Password encryption for controlling access to electronic control units
A method of providing access to a password-protected electronic control unit (ECU) using encryption includes generating a cryptographic key for the ECU using a master password, a serial number of the ECU, and a password-based key derivation function; converting the generated cryptographic key into an ECU password; and accessing data from the ECU using the ECU password.
1. A method of providing access to a password-protected electronic control unit (ECU) using encryption, comprising the steps of:
(a) generating a cryptographic key for the ECU using a master password, a serial number of the ECU, and a password-based key derivation function, wherein the cryptographic key is suitable for direct use by a cryptographic primitive;
(b) converting the generated cryptographic key into an ECU password; and
(c) accessing data from the ECU using the ECU password.
2. The method of claim 1 , wherein a length of the master password is chosen based on a character set size.
3. The method of claim 1 , further comprising the step of associating a vehicle part number with the master password.
4. The method of claim 1 , wherein the password-based key derivation function is defined in request for comment (RFC) 2898 published by the Internet Engineering Task Force.
5. The method of claim 1 , further comprising initiating a counter of the password-based key derivation function at a value greater than 1000.
6. The method of claim 1 , wherein the master password is greater than or equal to 64 bits.
7. The method of claim 1 , further comprising converting the generated cryptographic key into the ECU password using a modulo operator.
8. The method of claim 1 , further comprising the step of analyzing the cryptographic key for bias.
9. The method of claim 1 , further comprising the step of reducing a probability of a modulo bias by using one or more additional bytes of key material output from the password-based key derivation function.
10. The method of claim 1 , further comprising the steps of:
receiving the serial number from a user;
generating the ECU password from the received serial number and the master password at a location remote from the user; and
transmitting the ECU password to the user.
11. A method of regulating access to an electronic control unit (ECU) using encryption, comprising the steps of:
(a) electronically receiving a master password from a central facility;
(b) detecting a serial number of the ECU;
(c) providing the master password and the serial number to a password-based key derivation function;
(d) outputting a cryptographic key based on the master password and the serial number; and
(e) converting the cryptographic key into an ECU password.
12. The method of claim 11 , wherein a length of the master password is chosen based on a character set size.
13. The method of claim 11 , further comprising the step of associating a vehicle part number with the master password.
14. The method of claim 11 , wherein the password-based key derivation function is defined in request for comment (RFC) 2898 published by the Internet Engineering Task Force.
15. The method of claim 11 , further comprising initiating a counter of the password-based key derivation function at a value greater than 1000.
16. The method of claim 11 , wherein the master password is greater than or equal to 64 bits.
17. The method of claim 11 , further comprising the step of analyzing the cryptographic key for bias.
18. The method of claim 11 , further comprising the steps of:
receiving the serial number from a user;
generating the ECU password from the received serial number and the master password at a location remote from the user; and
transmitting the ECU password to the user.
19. The method of claim 11 , further comprising the step of writing the ECU password to memory of the ECU.
20. A method of providing unique passwords for a plurality of electronic control units (ECUs) using a master password common to the ECUs, comprising the steps of:
(a) producing a plurality of vehicle system modules for vehicles, wherein the vehicle system modules have a common vehicle part number and a serial number that is unique to each of the vehicle system modules;
(b) generating an ECU password for each vehicle system module using the serial number unique to that vehicle system module and a master password associated with the common vehicle part number; and
(c) storing the generated ECU password in each vehicle system module.