Method of protecting AT commands

• US 20090131033A1
• Filed: 11/20/2008
• Published: 05/21/2009
• Est. Priority Date: 11/20/2007
• Status: Active Grant

• Current Assignee: Spreadtrum Communications USA
• Original Assignee: Spreadtrum Communications USA
• Inventors: Gu, Xiangxin, Zhong, Rui, Miao, Hui, Lv, Ling
• Granted Patent: US 8,346,213 B2
• Time in Patent Office: Days
• US Class Current: 455/418
• CPC Class Codes: H04L 63/083 using passwords cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226
• CPC Class Codes: H04M 1/72409 by interfacing with external accessories hands-free H04M1/60
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 12/126 Anti-theft arrangements, e.g. protection against subscriber identity module [SIM] cloning
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

A method of protecting AT commands during the interaction between the AT command module of a mobile terminal and the serial communication unit of an external device, comprising the steps of: receiving AT command from the serial communication unit to the AT command module at an initial state; putting the AT command module into an ID verification mode, wherein the AT command module receives a username and password from the serial communication unit in turn, and verifies said received username and password; and putting the AT command module into an AT command processing state, when the ID verification is successful. Therefore, it'"'"'s impossible for an illegal user to take the control of the mobile terminal through AT command.

Claims

1. A method of protecting AT commands during the interaction between an AT command module of a mobile terminal and a serial communication unit of an external device, comprising the steps of:

(1) receiving said AT command from said serial communication unit to said AT command module;

(2) putting said AT command module into an ID verification mode, wherein said AT command module receives a username and password from said serial communication unit in turn, and verifies said received username and password;

(3) putting said AT command module into an AT command processing state, when said ID verification is successful.

2. The method of protecting AT commands, as recited in claim 1, further comprising a step of:

when the ID verification is unsuccessful, putting said AT command module into an initial state or a username input state.

3. The method of protecting AT commands, as recited in claim 1, wherein step (2) comprises steps of:

(a) sending information for prompting a user to input a username, and entering into a username input state;

(b) receiving a character string from said serial communication unit, remotely processing display of said character string according to a flag variable so as to display said inputted character string, and recording said character string as a username;

(c) sending information for prompting a user to input a password, and entering into a password input state; and

(d) receiving a character string from said serial communication unit, remotely processing display of said character string according to a flag variable so as to hide said inputted character string, and recording said character string as password.

4. The method of protecting AT commands, as recited in claim 3, wherein both step (b) and (d) comprise steps of:

reading said received character from a receiving buffer; and

determining whether said received character is password according to said flag variable;

when said received character is password, sending a hidden character to said serial communication unit;

when said received character is not password, sending said character back to said serial communication unit.

5. The method of protecting AT commands, as recited in claim 4, wherein said hidden character is “

*”

.

6. The method of protecting AT commands, as recited in claim 3, wherein both step (b) and (d) comprise steps of:

reading said received character from a receiving buffer in turn;

determining whether said received character is password according to said flag variable;

when said received character is password, determining whether said character is special character;

when said character is not special character, sending a hidden character to said serial communication unit, while when said character is special character, not sending a hidden character to said serial communication unit;

when said received character is not password, sending said character back to said serial communication unit.

7. The method of protecting AT commands, as recited in claim 3, wherein both step (b) and (d) comprise steps of:

reading said received character from a receiving buffer in turn;

determining whether said received character is password according to said flag variable;

when said received character is password, determining whether said character is special character;

when said character is not special character, sending a hidden character to said serial communication unit, while when said character is special character, setting the flag variable to a non-password state;

when the received character is not password, sending said character back to said serial communication unit.

8. The method of protecting AT commands, as recited in claim 6, wherein said special character includes a carriage return character and/or a line feed character.

9. The method of protecting AT commands, as recited in claim 7, wherein said special character includes a carriage return character and/or line feed character.

10. The method of protecting AT commands, as recited in claim 3, wherein both step (b) and (d) comprise steps of:

reading said received character from a receiving buffer in turn;

determining whether said received character is password according to said flag variable;

when said received character is password, sending a Backspace and a hidden character to said serial communication unit.

11. The method of protecting AT commands, as recited in claim 3, wherein step (b) further comprises a step of setting said flag variable to a password state.

12. The method of protecting AT commands, as recited in claim 3, wherein step (d) further comprises a step of setting said flag variable to a non-password state.

13. The method of protecting AT commands, as recited in claim 3, wherein in step (b) and (d), said AT command module receives said character string via an interrupt processing module, wherein step (2) is implemented by said interrupt processing module.

14. The method of protecting AT commands, as recited in claim 1, wherein said command comprises AT command.

15. The method of protecting AT commands, as recited in claim 1, wherein said step of verifying said received username and password comprises steps of:

comparing said received username to a username database to check whether said username exists;

when the username exists, verifying whether said received password is identical to a corresponding password;

wherein when said passwords are identical, ID verification is successful, and when said username does not exist or said passwords are not identical, ID verification is unsuccessful.

16. A method of protecting a mobile terminal from unauthorized AT commands, comprising a step of:

providing an ID verification function to said mobile terminal, which comprises a step of verifying an ID who is trying to control said mobile terminal from an external device via an AT command,

whereby when said ID is verified successful, said AT command is implemented to said mobile terminal, and when said ID is verified unsuccessful, said AT command is not implemented to said mobile terminal.

17. The method, as recited in claim 16, wherein said verifying ID step comprises steps of verifying a username and verifying a password, wherein Local Echo is unset, wherein when verifying said username, said mobile terminal sends inputted characters back to said external device, and when verifying said password, said mobile terminal sends hidden characters back to said external device.

18. The method, as recited in claim 16, wherein said verifying ID step comprises steps of verifying a username and verifying a password, wherein Local Echo is set, when said password being inputted, said mobile terminal sends a Backspace and a hidden character back to said external device when receiving each character, otherwise said mobile terminal does not send any character back to said external device.

19. The method of controlling a mobile terminal via AT commands, as recited in claim 17, wherein said mobile terminal has a flag variable for indicating whether said inputted character is username or password.

20. The method of controlling a mobile terminal via AT commands, as recited in claim 18, wherein said mobile terminal has a flag variable for indicating whether said inputted character is username or password.