The keys are the keys to the car itself: a digital signature starts the engine.

The test is whether, as of July 2025, a cryptographic digital signature could authorize starting a car's engine, so that whoever holds the keys controls the car, including onchain (blockchain) keys as the proposition states. True: technical documentation or reliable reporting shows production or deployed vehicles whose start is authorized by a digital-signature challenge-response (e.g. phone or NFC digital keys using public-key cryptography), and shows working systems in which blockchain or onchain keys control vehicle access or ignition. Mostly true: digital-signature-based keys are shown to start production cars, while onchain-key control exists only in pilots or prototypes. Mixed: digital signatures are used in car access or immobilizer systems, but the evidence does not show they authorize starting the engine itself, or the onchain link is undemonstrated. Mostly false: only symmetric-key or rolling-code systems that are not digital signatures start cars, and the claim stretches a loose analogy. False: no car's engine can be started by a digital-signature-based authorization.

Set before the research began.

1. E1 Access key types Apple Support (Apple Platform Security guide) · 24 October 2026

   “Car keys can be used, for example, to unlock and lock the vehicle, open and close the trunk, turn the alarm on and off, start the engine, or set the vehicle into drive mode. The standard transaction offers mutual authentication and is mandatory for engine start.”

2. E2 Car key security in iOS Apple Support (Apple Platform Security guide) · 28 January 2026

   “Upon acceptance of the invitation, the recipient's device retrieves key creation data from the relay server mailbox and creates a digital key according to the CCC Digital Key Specification. As a part of key creation process, the key is signed by the sender.”

3. E3 [PDF] Compromising Keyless Entry System of Model 3 - NDSS Symposium NDSS Symposium (Fudan University / Shanghai Fudan Microelectronics authors) · February 2023

   “The core of authentication is two attestations generated by AES-GCM. The shared secret derived from ECDH is directly used as the key to encrypt the message that is known to both sides.”

4. E4 Balaji Srinivasan Says Crypto Is the 'Code-Based Order' for a Fracturing World Bitcoin.com News · 21 February 2026

   “The next leap, he wrote, involves physical infrastructure: homes unlocked via token verification, vehicles started by digital signatures, and capital equipment secured through blockchain-based control systems.”

Apple's platform security guide shows that digital car keys can start the engine, with a mutual-authentication transaction required for engine start (E1); the guide describes these keys as created under the CCC Digital Key Specification (E2). The same guide says keys are cryptographically signed when shared (E2), but neither source states that a digital signature is what authorizes the engine start. For the Tesla Model 3 keyless entry system, a security paper describes authentication based on AES-GCM attestations using an ECDH-derived key, not a digital signature (E3). No evidence shows working systems where onchain keys control a car, and E4 describes signature-started vehicles as a future "next leap", which matches the criteria's "mixed" case.