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Model S Key fob won’t update to V2

ucmndd

Well-Known Member
Mar 10, 2016
7,712
14,998
California
Late 2018 is correct for the V2 fobs. They doubled the hash length on the new fobs (which doubled the time needed to decrypt them from 2s to 4s).

Some minor points here, as I can’t determine relative position of your tongue and cheek.

Theoretically, a 40 vs. 80 bit key is a trillion or so times harder to crack (2^40 possible combinations vs. 2^80). That said, with most encryption, the details are in the implementation and it does indeed appear that Tesla’s “80 bit” implementation was to use two 40 bit keys, which is decidedly not the same thing as an 80 bit key.

This update as I understand it is intended to fix that and implement a true 80 bit key.
 

Huachipato

Member
Jul 16, 2019
334
259
Murphy, TX
Some minor points here, as I can’t determine relative position of your tongue and cheek.

Theoretically, a 40 vs. 80 bit key is a trillion or so times harder to crack (2^40 possible combinations vs. 2^80). That said, with most encryption, the details are in the implementation and it does indeed appear that Tesla’s “80 bit” implementation was to use two 40 bit keys, which is decidedly not the same thing as an 80 bit key.

This update as I understand it is intended to fix that and implement a true 80 bit key.

The issue is, using your formula to explain - that it wasn't initially set up as 2^80. Instead, it was set up as (2^40)*2.
 
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zanary

Active Member
Jan 25, 2017
1,542
1,762
SF Bay Area (East Bay), CA
Is Tesla providing the new fobs for free (USA) for V1 customers? Or is there a charge, if so, what is the cost? Thanks!
They are not free. Schedule a mobile appointment and they come by and set it up for you.
I think the costs is around $200 or so. You get to keep your old v1 fob as well and you can have all three provisioned to your Model S if you want.
 

Tim-in-CA

Member
Apr 23, 2018
340
149
SoCal
They are not free. Schedule a mobile appointment and they come by and set it up for you.
I think the costs is around $200 or so. You get to keep your old v1 fob as well and you can have all three provisioned to your Model S if you want.

Thanks for the info. At this point, I don't think where I park (at home or at work) that I am suspect to key cloning / intercept (as I have seen on video). If I am really concerned, I'll enable pin-to-drive. But, I have a SC appointment this week, I'll ask … it doesn't hurt!
 

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