Secured communication in passive entry passive start (PEPS) systems

1. A system for secure communication between a vehicle and a portable communication device, the system comprising:

a vehicle access system included in the vehicle, wherein the vehicle access system is configured to

wirelessly receive a shuffled message and a random number from the portable communication device, the shuffled message including a plurality of bits at bit positions 0 through n and the random number having a value specifying one of the bit positions 0 through n of the shuffled message,

de-shuffle the shuffled message at a bit level to obtain a message, wherein de-shuffling the shuffled message at the bit level includes exchanging one bit within the shuffled message positioned at the bit position specified by the value of the random number with another bit within the shuffled message, and

initiate a vehicle operation based on the message.

2. The system of claim 1 , further comprising:

the portable communication device, wherein the portable communication device is configured to

generate the random number,

shuffle the message at a bit level based on the random number to generate the shuffled message, and

wirelessly transmit the shuffled message and the random number to the vehicle access system.

3. The system of claim 2 , wherein the portable communication device is further configured append an identifier of the portable communication device and a cyclic redundancy check code to the message before shuffling the message.

4. The system of claim 2 , wherein the portable communication device is further configured to encrypt the shuffled message and the random number before transmitting the shuffled message and the random number to the vehicle access system.

5. The system of claim 4 , wherein the portable communication device is configured to encrypt the shuffled message and the random number by

performing a first encryption of the shuffled message and the random number in a Bluetooth application layer using encryption information exchanged during a pairing process performed between the vehicle and the portable communication device, and

performing a second encryption of the shuffled message and the random number in a Bluetooth stack layer using an encryption key and an initialization vector.

6. The system of claim 1 , wherein the vehicle access system is configured to de-shuffle the shuffled message in a Bluetooth application layer.

7. The system of claim 1 , wherein the vehicle access system is configured to wirelessly receive the random number by

receiving an initial random number,

splitting each byte of the initial random number into two portions, and

promoting each of the two portions to a byte to generate an extended random number, wherein the random number is one byte of the extended random number, and

wherein the vehicle access system is configured to exchange the one bit within the shuffled message positioned at the bit position specified by the value of the random number with another bit within the shuffled message by

(a) exchanging the one bit within the shuffled message positioned at the bit position specified by the value of the random number with a bit within the shuffled message positioned at a current highest bit position and

(b) decrementing the current highest bit position.

8. The system of claim 7 , wherein the vehicle access system is further configured to repeat (a) and (b) for each other byte of the extended random number in a predetermined order, wherein the predetermined order is opposite an order used by the portable communication device to generate the shuffled message.

9. The system of claim 1 , wherein the vehicle access system is further configured to decrypt the shuffled message before de-shuffling the shuffled message.

10. The system of claim 9 , wherein the vehicle access system is configured to decrypt the shuffled message by

performing a first decryption of the shuffled message in a Bluetooth stack layer using an encryption key and an initialization vector, and

performing a second decryption of the shuffled message in a Bluetooth application layer using encryption information exchanged during a pairing process performed between the vehicle and the portable communication device.

11. A method for secure communication between a vehicle and a portable communication device, the method comprising:

wirelessly receiving, with a vehicle access system included in the vehicle, a shuffled message from the portable communication device and a random number, the shuffled message including a plurality of bits at bit positions 0 through n and the random number having a value specifying one of the bit positions 0 through n of the shuffled message;

de-shuffling, with the vehicle access system, the shuffled message at a bit level to obtain a message, wherein de-shuffling the shuffled message at the bit level includes exchanging one bit within the shuffled message positioned at the bit position specified by the value of the random number with another bit within the shuffled message; and

initiating, with the vehicle access system, a vehicle operation based on the message.

12. The method of claim 11 , wherein de-shuffling the shuffled message includes de-shuffling the shuffled message in a Bluetooth application layer.

13. The method of claim 11 , wherein wirelessly receiving the random number includes

receiving an initial random number,

splitting each byte of the initial random number into two portions, and

promoting each of the two portions to a byte to generate an extended random number, wherein the random number is one byte of the extended random number, and

wherein exchanging the one bit within the shuffled message positioned at the bit position specified by the value of the random number with another bit within the shuffled message includes

(a) exchanging the one bit within the shuffled message positioned at the bit position specified by the value of the random number with a bit within the shuffled message positioned at a current highest bit position and

(b) decrementing the current highest bit position.

14. The method of claim 13 , further comprising repeating (a) and (b) for each other byte of the extended random number in a predetermined order, wherein the predetermined order is opposite an order used by the portable communication device to generate the shuffled message.

15. The method of claim 11 , further comprising decrypting the shuffled message before de-shuffling the shuffled message.

16. The method of claim 15 , wherein decrypting the shuffled message includes

performing a first decryption of the shuffled message in a Bluetooth stack layer using an encryption key and an initialization vector, and

performing a second decryption of the shuffled message in a Bluetooth application layer using encryption information exchanged during a pairing process performed between the vehicle and the portable communication device.

17. A vehicle access system installed in a vehicle, the vehicle access system comprising:

a wireless communication transceiver; and

an electronic processor,

the wireless communication transceiver configured to

wirelessly receive a shuffled message and a random number from a portable communication device, the shuffled message including a plurality of bits at bit positions 0 through n and the random number having a value specifying one of the bit positions 0 through n of the shuffled message;

de-shuffle the shuffled message at a bit level to obtain a message, wherein de-shuffling the shuffled message at a bit level includes exchanging one bit within the shuffled message positioned at the bit position specified by the value of the random number with another bit within the shuffled message, and

provide the message to the electronic processor,

the electronic processor configured to initiate a vehicle operation based on the message.

18. The vehicle access system of claim 17 , wherein the vehicle operation includes at least on selected from a group consisting of an unlock operation and a lock operation of a door of the vehicle.

19. The vehicle access system of claim 17 , wherein the wireless communication transceiver is configured to wirelessly receive the random number by

wirelessly receiving an extended random number, wherein the random number is one byte of the extended random number, and

wherein the wireless communication transceiver is configured to exchange the one bit within the shuffled message positioned at the bit position specified by the value of the random number with another bit within the shuffled message by

(a) exchanging the one bit within the shuffled message positioned at the bit position specified by the value of the random number with a bit within the shuffled message positioned at a current highest bit position and

(b) decrementing the current highest bit position, and

wherein the wireless communication transceiver is further configured to repeat (a) and (b) for each other byte of the extended random number in a predetermined order, wherein the predetermined order is opposite an order used by the portable communication device to generate the shuffled message.

20. The vehicle access system of claim 17 , wherein the wireless communication transceiver is further configured to decrypt the shuffled message before de-shuffling the shuffled message, wherein the wireless communication transceiver is configured to decrypt the shuffled message by

performing a first decryption of the shuffled message in a Bluetooth stack layer using an encryption key and an initialization vector, and

performing a second decryption of the shuffled message in a Bluetooth application layer using encryption information exchanged during a pairing process performed between the vehicle and the portable communication device.