#dusk $DUSK @Dusk There’s a place that stuck me for three whole days: privacy-chain transactions are all encrypted, and nodes can’t even see the transaction contents—so don’t we at least have to charge Gas and take a fee? Last night, I took a screenshot of the proof generation logs from three days of testing and pressed it, like a coaster, against the bottom of my iced Americano cup near the foldable chair. In the rental apartment, an old desk fan was squealing as it blew, shaking the draft source code on my table for about half a minute. I stared at the logic diagram of the Rusk virtual machine for three minutes without saying a word. I used to assume this was handled one of two ways: either the node could decrypt and see the details to charge you, or the user would fill in a higher Gas and get the difference refunded or pay the shortfall—until I finished reading the source code of the zero-knowledge Gas metering module and realized it was built right into the privacy boundary, even for billing.
At first I thought that ZK Gas metering module was just a normal Gas estimator wrapped in encryption. But once I looked closely at the VM execution logic, I understood it wasn’t designed to save Gas at all—it was designed specifically to plug the leaks of privacy. If a node could infer what contract you executed and how much money you transferred just from Gas consumption, then all the prior transaction encryption would basically be wasted.
This mechanism just happened to seal the privacy leak that I’d been unable to route around for three days. It’s the Citadel billing-proof module built into the Rusk VM: compile the Gas calculation logic directly into a PLONK circuit. When the user generates the proof, it automatically computes the compliant Gas value. The node doesn’t need to decrypt the transaction— it only verifies the proof result. It’s completely the opposite of the competitor plan of “off-chain estimation + node plaintext verification.” With this approach, the node can’t see any execution details at all. The privacy boundary stretches from the transaction to the billing step; even Gas characteristics can’t be traced. My test showed single-proof generation takes 1.9 seconds—slower than Ethereum nodes computing Gas in plaintext, but it completely blocks the side-channel leakage paths.
But I also have to be honest: putting Gas calculation into a ZK circuit increases proof-generation complexity by about 30%. For newcomers who manually fill in Gas, they can easily get stuck due to prediction error. With fixed Gas parameters that aren’t yet dynamically adapted to complexity, during congestion there may be a premium. Timing and optimizations haven’t been disclosed yet either—we’ll have to wait for mainnet verification.
Whether this path can run smoothly still depends on mainnet data validation, but at least it shows that Dusk’s seriousness about privacy isn’t just slogans. Even the billing layer—one of the easiest things to overlook—didn’t get left out. If you’re building a privacy chain, do you think Gas-billing data should be hidden too? Let’s chat in the comments.
At first I thought that ZK Gas metering module was just a normal Gas estimator wrapped in encryption. But once I looked closely at the VM execution logic, I understood it wasn’t designed to save Gas at all—it was designed specifically to plug the leaks of privacy. If a node could infer what contract you executed and how much money you transferred just from Gas consumption, then all the prior transaction encryption would basically be wasted.
This mechanism just happened to seal the privacy leak that I’d been unable to route around for three days. It’s the Citadel billing-proof module built into the Rusk VM: compile the Gas calculation logic directly into a PLONK circuit. When the user generates the proof, it automatically computes the compliant Gas value. The node doesn’t need to decrypt the transaction— it only verifies the proof result. It’s completely the opposite of the competitor plan of “off-chain estimation + node plaintext verification.” With this approach, the node can’t see any execution details at all. The privacy boundary stretches from the transaction to the billing step; even Gas characteristics can’t be traced. My test showed single-proof generation takes 1.9 seconds—slower than Ethereum nodes computing Gas in plaintext, but it completely blocks the side-channel leakage paths.
But I also have to be honest: putting Gas calculation into a ZK circuit increases proof-generation complexity by about 30%. For newcomers who manually fill in Gas, they can easily get stuck due to prediction error. With fixed Gas parameters that aren’t yet dynamically adapted to complexity, during congestion there may be a premium. Timing and optimizations haven’t been disclosed yet either—we’ll have to wait for mainnet verification.
Whether this path can run smoothly still depends on mainnet data validation, but at least it shows that Dusk’s seriousness about privacy isn’t just slogans. Even the billing layer—one of the easiest things to overlook—didn’t get left out. If you’re building a privacy chain, do you think Gas-billing data should be hidden too? Let’s chat in the comments.