San Francisco, USA — Open‑source software released today could significantly lower transaction fees on zero‑knowledge rollups, potentially ending the trade‑off between low cost and strong security that has long defined Ethereum layer‑2 scaling.
The code, named “Venus,” was published by Cysic, a verifiable compute network. It is a hardware‑optimized proving backend built on top of Zisk, an existing open‑source zkVM originally developed by the Polygon Hermez team (now independent). By accelerating the generation of zero‑knowledge proofs on GPUs, FPGAs, and eventually ASICs, the new code addresses the primary reason ZK‑rollups have remained more expensive than their optimistic counterparts.
The Persistent Cost Disadvantage of ZK‑Rollups
Optimistic rollups such as Arbitrum, Optimism, and Base offer low fees and fast throughput but require a seven‑day withdrawal window to allow for fraud proofs. ZK‑rollups provide instant finality and stronger cryptographic guarantees, but their proof generation has historically been computationally heavy – a cost passed on to end users.
As a result, many developers and users have opted for optimistic rollups, accepting slower withdrawals and weaker security models to save on fees. The industry has treated this as an unavoidable compromise.
Zisk Advanced ZK Proving – But Hit a Hardware Ceiling
Zisk, released by the Polygon Hermez team, represented a major leap forward. Its segmented proving model and RISC‑V‑based architecture achieved roughly 10‑fold faster trace generation than any other public zkVM at the time. For the first time, a general‑purpose zkVM could run on consumer hardware.
However, Zisk was designed as a CPU‑first system. Its GPU support was added through a hardware abstraction layer that treated the proving pipeline as an opaque black box. This resulted in high CPU‑GPU synchronization overhead, inefficient kernel launches, and no ability to globally optimize the proof flow. Support for FPGAs and ASICs – which can run ZK operations orders of magnitude faster – was absent.’
Zisk made ZK proving faster, but not fast enough to close the cost gap with optimistic rollups.
Venus: Hardware Acceleration for Zisk
To solve this problem, Venus replaces Zisk’s CPU‑first proving pipeline with a visible, composable computational graph. Instead of a single opaque prove() call, every operation – field arithmetic, hashing, Merkle tree updates – becomes a node that can be globally optimized.
Key features of the Venus release:
- Native CUDA Graph integration – Allows GPUs to run autonomously, eliminating CPU‑GPU synchronization delays. Early benchmarks on an RTX 5090 show a measurable throughput improvement over the Zisk baseline, with further gains expected.
- Full FPGA backend – Includes HLS kernels for Goldilocks field arithmetic, NTT, Poseidon2, Merkle trees, FRI, and expression evaluation, targeting AMD UltraScale+ and Versa l devices with HBM.
- Preliminary ASIC design – An initial implementation of a custom silicon path for zkVM proof acceleration.
- Open‑source licensing – Released under Apache 2.0 / MIT, the same permissive licenses as Zisk.
The code is under active development and has not yet been audited for production use. Cysic has invited the community to test, contribute, and build upon it.
What the Release Means for Layer‑2 Fees
If adopted by rollup operators and prover networks, Venus could significantly reduce the cost of generating ZK proofs. Lower proof costs would translate directly to lower transaction fees on ZK‑rollups – potentially making them price‑competitive with optimistic rollups for the first time.
More importantly, the release removes the economic penalty for choosing instant finality and cryptographic security over a seven‑day withdrawal window. Users would no longer have to choose between cheap and safe.
Industry observers note that widespread integration will take time. Rollup operators must update their prover infrastructure, and the code requires further testing and auditing. However, the release of Venus establishes a clear path toward a future where ZK‑rollups are no longer a premium product.
About the Release
Venus is available today on GitHub. It is built on Zisk, which remains under the stewardship of SilentSig Switzerland GmbH (the independent company spun out from Polygon Hermez). Cysic has contributed its hardware acceleration work back to the open‑source community under the same dual license.
GitHub: github.com/cysic-labs/venus
Quote from Cysic
“ZK‑rollups have always been the superior scaling solution – except for cost. Venus is our contribution to closing that gap. By open‑sourcing a hardware‑accelerated backend for Zisk, we are giving everyone the tools to run efficient provers. This is how we make ZK the default, not the premium option.”
Leo Fan, Founder of Cysic
About Cysic
Cysic is a verifiable compute network that combines custom hardware (ASICs, GPUs, FPGAs) with a decentralized prover marketplace to accelerate zero‑knowledge proof generation. The company’s infrastructure powers rollups, AI verification, and privacy‑preserving identity systems.
Website: cysic.xyz | Twitter: @cysic_xyz
