In Zero-knowledge systems, every line of code, every instruction, and every system-level choice becomes a part of a circuit that needs to be reproducible, verifiable, and secure not just today, but years from now. This is why getting architectural decisions right, all the way down to the ISA, is essential.
In most software environments, breaking changes to an underlying platform can be patched or migrated around. In ZK systems, that assumption breaks. Once an execution model is committed to a circuit, the cryptographic and logical constraints defined by that circuit must remain compatible. If the ISA changes - whether through opcode redefinition, extension, or semantic drift - then the entire constraint system becomes invalidated.
This breaks proofs. It breaks verifiers. And it breaks any system depending on those proofs being stable over time.
We refer to this problem as circuit rot: the gradual degradation of compatibility between code, execution, and the cryptographic proofs that attest to them - a structural risk embedded in fast-moving, unstable ISA ecosystems.
RISC-V is a powerful, modern ISA. But it was designed for a very different purpose: modular, extensible hardware innovation. That goal is reflected in its governance model and release cadence. The spec evolves regularly. Opcodes are added. Semantics are clarified or updated. Optional extensions are proposed and withdrawn. For hardware ecosystems, this model enables experimentation and progress.
For zero-knowledge circuits, it’s a liability.
Each ISA-level change forces a ripple effect through the decoder, trace model, and constraint system. Every downstream component must be rewritten, re-verified, and re-integrated, which is antithetical to reproducibility. In a proof system, these kinds of breaking changes translate to weeks or months of constraint migrations - and, worse, the invalidation of already-generated proofs.
In a ZK context, modularity and mutability at the ISA level introduce cryptographic fragility.
MIPS32r2, by contrast, is a stable, complete, and well-documented ISA that has not materially changed in decades. There are no active governance battles. No new extensions or breaking opcode proposals. No community-driven changes to instruction semantics.
This consistency is what makes MIPS ideal for zero-knowledge proving systems. Once a circuit is written to support the MIPS execution model, that circuit doesn’t rot. Programs compiled to MIPS32r2 today will continue to generate valid proofs tomorrow, next year, and beyond - without needing to rework the underlying constraint system.
This is the core of what we call ZK-proof longevity: the assurance that once something is made verifiable, it stays verifiable.
The industry has spent years building zero-knowledge circuits, only to watch tooling decay, constraint logic diverge, or opcode sets mutate out from under them. Each shift sets adoption back. Each migration adds complexity. For ZK to become a foundational layer of secure computation, it needs long-term guarantees.
Ziren is built for that. By grounding its architecture in MIPS32r2, ZKM has opted into an ecosystem that doesn’t shift beneath the developer’s feet. It’s not the easy path - the LLVM integrations, toolchain support, and constraint design all required deeper work. But it’s the correct one for infrastructure meant to last.
Programs compiled today to Ziren’s MIPS-based zkVM will produce proofs that remain valid indefinitely. This is how you build infrastructure, not just experiments.
Ziren: Build with Confidence. Deploy without Compromise.
Read Part 1: Why ZKM Chose MIPS32r2 Over RISC-V
Read Part 2: Microarchitectural Simplicity and Constraint Efficiency
In Zero-knowledge systems, every line of code, every instruction, and every system-level choice becomes a part of a circuit that needs to be reproducible, verifiable, and secure not just today, but years from now. This is why getting architectural decisions right, all the way down to the ISA, is essential.
In most software environments, breaking changes to an underlying platform can be patched or migrated around. In ZK systems, that assumption breaks. Once an execution model is committed to a circuit, the cryptographic and logical constraints defined by that circuit must remain compatible. If the ISA changes - whether through opcode redefinition, extension, or semantic drift - then the entire constraint system becomes invalidated.
This breaks proofs. It breaks verifiers. And it breaks any system depending on those proofs being stable over time.
We refer to this problem as circuit rot: the gradual degradation of compatibility between code, execution, and the cryptographic proofs that attest to them - a structural risk embedded in fast-moving, unstable ISA ecosystems.
RISC-V is a powerful, modern ISA. But it was designed for a very different purpose: modular, extensible hardware innovation. That goal is reflected in its governance model and release cadence. The spec evolves regularly. Opcodes are added. Semantics are clarified or updated. Optional extensions are proposed and withdrawn. For hardware ecosystems, this model enables experimentation and progress.
For zero-knowledge circuits, it’s a liability.
Each ISA-level change forces a ripple effect through the decoder, trace model, and constraint system. Every downstream component must be rewritten, re-verified, and re-integrated, which is antithetical to reproducibility. In a proof system, these kinds of breaking changes translate to weeks or months of constraint migrations - and, worse, the invalidation of already-generated proofs.
In a ZK context, modularity and mutability at the ISA level introduce cryptographic fragility.
MIPS32r2, by contrast, is a stable, complete, and well-documented ISA that has not materially changed in decades. There are no active governance battles. No new extensions or breaking opcode proposals. No community-driven changes to instruction semantics.
This consistency is what makes MIPS ideal for zero-knowledge proving systems. Once a circuit is written to support the MIPS execution model, that circuit doesn’t rot. Programs compiled to MIPS32r2 today will continue to generate valid proofs tomorrow, next year, and beyond - without needing to rework the underlying constraint system.
This is the core of what we call ZK-proof longevity: the assurance that once something is made verifiable, it stays verifiable.
The industry has spent years building zero-knowledge circuits, only to watch tooling decay, constraint logic diverge, or opcode sets mutate out from under them. Each shift sets adoption back. Each migration adds complexity. For ZK to become a foundational layer of secure computation, it needs long-term guarantees.
Ziren is built for that. By grounding its architecture in MIPS32r2, ZKM has opted into an ecosystem that doesn’t shift beneath the developer’s feet. It’s not the easy path - the LLVM integrations, toolchain support, and constraint design all required deeper work. But it’s the correct one for infrastructure meant to last.
Programs compiled today to Ziren’s MIPS-based zkVM will produce proofs that remain valid indefinitely. This is how you build infrastructure, not just experiments.
Ziren: Build with Confidence. Deploy without Compromise.
Read Part 1: Why ZKM Chose MIPS32r2 Over RISC-V
Read Part 2: Microarchitectural Simplicity and Constraint Efficiency
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