firmware data to the address in memory.

23. A computer readable medium recorded with a program to execute a firmware decryption operation, the operation comprising:

generating an encryption key data using a predetermined special key data stored in a memory upon determining that a condition to use the encrypted firmware data is satisfied;

generating an encryption data corresponding to an address in the memory to read the encrypted firmware data; and

decrypting the encrypted firmware data by performing an XOR operation on the generated encryption data and the encrypted firmware data read from the memory.