# Final Report: Rust KZG Tutorial and MSM Optimization

### **Author**
Li@only4sim

### **Project Goal**
When I started this project, my goal was ambitious but simple: to create the definitive, open-source guide to the `rust-kzg` library. This is a critical piece of Ethereum's future, but it's also incredibly complex. I wanted to crack it open for developers everywhere, making it easier for them to learn, use, and contribute to Ethereum's data availability layer.

Along the way, the project grew. After spending so much time documenting the library's internals, I saw a clear opportunity to not just explain it, but to make it better. So, a second goal emerged: to design a much faster algorithm for Multi-Scalar Multiplication (MSM), the library's biggest performance bottleneck.

### **Abstract**
This project was a two-part journey: first, to teach, and second, to build. The main result is a comprehensive, 20-chapter book on the `rust-kzg` library, now published on GitBook in both Chinese and English. It's a complete guide that takes a developer from the basic principles of cryptography all the way through to deploying a secure, high-performance service in production. It’s the playbook I wish I’d had when I started.

The second part of this journey was pure performance. I designed a new Multi-Scalar Multiplication (MSM) algorithm tailored specifically for the demands of Data Availability Sampling. By combining several advanced techniques and validating the design with a rigorous operation-counting method, I proved that this new algorithm is **3.9 times faster** in theory than the standard approach. Together, this work helps strengthen the Ethereum ecosystem by making its core technology more accessible to developers while providing a clear blueprint for making it significantly faster.

### **Contributions & Impact**

Looking back, I'm proud of what this project has contributed to the Ethereum and Rust communities:

1. **The Complete Rust-KZG Tutorial:** A 20-chapter book is now live on GitBook. This guide demystifies a complex topic, meaning more developers can start building and contributing to Ethereum's core infrastructure, faster.
* **You can read it here:** [https://only4sim.gitbook.io/only4sim-docs/](https://only4sim.gitbook.io/only4sim-docs/)

2. **A Blueprint for a Faster MSM:** I authored a formal research paper, "Accelerating Data Availability Sampling," that lays out the design for a highly optimized MSM algorithm.
* **Impact:** This paper provides a clear, validated path for a nearly 4x performance boost in KZG commitment generation. For Ethereum validators, this means lower hardware costs and more efficient operation.
* **You can read it here:** [https://hackmd.io/@only4sim/HJZ9UtFgWx](https://hackmd.io/@only4sim/HJZ9UtFgWx)

3. **Giving Back to the Ecosystem:** Along the way, I also had the chance to contribute in small ways, like finding and reporting a bug in the `libp2p` library's tutorial, which helps make the path a little smoother for the next developer.

### **Project Description**

My project unfolded as a story in two acts.

**Act I: Building the Ultimate Guidebook**
The first and longest phase was creating the 20-chapter tutorial. I wanted to build a journey for the reader, starting with the fundamentals and gradually building up to expert-level topics. It wasn't enough to just show the code; I wanted to explain the *why* behind it all. The tutorial covers:
* **The Foundations:** We start with the core math of cryptography and the concepts behind EIP-4844.
* **The Architecture:** We dive deep into the `rust-kzg` library's design, exploring its flexible, multi-backend system and the highly optimized BLST engine.
* **The Advanced Playbook:** I made sure to cover the topics that are often glossed over but are critical for real-world use, like GPU acceleration, building bindings for other languages (C, Python, WebAssembly), and designing enterprise-grade APIs.
* **The Real World:** The final section is a complete guide to production, covering everything from performance tuning and security hardening to deploying with Docker and Kubernetes.

**Act II: The Hunt for Performance**
After spending so much time documenting the library, I knew exactly where the biggest performance bottlenecks were. This led to the second phase of the project: a deep dive into MSM optimization. I focused on the specific problem context of DAS (`n=4096`, fixed points) and designed a hybrid algorithm that combines the best of several techniques.

**Challenges I Faced:**
It wasn't all smooth sailing. I hit a real challenge like the "sliding window" method. I found that there were no clear specifications or reference implementations to work from. More importantly, the complexity and overhead it introduced might have actually made things *slower* for our specific problem size. This forced me to be pragmatic and focus on a combination of techniques I knew I could validate and that would provide a clear benefit.

### **Key Learnings**

This project taught me a lot, but a few things really stand out:

1. **Teaching is the Best Way to Learn:** Writing the tutorial forced me to understand the library at a level I never would have reached otherwise. The process of explaining a complex topic is the ultimate test of your own knowledge, and it was the perfect foundation for the optimization research.
2. **Not All Optimizations Are Worth It:** My struggle with the micro optimization was a powerful lesson in pragmatism. It's easy to get excited about a complex algorithm, but sometimes the simplest, most direct improvements are the most effective. The key is to analyze the trade-offs within your specific context.
3. **Prove It Before You Build It:** Using operation counting to validate my algorithm design was a game-changer. It allowed me to prove my idea was faster *before* writing a single line of complex Rust code. It’s a technique I will carry forward in all future performance work.
4. **Open Source is a Community:** Even the small bug report to `libp2p` was a reminder that we're all building on each other's work. Making any part of the ecosystem a little better helps everyone.

### **Future Plans**
I'm not done with this work. Here’s what I'm excited to tackle next:
1. **Implement the Optimized MSM:** The top priority is to turn that 3.9x theoretical gain into a real-world, milliseconds-faster implementation in the `rust-kzg` library.
2. **Keep the Tutorial Alive:** I plan to maintain the tutorial, keeping it updated with any changes to the library or Ethereum's roadmap. I'll also look into getting a professional translation done.
3. **Build More Tools:** I want to expand on the `kzg-cli` concept from the tutorial and build more tools that make life easier for developers and operators working with DAS.

### **Link to Final Deliverables**
The work itself is the best demo. I invite you to explore the two main deliverables:
* **The Complete 20-Chapter Tutorial on GitBook:** [https://only4sim.gitbook.io/only4sim-docs/](https://only4sim.gitbook.io/only4sim-docs/)
* **The MSM Optimization Research Paper:** [https://hackmd.io/@only4sim/HJZ9UtFgWx](https://hackmd.io/@only4sim/HJZ9UtFgWx)

### **Acknowledgments**
I want to say a huge thank you to my mentor for their guidance and support, which was invaluable throughout this entire journey. I'm also incredibly grateful to the Ethereum Foundation for the opportunity to be a part of the Protocol Fellowship. Finally, thank you to all the researchers and developers in the Ethereum community whose work provided the foundation for this project.