Latest / Cybersecurity Business with Fexingo: Security Companies, Breaches, and Enterprise Defense / How Zero-Knowledge Proofs Can Prove a Breach Without Revealing Secrets
Transcript
- Lucas: So there's a moment in every breach response that rarely gets the attention it deserves, and it happens right after you've contained the attack, when you have to tell someone else about it. A regulator, a business partner, an auditor. And the tricky part is, they want proof. But the more proof you give, the more you expose the very vulnerabilities that got you into this mess. Luna: Right, it's like you're stuck between 'show me the evidence' and 'please don't tell the whole world how we got in.' Lucas: Exactly. And that's the tension I've been seeing a lot in enterprise security this year. Companies are required to disclose breaches under SEC rules, under state laws, under contractual agreements. But the disclosure itself can be a second breach, a leak of sensitive technical details that attackers can use to refine their next attempt. Luna: So how do you get around that? I mean, you can't just say 'trust us, we were breached.' Lucas: Well, that's where something called a zero-knowledge proof comes in. It's a cryptographic method where you can prove that a statement is true without revealing anything beyond the truth of that statement. Think of it like proving you know the password to a system without actually telling anyone the password. Luna: That sounds almost too good to be true. Has this ever actually been used in a breach notification? Lucas: It's still early, but I spoke with a CISO at a mid-sized bank who used a zero-knowledge proof to show their regulator that a credential-stuffing attack had been contained. They didn't have to reveal which accounts were affected, how they detected it, or what the attack vector was. Just a cryptographic guarantee that the breach happened and that it was over. Luna: That's fascinating. But I imagine that kind of proof isn't easy to generate. There's got to be a real computational cost. Lucas: There is. Zero-knowledge proofs are computationally intensive. Generating one can take minutes, even hours, depending on the complexity. But for a breach notification, that's not a deal-breaker. The bigger challenge is encoding the actual breach data into a format that can be proved. You need to define what 'contained' means in a way that's mathematically verifiable. Luna: So it's not like you just press a button and out pops a proof. You have to design the whole system around it. Lucas: Right. And that's a significant engineering effort. But there are companies building tools to make this more accessible, and the payoff is huge. Because if you can prove a breach without revealing sensitive details, you change the whole dynamic of breach disclosure. Luna: It's like you're finally giving CISOs a way to be honest without being reckless. Lucas: Exactly. And that honesty is critical, especially with regulators. The bank I mentioned, they were able to satisfy their examiners that they had actually contained the threat, without opening themselves up to additional risk. That's a real win. Luna: And it's not just for regulators. I imagine business partners and customers would also want proof, but they don't necessarily need to know the gory details. Lucas: Absolutely. A vendor might require you to disclose any breach that could affect their data. With a zero-knowledge proof, you can show that the breach didn't involve their data, or that it was fully remediated, without telling them which systems were affected. Luna: That could really change how companies vet their supply chains. It's a lot more than a checkbox on a questionnaire. Lucas: It is. But let's bring this back to something very practical. If you're running a business or building a product, and you're finding these conversations about security and privacy useful, there's a simple way to keep this show ad-free and independent. Head over to buy me a coffee dot com slash fexingo. It's just a way for listeners who get value from what we do to chip in and keep the lights on. Luna: Yeah, it really helps. And it's not a big ask. Even a small one-time contribution makes a difference for us. Lucas: So, back to the technical side. One of the most interesting applications I've seen is in threat intelligence sharing. Normally, if you share indicators of compromise with other companies, you're also revealing what your own network looks like. Attackers can study those indicators and adapt. But with zero-knowledge proofs, you can prove that a particular indicator was seen in your environment without actually sharing the indicator itself. Luna: So you're contributing to the collective defense without exposing your own weaknesses. That's a game-changer for information sharing and analysis centers. Lucas: It really is. And there's a lot of potential in incident postmortems too. When you do a postmortem, you often have to redact sensitive details before sharing internally. But with zero-knowledge proofs, you could verify that a specific control was tested and failed, without revealing the exact nature of the failure. Luna: That would make postmortems a lot more valuable. You could learn from each other's mistakes without embarrassing anyone. Lucas: Right. And the same logic applies to audit reports. Auditors want to verify that your security controls are effective. Normally, that means giving them access to your systems, your logs, your configurations. With zero-knowledge proofs, you could give them a mathematical assurance that a control is working, without handing over the underlying data. Luna: But wouldn't an auditor want to see the actual evidence? I mean, aren't they trained to be skeptical of digital magic? Lucas: You'd think so, but the technology is actually quite transparent. The proof itself can be verified independently, and it's just as strong, if not stronger, than a log file. Because you can prove that the log hasn't been tampered with, and that the control operated exactly as designed, over a specific time period. Luna: So it's not about hiding anything from the auditor. It's about giving them what they need without giving them everything else. Lucas: Exactly. And that's a big deal, because the current approach to audits is all-or-nothing. You either give the auditor access to your sensitive systems, or you don't. A zero-knowledge proof gives you a middle path. Luna: What about the computational overhead? Is that still a barrier for most companies? Lucas: It's decreasing, but it's not trivial. For a large enterprise with thousands of systems, generating a proof that covers all of them could be impractical. But you can do it in stages, or for specific high-value controls. The bank I mentioned, they focused on the critical accounts and the containment process, not the entire network. Luna: So it's about picking your battles. You don't need to prove everything, just the things that matter most. Lucas: Right. And there are also open-source libraries and frameworks that make it easier to implement zero-knowledge proofs without building everything from scratch. The learning curve is still steep, but it's getting more manageable. Luna: Are there any risks or downsides you're seeing? I mean, if this becomes standard, could attackers use zero-knowledge proofs to their advantage? Lucas: That's a good question. Attackers could potentially use zero-knowledge proofs to prove they have access to a system without revealing how, which could make extortion more credible. But that's a double-edged sword, because it also means defenders can prove they've mitigated a threat without giving away their playbook. Luna: So it's a tool that can be used for good or for ill, like any technology. Lucas: Exactly. And that's why it's so important for security professionals to understand it. If you don't know how zero-knowledge proofs work, you can't evaluate the claims that vendors might make about them. And there are already some vendors marketing zero-knowledge proofs for things like secure multi-party computation, which is related but different. Luna: So what's the one thing you want listeners to take away from this episode? Lucas: I think it's that breach disclosure doesn't have to be an all-or-nothing proposition. There's a way to be transparent and still protect your organization. Zero-knowledge proofs are still early, but they're already being used in real-world scenarios, and the potential is enormous. Luna: It definitely gives me a new perspective on what 'proof' can mean. I used to think it was just logs and screenshots, but now I see it's something more fundamental. Lucas: And that's the shift happening across cybersecurity. We're moving from a world where you have to take someone's word for it, to a world where you can verify without revealing. It's a subtle but profound change. Luna: A change that could make the whole industry a little more trustworthy, one proof at a time. Lucas: I think that's exactly right. And if you're curious about how this might apply to your own organization, start by looking at your breach notification requirements and see if there's a way to use a zero-knowledge proof to satisfy them. It's a conversation worth having with your security team.