You’re identifying a real key-management problem, but you’re assuming that encryption requires one centralized master key. It doesn’t. Modern public-key cryptography is specifically designed so that encryption and decryption can be handled with separate keys, and key infrastructure can be compartmentalized so compromising one authority doesn’t automatically expose every other jurisdiction. There’s also an important technical distinction you’re collapsing: encryption protects confidentiality, while digital signatures protect authenticity and integrity. So if researchers recovered signing keys from some driver’s-license systems, that demonstrates weaknesses in those systems’ key management and authentication—it does not demonstrate that encryption itself is ineffective. Your alternative of “minimize what’s stored and allow open scrutiny” also isn’t really an alternative to encryption. We can do both. Data minimization reduces how much information is exposed; encryption protects information that does need to be stored or transmitted; digital signatures establish authenticity. These are complementary security controls. AAMVA’s current standards already use cryptographic security mechanisms for driver credentials, and its mobile-driver-license framework supports selective disclosure so a holder can provide only requested information. I’m also not arguing that lawmakers should hard-code a particular encryption algorithm into statute. That would be bad technology policy because cryptography evolves. The law should establish the security requirement, while technical standards bodies determine the implementation and update it as technology changes. And the status quo isn’t risk-free simply because current physical-license barcodes are generally readable. Under AAMVA’s 2025 standard, mandatory PDF417 data is unencrypted, meaning someone who obtains the barcode can potentially read its machine-readable fields without defeating encryption. So the question isn’t whether encryption creates any new attack surface—it does. The question is whether that key-management risk is outweighed by the privacy protection gained, and it can be mitigated through compartmentalized keys, hardware-protected private keys, key rotation, certificate revocation, and independent auditing. Your argument establishes “poor key management can create a serious security risk.” I agree. But it does not establish “an encryption mandate necessarily creates one centralized catastrophic key server.” That’s an assumption about implementation, not a necessary consequence of encryption. The better policy is to require strong cryptographic protection while requiring the key-management architecture to be decentralized, auditable, and resilient to compromise.

You're treating “requires a key” as “requires a single centralized online key infrastructure,” and that doesn't follow. A properly designed system can distribute and cache authorization keys, use jurisdiction-specific keys, and allow verification to continue during an outage rather than making every scan depend on one server. So the “single point” problem is an implementation risk, not an inherent consequence of encryption. I also think you're shifting the goalposts from privacy to convenience. Yes, unencrypted barcodes are cheaper and easier to scan. That's exactly why they're currently used. But if the barcode contains personal identifying information, readability by anyone with a scanner is itself a privacy risk. “Hard to forge” doesn't solve unauthorized disclosure. And your proposed solution—minimize stored data and sign it—still leaves whatever data remains completely readable to anyone who obtains the barcode. Signatures answer “Is this credential authentic?” Encryption answers “Who is allowed to read the data?” Those are different security problems. I'm not arguing that every random store clerk should need a complicated cryptographic setup just to verify an ID. The law can require privacy-preserving encryption while standards determine how authorized readers work, including offline-capable key caches and interoperable readers. And the cost argument needs an actual comparison: the existence of implementation costs doesn't establish that those costs exceed the privacy and identity-theft risks of exposing machine-readable personal data by default. Your argument successfully shows that encryption must be engineered carefully. It doesn't show that leaving sensitive barcode data unencrypted is the better security equilibrium. You're defending the cheaper status quo; I'm arguing that the security requirement should be set by law while the technical implementation remains flexible.

The problem with your argument is that you keep treating the existence of additional security infrastructure as evidence that encryption is worse than plaintext. More components can create additional attack surfaces, but that does not establish that the resulting system is less secure overall. By that logic, we would reject authentication, encryption, certificate systems, and access controls because each introduces key management and implementation risks. Your “game theory” point also needs an actual demonstrated equilibrium: saying attackers will target the weakest verifier doesn't show that an encrypted system has greater overall risk than an unencrypted one. In fact, an unencrypted barcode has an unavoidable weakness: anyone who can scan it can read the personal data. Your proposed fix—minimize the data and sign what remains—solves authenticity but not confidentiality. A signature can tell a verifier “this information came from the legitimate issuer and hasn't been altered,” but it cannot prevent an unauthorized person from reading that information. And you haven't established that your alternative is actually cheaper or more resilient; you're asserting those outcomes without comparing the costs or risks. Most importantly, I'm not arguing that every scan should depend on a live centralized server. A properly designed system can use issuer-specific keys, offline verification, cached trust information, expiration and revocation mechanisms, and standards that allow readers to update securely. Those are engineering questions, not reasons to prohibit the security requirement itself. The law doesn't need to dictate one algorithm or one architecture. It can require that sensitive machine-readable license data receive cryptographic confidentiality protection, while technical standards determine how that requirement is implemented and updated. So your argument establishes that encryption has implementation costs and must be engineered carefully. I agree with that. What you still haven't established is the crucial claim: that those costs and attack surfaces outweigh the privacy risk of deliberately leaving personal license data readable by anyone with a scanner. Until you demonstrate that, “cheaper” is an assertion, not an argument.

You’ve now changed the argument from “encryption is bad” to “we could avoid needing encryption by redesigning the barcode to contain almost no sensitive information.” That’s a legitimate alternative, but it doesn’t defeat my position because data minimization and encryption are not mutually exclusive. In fact, the strongest system can do both: minimize what the barcode contains AND cryptographically protect whatever sensitive information remains. Your “opaque ID + signature” proposal also creates its own dependency: the verifier still needs a trusted system to resolve that opaque identifier into information about the person, which means you haven’t eliminated infrastructure—you’ve moved it somewhere else. And the claim that encryption creates an “indefinite arms race” is still an assertion. Every security system requires maintenance, including signed credentials, certificate revocation, reader updates, and fraud monitoring. That doesn’t mean we abandon the security mechanism. More importantly, your proposal only works if the barcode contains almost nothing useful. But the moment legitimate verification requires additional information—such as identity attributes, restrictions, expiration, or other credential data—you’re back to the question of how that information is protected from unauthorized readers. A signature answers whether the data is authentic; it does not answer whether the person scanning it is authorized to see it. That is precisely the gap encryption addresses. I agree that legislation shouldn’t freeze one specific cryptographic algorithm into law. But requiring a security outcome is completely different from mandating one implementation. The law can require both data minimization and confidentiality, while technical standards determine the algorithms, key-management architecture, offline capabilities, and update procedures. So your alternative isn't evidence that encryption is unnecessary; at most, it shows that encryption should be one layer of a broader privacy architecture. “Minimize, sign, scrutinize” can coexist with “encrypt.” You still haven’t shown why protecting sensitive data is a worse policy than deliberately leaving it readable by anyone with a compatible scanner.

The privacy improvement is straightforward: the license holder’s data is protected from unauthorized readers. Your proposal of an opaque ID plus signature is a valid privacy architecture, but it doesn't prove encryption is unnecessary; it simply moves the sensitive information off the barcode and into another system that must securely map that ID to a person. That creates its own infrastructure, access-control, availability, and breach risks. You also keep asserting that encryption creates a “bad Nash equilibrium,” but that isn't actually established by showing that attackers can target weak readers. A Nash equilibrium requires specifying the players, strategies, and payoffs and showing that neither side benefits from unilaterally changing strategy. Simply saying “attackers target the weakest point” doesn't establish that encryption produces a worse equilibrium than plaintext or an opaque-ID system. More importantly, your argument keeps treating data minimization and encryption as competing solutions when they solve different problems. Minimization asks, “How much information should exist?” Encryption asks, “Who is allowed to read the information that does exist?” The strongest design can answer both: store less information, authenticate it with signatures, and encrypt sensitive data that legitimately needs to be present. And I agree that legislation shouldn't mandate a specific algorithm or freeze today's cryptography forever. The law can require a security outcome—confidentiality of sensitive machine-readable license data—while technical standards determine the algorithms, key management, reader architecture, and update procedures. Your argument demonstrates that key management has costs and that minimizing data is valuable. I agree with both. But you still haven't demonstrated the crucial comparative claim: that those costs create more risk than leaving personal license information readable to anyone with a compatible scanner. “Minimize, sign, scrutinize” is not an argument against encryption. It's an argument for layered security.