Storing vehicle data

1. A computer comprising a processor and a memory, the memory including instructions such that the processor is programmed to:

generate, upon detecting a vehicle entry device, a first data block including a hash of identification data for the entry device; and

generate, upon detecting a trip event, a second data block including a hash of trip event data and a hash linking the second data block to the first data block.

2. The computer of claim 1 , wherein the hash linking the second data block to the first data block is a hash of data in the first data block.

3. The computer of claim 1 , wherein the processor is further programmed to:

include a hash of a vehicle identification number for a first vehicle in the first data block, wherein the first vehicle includes the computer.

4. The computer of claim 3 , wherein the processor is further programmed to:

include a hash of data indicating at least one of a time of detecting the entry device, data indicating a date of detecting the entry device and data indicating a location of detecting the entry device.

5. The computer of claim 4 , wherein the processor is further programmed to:

include a hash of (1) the hash of identification data for the entry device; (2) the hash of the vehicle identification number for the first vehicle; and (3) the hash of data indicating at least one of the time of detecting the entry device, the data indicating a date of detecting the entry device and the data indicating a location of detecting the entry device in the first data block.

6. The computer of claim 1 , wherein the processor is further programmed to:

form a network with at least one second computer included in at least one respective second vehicle during a trip.

7. The computer of claim 6 , wherein the processor is further programmed to:

select at least one of the first data block and the second data block to store on a second computer in the network; and

transmit the selected at least one data block to the second computer to be stored during the trip.

8. The computer of claim 7 , wherein the processor is further programmed to:

transmit a third data block specifying terms for storing the at least one data block together with the at least one data block.

9. The computer of claim 6 , wherein:

the network is an ad-hoc network including a plurality of nodes, each of the plurality of nodes comprising a computer in a respective vehicle; and

each of the vehicles is communicatively coupled via wireless vehicle-to-vehicle communication with at least one other vehicle.

10. The computer of claim 1 , wherein the processor is further programmed to:

monitor a vehicle communications bus;

detect data indicating a trip event on the vehicle communications bus; and

determine that the trip event is detected based on the data indicating a trip event.

11. The computer of claim 1 , wherein the trip event is an action taken by a user of a first vehicle including the computer.

12. A method comprising:

generating, upon detecting a vehicle entry device, a first data block including a hash of identification data for the entry device; and

generating, upon detecting a trip event, a second data block including a hash of trip event data and a hash linking the second data block to the first data block.

13. The method of claim 12 , wherein the hash linking the second data block to the first data block is a hash of data in the first data block.

14. The method of claim 12 , further comprising:

including:

a hash of a vehicle identification number for a first vehicle in the first data block, wherein the first vehicle includes the computer; and

a hash of data indicating at least one of a time of detecting the entry device, data indicating a date of detecting the entry device and data indicating a location of detecting the entry device.

15. The method of claim 14 , further comprising:

including a hash of (1) the hash of the identification data for the entry device; (2) the hash of the vehicle identification number for the first vehicle; and (3) the hash of data indicating at least one of the time of detecting the entry device, the data indicating a date of detecting the entry device and the data indicating a location of detecting the entry device in the first data block.

16. The method of claim 12 , further comprising:

forming a network with at least one second computer included in at least one respective second vehicle during a trip.

17. The method of claim 16 , further comprising:

selecting at least one of the first data block and the second data block to store on a second computer in the network; and

transmitting the selected at least one data block to the second computer to be stored during the trip.

18. The method of claim 17 , further comprising:

transmitting a third data block specifying terms for storing the at least one data block together with the at least one data block.

19. The method of claim 16 , wherein:

the network is an ad-hoc network including a plurality of nodes, each of the plurality of nodes comprising a computer in a respective vehicle; and

each of the vehicles is communicatively coupled via wireless vehicle-to-vehicle communication with at least one other vehicle.

20. The method of claim 12 , further comprising:

monitoring a vehicle communications bus;

detecting data indicating a trip event on the vehicle communications bus; and

determining that the trip event is detected based on the data indicating a trip event.