Data access method against cryptograph attack

1. A data access method used with a data storage apparatus having at least one NAND flash memory, the method comprising the steps of:

creating a predetermined password;

generating a first encryption key based on the predetermined password;

encrypting data with an encryption unit of the data storage apparatus based on the first encryption key;

prompting for the predetermined password upon receipt of an access request;

decoding a header of the NAND flash memory based on a user-entered password;

examining the decoded header to determine whether a mapping between the user entered password and the first encryption key is defined; and

decrypting and outputting the data by a decryption key when the mapping between the user-entered password and the first encryption key is defined.

2. The data access method according to claim 1 , wherein the decoding step comprises step of translating the user-entered password into a second encryption key for decoding the header.

3. The data access method according to claim 1 , further comprising step of prompting for the predetermined password when the mapping between the user-entered password and the first encryption key is not defined.

4. The data access method according to claim 1 , wherein the header is in a first logical block.

5. The data access method according to claim 1 , wherein the decryption key is the same as the first encryption key.

6. The data access method according to claim 1 , wherein the data are encrypted according to Advanced Encryption Standard (AES), Data Encryption Standard (DES), Triple-DES, and Rivest-Shamir-Adleman (RSA).

7. The data access method according to claim 1 , wherein the data storage apparatus comprises a Universal Serial Bus (USB) Penprive, a Smart Digital (SD) card, a MultiMedia Card (MMC), a Compact Flash (CF) card, and a USB flash drive.

8. The data access method according to claim 2 , wherein the first and second encryption keys translated from the passwords can be accomplished by software or hardware.

9. The data access method according to claim 2 , wherein the first, second encryption keys, and the decryption key can be revised by a data read/write device.

10. The data access method according to claim 2 , wherein the first, second encryption keys, and the decryption key each has a length of 64 bits, 128 bits, 192 bits, or 256 bits.

11. A data access method used with a data storage apparatus having at least one NAND flash memory, the method comprising the steps of:

prompting for a predetermined password upon receipt of an access request for data;

translating a user-entered password into an encryption key;

decoding a header of the NAND flash memory based on the encryption key;

examining the decoded header to determine whether a mapping between the user entered password and a predetermined encryption key is defined; and

decrypting the data with an decryption unit of the data storage apparatus utilizing a decryption key and outputting the data when the mapping between the user-entered password and the predetermined encryption key is defined.

12. The data access method according to claim 11 , wherein the predetermined encryption key is translated in accordance with the predetermined password.

13. The data access method according to claim 11 , further comprising step of prompting for the predetermined password when the mapping between the user-entered password and the predetermined encryption key is not defined.

14. The data access method according to claim 11 , wherein the encryption key and the predetermined encryption key translated from the passwords can be accomplished by software or hardware.

15. The data access method according to claim 11 , wherein the header is in a first logical block.

16. The data access method according to claim 11 , wherein the encryption key, the predetermined encryption key, and the decryption key can be revised by a data read/write device.

17. The data access method according to claim 11 , wherein the decryption key is the same as the predetermined encryption key.

18. The data access method according to claim 11 , wherein the encryption key, the predetermined encryption key and the decryption key each has a length of 64 bits, 128 bits, 192 bits, or 256 bits.

19. The data access method according to claim 11 , wherein the data are encrypted according to Advanced Encryption Standard (AES), Data Encryption Standard (DES), Triple-DES, and Rivest-Shamir-Adleman (RSA).

20. The data access method according to claim 11 , wherein the data storage apparatus comprises a USB Penprive, a SD card, a MMC, a CF card, and a USB flash drive.