# Dev Update Week 7: A Cross-Analysis of zkVM Precompiles

**Developer:** Developeruche
**Week Ending:** August 1, 2025

### Summary
This week, my research shifted from the host environment (Linux ABI) to the core of zkVM performance: **precompiles**. The primary objective was to conduct a comprehensive survey across the leading zkVMs to understand the current landscape of hardware-accelerated operations. By cataloging and categorizing the precompiles used by seven major zkVMs, I have begun to identify common patterns, areas of specialization, and potential redundancies. This foundational work is the first step toward defining a minimal, standardized, and highly efficient set of precompiles for future zkVM designs.

### Accomplishments This Week
* **Comprehensive Precompile Catalog:** I successfully surveyed and documented the precompile sets for seven major zkVMs: **RISC0, SP1, Airbender, Zisk, OpenVM, Ziren, and Pico**. This provides a wide-angle snapshot of the current state of zkVM acceleration.
* **Functional Categorization:** I organized the collected precompiles into distinct functional categories:
* **Hashing:** (e.g., `SHA-256`, `Keccak256`, `Blake`)
* **Big Integer Arithmetic:** (e.g., `BigInt`, `u256`)
* **Elliptic Curve Cryptography (ECC):** (e.g., `secp256k1`, `bn254`, `edwards`, `weierstrass` operations)
* **Finite Field Arithmetic:** (e.g., `fp`, `fp2` operations)
* **Initial Comparative Analysis:** I performed a preliminary comparison, identifying a core set of common precompiles (`SHA-256`, `BigInt`) present in most zkVMs, while noting significant divergence in the scope and granularity of cryptographic suites.

### Comparative Analysis: Initial Findings

The survey reveals a clear spectrum of precompile strategies:

| zkVM | Hashing | BigInt | ECC Curves | Finite Field | Notes |
| :--- | :--- | :--- | :--- | :--- | :--- |
| **RISC0** | SHA-256 | Yes | - | - | Minimalist, focused on general computation. |
| **SP1** | SHA-256, Keccak256 | Yes | Edwards, Weierstrass | Yes | Broad support for common crypto primitives. |
| **Airbender**| Blake | Yes | - | - | Focus on a different hash standard. |
| **Zisk** | SHA-256, Keccak | Yes | secp256k1 | - | Optimized for Ethereum-like operations. |
| **OpenVM** | SHA-256, Keccak256 | Yes | Weierstrass, Pairings | Yes | Extensive support for advanced cryptography. |
| **Ziren** | SHA-256, Keccak | Yes | secp256k1, bn254, bls12381, secp256r1 | Yes | Extremely comprehensive, rollup-centric suite. |
| **Pico** | SHA-256, Keccak | Yes | secp256k1, bn254, bls12381 | Yes | Very similar to Ziren, indicating a convergence for rollup use cases. |

**Key Observations:**

* **Universal Primitives:** `SHA-256` and `BigInt` (or `u256`) arithmetic are nearly universal, establishing them as the bedrock of essential precompiles.
* **Divergence in ECC:** While `secp256k1` is common for its use in Ethereum, the inclusion of `bn254`, `bls12381`, and other curves is a clear indicator of a zkVM's focus on supporting ZK-SNARK verification and rollups.
* **Redundancy vs. Specialization:** The highly granular finite field arithmetic precompiles seen in Ziren and Pico (e.g., `bls12381FpAdd`, `bn254Fp2Mul`) offer maximum performance for specific cryptographic tasks. However, they raise the question of redundancy: could a more generalized `Fp` precompile achieve similar results with less complexity?

### Next Steps & Goals for Next Week

1. **Quantify Performance Gains:** The next critical step is to move from a qualitative to a quantitative analysis. I will research benchmarks and documentation to estimate the cycle-count reduction for key precompiles (e.g., one `sha256` precompile call vs. a pure software implementation in RISC-V).
2. **Formalize Redundancy Analysis:** I will deepen the analysis of functional overlap. For example, I will investigate if a generic `weierstrass add` precompile can be configured to handle multiple curves, potentially reducing the need for curve-specific precompiles.
3. **Draft a "Minimal Standard" Proposal:** Based on the analysis, I will begin drafting a proposal for a minimal, yet powerful, standard set of precompiles that balances generality with high performance, suitable for a next-generation, general-purpose zkVM.
4. **Investigate Precompile Extensibility:** I will research the mechanisms different zkVMs use to add new precompiles. Understanding the difficulty of extending the precompile set is crucial for long-term zkVM design.

### Challenges & Learnings

* **Challenge: Lack of Standardized Benchmarks:** Comparing performance gains across zkVMs is difficult due to the lack of standardized cycle-counting methodologies. The "cost" of a precompile is not always directly comparable.
* **Learning: Precompiles Tell a Story:** A zkVM's list of precompiles is a clear statement of its intended purpose. The difference between RISC0's minimalist set and Ziren's exhaustive cryptographic suite perfectly illustrates the divide between general-purpose and application-specific design philosophies.
* **Learning: The Generality vs. Performance Trade-off:** The core tension in precompile design is clear. Highly specific precompiles (like `bn254FpAdd`) offer the best performance for a single task but increase the complexity and surface area of the zkVM. More general precompiles are flexible but may carry a performance penalty. Finding the right balance is the central challenge.