Cryptography is about finding and basing techniques on hardness assumptions, such as the one-time pad, factoring, or a system of linear equations such as learning with errors. A cryptographer then devises a cryptographic protocol with explicit guarantees.
However elegant a cryptographic mechanism might be, ultimately the constructions have underlying assumptions or simplified models whereby a cryptographic mechanism composed with other protocols or in a system will leak much more information than desired.
For example, zero-knowledge proofs which are an example. Zero-knowledge proofs are an elegant construction whereby a prover can demonstrably prove to a verify that that prover knows a certain piece of information without the prover ultimately revealing that piece of information. This is an extremely powerful construction that transformed static written down proofs into a dynamic interaction that is based on probabilistic techniques.
However, zero-knowledge proofs run many times or against an adaptive adversary will eventually leak enough information to reasonably infer the information being protected.
In general, security systems are composed of many different cryptographic techniques. Though it's the asymmetry of security that makes it exponentially tough to defend. A single vulnerability found by an adversary can topple an entire system against a motivated and well resourced adversary.
Incentives and game theory will become the final deterrant and offer protection to secure systems. In the distributed and connected vehicle architecture, we will need to define and determine exactly what these incentives are.
