What is Ethash?
Ethash is the proof-of-work consensus algorithm powering Ethereum cryptocurrency. It evolved from Dagger-Hashimoto and incorporates Keccak (standardized as SHA-3) hash functions, though it's distinct from SHA-3 itself.
👉 Discover how Ethereum's mining algorithm compares to Bitcoin's
Key Features of Ethash
Memory-Hard Design:
- Uses a 1GB DAG dataset and 16MB cache
- Resets every 30,000 blocks (epoch)
- Dataset grows with each epoch
ASIC Resistance:
- Heavy memory requirements neutralize ASIC advantages
- Random memory accesses limit specialized hardware benefits
| Component | Initial Size | Growth Factor |
|---|---|---|
| DAG Dataset | 1GB | Increases per epoch |
| Cache | 16MB | Increases per epoch |
Mining Process Explained
Miners must:
- Store the entire DAG dataset
- Continuously compute MIX values using SHA-3
- Find valid nonces through memory-intensive operations
Light clients only need the cache for verification.
Why Memory Matters in Proof-of-Work
Ethash counters centralization by:
- Making GPU mining viable against ASICs
- Preventing mining dominance by specialized hardware
- Supporting decentralized participation
👉 Learn about Ethereum's transition to proof-of-stake
Frequently Asked Questions
What makes Ethash different from Bitcoin's algorithm?
Ethash emphasizes memory usage rather than pure processing power, making it resistant to ASIC optimization that occurred in Bitcoin mining.
How often does the DAG dataset change?
The dataset recalculates every 30,000 blocks (about 5.2 days at 15-second block times).
Can I still mine Ethereum with GPUs?
Yes, GPUs remain effective for Ethash mining due to its memory-oriented design, unlike Bitcoin which became ASIC-dominated.
Is Ethash being phased out?
Ethereum plans to transition to proof-of-stake (Ethereum 2.0), which will replace mining entirely with staking mechanisms.
Historical Context
Ethash was specifically designed to:
- Maintain network decentralization
- Allow consumer hardware participation
- Resist mining centralization seen in Bitcoin
For developers and miners alike, understanding Ethash remains crucial for Ethereum participation until the full transition to Ethereum 2.0.