Secure Hash Algorithm 256-bit
ASIC DominatedSHA-256 is the proof-of-work algorithm underpinning Bitcoin — the world's largest cryptocurrency by market capitalisation. Designed by the NSA and published in 2001, it produces a 256-bit hash and was selected by Satoshi Nakamoto for Bitcoin in 2008 for its security properties and computational predictability.
How SHA-256 Works
SHA-256 performs a series of bitwise operations, modular additions, and compression rounds on 512-bit blocks of data. Bitcoin mining requires finding a nonce such that SHA-256(SHA-256(block_header)) produces a hash below the current target value. The double-SHA-256 construction (SHA-256d) adds an additional layer of collision resistance. The algorithm is compute-bound rather than memory-bound, making it highly amenable to ASIC optimisation.
History & Evolution
Bitcoin launched with SHA-256 minable via CPU (2009), then GPU (2010), then FPGA (2011), before the first dedicated ASICs appeared in 2012. Each hardware generation delivered 10–1000× efficiency improvements. By 2014 GPU and CPU mining were economically obsolete. Today, SHA-256 ASIC generation cycles run roughly 18 months, with each new family improving energy efficiency by 15–30%.
Hardware Requirements
SHA-256 is the most mature ASIC market in existence. Bitmain (Antminer S-series), MicroBT (Whatsminer M-series), and Canaan (Avalon A-series) dominate production. The efficiency frontier in 2026 is approximately 11–12 J/TH for air-cooled models, down from ~90 J/TH for first-generation ASICs. GPU and CPU mining SHA-256 is not viable at any commercially available electricity rate.
Compatible Mining Software
Mining Pools for SHA-256
The Bitcoin SHA-256 pool landscape is dominated by a handful of large pools: Foundry USA, AntPool, F2Pool, and ViaBTC collectively represent ~60% of network hashrate. Pool selection matters for decentralisation; smaller pools like Braiins Pool (OCEAN) and SOLO options offer better Bitcoin network health.
How to Start Mining with SHA-256
- Choose hardware — SHA-256 is the most mature ASIC market in existence. Bitmain (Antminer S-series), MicroBT (Whatsminer M-series), and Canaan (Avalon A-series) dominate production. The efficiency fr.
- Install mining software — compatible options include: cgminer, BraiinsOS+ (recommended for Antminer), VNish firmware, Stock Bitmain/MicroBT/Canaan firmware.
- Select a pool — The Bitcoin SHA-256 pool landscape is dominated by a handful of large pools: Foundry USA, AntPool, F2Pool, and ViaBTC collectively represent ~60% of network hashrate. Pool selection matters for decent.
- Configure stratum URL and wallet — set
stratum+tcp://pool-url:portas pool address and your BTC/BCH wallet address as the username/payout address. - Start mining and monitor — check accepted shares in the pool dashboard within 5–10 minutes of startup.
- Track profitability — use our live calculator to monitor earnings vs electricity costs.
Frequently Asked Questions
Why does Bitcoin use SHA-256?
Satoshi Nakamoto selected SHA-256 for Bitcoin because it was a well-reviewed, collision-resistant hash function with predictable computation time — properties essential for a fair and consistent proof-of-work system. Its compute-bound nature (as opposed to memory-bound) also allowed the difficulty to scale predictably with hardware improvements over time.
Can I mine SHA-256 with a GPU or CPU in 2026?
No. SHA-256 ASIC miners are 100,000× more energy-efficient than CPUs and 1,000× more efficient than GPUs for SHA-256 computation. Attempting to mine Bitcoin or Bitcoin Cash with a GPU or CPU in 2026 would cost far more in electricity than any rewards earned. Dedicated SHA-256 ASICs are the only viable option.
What is the efficiency frontier for SHA-256 ASICs in 2026?
The best air-cooled SHA-256 ASICs in 2026 achieve approximately 11–12 J/TH. The Whatsminer M66S reaches 11.5 J/TH at 298 TH/s, and the Antminer S21 XP achieves 12 J/TH at 270 TH/s. Hydro-cooled models (like the S21 XP Hyd) match this efficiency at higher absolute hashrates. First-generation Bitcoin ASICs from 2013 consumed 900+ J/TH — an improvement of roughly 80× over 13 years.
What coins use SHA-256 besides Bitcoin?
Bitcoin Cash (BCH) also uses SHA-256, having forked from Bitcoin in 2017. Because both coins use identical hashing, any SHA-256 ASIC can mine either coin — or both via merge-mining setups. Other SHA-256 coins exist (Bitcoin SV, DigiByte SHA256 chain) but have much lower network difficulty and liquidity.
How does SHA-256 difficulty adjustment work?
Bitcoin adjusts SHA-256 mining difficulty every 2,016 blocks (approximately every two weeks) to maintain a 10-minute average block time. If the total network hashrate increases, difficulty increases proportionally so blocks are not found faster than target. Bitcoin Cash uses a different difficulty adjustment algorithm (DAA) that recalculates every block, making it more responsive to hashrate changes.