Vivokey Flex One/Fidesmo Tesla key

I found this project here -, which appears to be a Javacard applet for emulating a Tesla 3 ISO keyfob.

I am not a Javacard developer and am far from a capable of modifying this code to work for the Vivokey Flex One, but I currently cannot see a reason why this cannot be ported over to Fidesmo, allowing people to install a Tesla key app, rather than an entire implant (that is the size of a Flex One anyways)

I will try and play with getting it installed to my Fidesmo developer card, but I have no idea if it will work.

@amal do you see anything immediately that would prevent this from being used in a Flex One/Fidesmo card?

The biggest thing I am unsure of is that this applet (and Tesla) require large frame sizes commands. This applet requires a frame size of 96 bytes or higher (FSCI value >= 6)

I cannot find any frame size specifications for the JCOP 3 SecID P60 chip that is in the Flex One :confused:

We have a version of this already tested to be working with the Model 3… it was rejected from the Fidesmo app store over fears it would incur the wrath of Tesla… but we have… other plans.


damn, that’s really lame it was rejected from Fidesmo; it infringes on no Testa technologies or patents or copyrights or intellectual property.

In fact, they could block this if they enable key checking, otherwise all this is doing is emulating a tag.
It’s up to Tesla to say “we don’t want you to do this”.

No matter what thought, you can take the compiled applet and install it manually on a Flex One or on a Fidesmo card.

1 Like

I don’t think this is possible due to the RID/AID requirements. I could be wrong… it’s been a long time since I have attempted it, but I don’t think the Fidesmo platform will even allow applet loading if the RID/AID is not permitted. The keycard applet requires a specific AID and the RID prefix is not enabled unless you request it… it was this request that was denied for me.

Incorrect; I’m the person who built the Tesla applet Amal’s discussing. We used Darconeous’ spec (the writer of Gauss), and liased with him on a few points before his applet was released.

The frame sizing is not an issue, i have tested with the component chip of the Flex One. It’s wholly a “politics” thing. Fidesmo only allow their RID or a RID you own/a well-known RID (like OpenPGP’s RID). Exemptions to their RID are at their discretion. We argued it was a well-known one, but they disagreed.

Fidesmo controls the ecosystem; if they say no to an applet, it doesn’t get installed.

You’ll also find Tesla recently released NFC key via phone, with no cert checking.