Ethash is an open-source proof-of-work algorithm for Ethereum 1.0, written for developers, miners and researchers who want to study or run the original Ethereum mining scheme on Windows. It is free, and a ready-made Windows build or installer is available alongside the source code. The current release is v1.1.0, and the code was last updated on June 8, 2025, so the project is active rather than abandoned.
The program is narrow by design. It implements one algorithm, which descends from the Dagger-Hashimoto design and defines how proof-of-work hashes are computed on the original Ethereum chain. If you need a general-purpose wallet or a trading tool, this is not that kind of program.
What Is Ethash and Why Does It Matter?
Proof of work is the mechanism that once secured Ethereum by requiring miners to perform large amounts of hashing to add blocks. Ethash was the algorithm that defined that work on Ethereum 1.0, the original network before it moved to proof of stake.
Because the network no longer uses proof of work, Ethash is now mostly of historical and technical interest. It remains useful for anyone who wants to understand how Ethereum's early mining worked, or who needs to reason about the rules that governed block production in that era.
Understanding Ethash also helps when comparing consensus designs. Looking at why its authors chose memory-heavy computation shows how protocol designers balance accessibility, decentralization and resistance to specialized hardware.
How Memory-Hard Proof of Work Works
Ethash is described as memory-hard, meaning the algorithm requires a large block of data to be held in memory while it runs. That data is derived from a seed and grows over time, and a light cache is a smaller version used for verification.
The idea is to make the computation depend on memory access rather than raw processing speed alone. A design like this was meant to keep ordinary graphics hardware competitive and to make it harder for highly specialized chips to gain a large advantage.
For a reader, the practical takeaway is that memory size often limits what can be computed, more than clock speed does. This is why the dataset and cache calculations are central to understanding the algorithm.
Who Is Ethash For? Practical Use Cases
Ethash is most useful for developers who maintain tools that reference Ethereum 1.0 mining parameters, or who need a clear reference implementation for education. A student writing a thesis on consensus mechanisms, for example, can read the source and trace how the calculations are built.
Researchers comparing proof-of-work designs can use the code to test how memory requirements change as parameters shift. This kind of analysis is easier with working code than with a written specification alone.
Hobbyists who want to explore historical blockchain software may also find it a helpful starting point. The project is most valuable to people who are comfortable reading technical documentation and working with build tools.
Key features
Open-source code
Windows build or installer
Dataset and cache calculations
Python and C/C++ codebase
Supported coins
Ethash is associated with Ethereum (ETH) and the Ethash mining algorithm. It was designed for Ethereum 1.0, the original proof-of-work version of the network, so it does not apply to the proof-of-stake Ethereum that operates today.
How to install Ethash on Windows
- 1
Get the release
Download the Windows build or installer from the official website or the project's GitHub Releases page. Choose the latest release, which is v1.1.0 at the time of writing, and avoid copies shared through forums or file-sharing sites.
- 2
Verify the file
Compute the SHA-256 checksum of the downloaded file and compare it with the value published alongside the release. If the project provides a signature, verify that as well before running anything.
-
Install and confirm
Run the installer or extract the build to a folder you control, then confirm the installed version matches the release you downloaded. Keep the file in a dedicated location so updates are easy to track.
How to use Ethash
Ethash is a technical component rather than a point-and-click application, so the workflow is more about running calculations and reading the output. Start with a clear goal, such as checking the dataset size for a given block range, and work through the steps below.
- Install the Windows build or installer and confirm the version.
- Open a command prompt in the folder where the program is installed.
- Review the project documentation on the GitHub repository to confirm the expected input format.
- Run the dataset and light cache calculation for the parameter you want to examine.
- Save the output so you can compare results across runs.
- Compare the figures with the specification or with a second implementation to check accuracy.
- Document your settings so the results can be reproduced later.
- Update to the newest release when the project publishes one, after verifying the checksum again.
Pros & cons
- Free to use with no listed price
- Open-source code that can be read and audited
- Windows build or installer available
- Focused on one well-defined algorithm
- Source code can be built from scratch for customization
- Narrow scope limited to a single algorithm
- Built for Ethereum 1.0, which is no longer the live network
- Best suited to users comfortable with technical tools
- Not a wallet or general-purpose application
Is Ethash safe?
Download Ethash only from the official website or the project's GitHub Releases page. Verify the SHA-256 checksum or signature before running the file, and keep a copy of the checksum for future comparison. Be cautious of mirror sites and bundled installers from unknown sources.
The project was last updated on June 8, 2025, and it has not been marked as deprecated, so it is not abandoned. Still, check the latest version on the official website before installing. Because mining-related software is often flagged by antivirus tools, you may see warnings. Do not disable your protection entirely; instead, investigate the flag, and add a narrow exception only after verifying the file. Never enter a seed phrase on a third-party website.
- Official source only. Download from github.com/chfast/ethash. Ignore ads and lookalike domains.
- Check the SHA-256. Compare the installer hash with the value the developer publishes before running it.
- Never share your seed phrase. No developer, support agent or website — including CryptApps — will ever ask for it.
Alternatives
Ethash differs from RandomX in the kind of work it requires. RandomX is a proof-of-work algorithm based on executing random code, which is designed around general-purpose processors, while Ethash centers on a memory-heavy dataset tied to Ethereum 1.0. Choose RandomX if your interest is in that CPU-oriented design, and Ethash if you are studying the original Ethereum scheme.
MEV Boost works at a different layer entirely. It is Ethereum block-building middleware, so it addresses how blocks are assembled on the modern network rather than how proof-of-work hashes are computed. Trueblocks Core focuses on reading and organizing blockchain data, which makes it useful for analysis rather than consensus research.
Specifications
- Price
- Free
- Type
- Open source
- License
- —
- Latest version
- v1.1.0
- Last update
- 8 Jun 2025
- Windows support
- Yes (Windows build or installer)
- Source code
- github.com/chfast/ethash
Frequently asked questions
Ethash is a proof-of-work algorithm that defined mining on Ethereum 1.0, the original version of the network. It is used today mainly for education, research and maintaining tools that refer to its parameters. Because Ethereum has moved to proof of stake, it is no longer the algorithm securing the live network.
It can be, if you take the usual precautions. Download it only from the official website or the GitHub Releases page, then verify the SHA-256 checksum or signature before running it. The project was updated in June 2025 and is not marked as deprecated, which is a positive sign.
No. Ethash was designed for Ethereum 1.0, which used proof of work. The live Ethereum network now relies on proof of stake, so Ethash does not secure current blocks. It remains relevant for studying the original design and its memory-hard approach.
Yes, Ethash is free to use and is distributed as open-source software. You can download the Windows build or installer or the source code without paying a fee. Always obtain it from a trustworthy source to avoid modified copies.
Download the latest release from the official website or GitHub Releases, then verify the checksum. Run the installer or extract the Windows build to a folder you control. Confirm the installed version matches the release you downloaded before you start working with it.
Both are proof-of-work algorithms, but they take different approaches. Ethash relies on a large memory-heavy dataset associated with Ethereum 1.0. RandomX is based on executing random code and is aimed at general-purpose processors. The right choice depends on whether you want to study Ethereum's original design or a CPU-focused alternative.
Verdict
Ethash is a good fit for developers, students and researchers who want to understand the original Ethereum proof-of-work design. It is free, open source and available as a Windows build or installer, and it has a recent code update. It is not a wallet or a general tool, and it does not secure the current Ethereum network. Before you install, check the latest version on the official website and verify the file.