The proof of work · BLAKE2b hash explainedBLAKE2b vs SHA-256
Bitcoin is mined with SHA-256. Since block 961,640 this chain has been mined with BLAKE2b-256, which needs different hardware. This page compares the two hashes and lists the machines that can mine it.
Updated 27 September 2026
BLAKE2b and SHA-256 side by side
| SHA-256 (Bitcoin) | BLAKE2b (this chain) | |
|---|---|---|
| Designed by | NSA, published by NIST in 2001 as part of SHA-2 | Aumasson, Neves, Wilcox-O'Hearn and Winnerlein, 2012; specified in RFC 7693 |
| Built for | 32-bit words | 64-bit words |
| Rounds | 64 | 12 |
| Output | 256 bits | 1 to 64 bytes; this chain uses 256 bits (BLAKE2b-256) |
| How mining uses it | SHA-256 applied twice (SHA-256d) to an 80-byte block header | BLAKE2b-256 over an 80-byte, Sia-style work unit; blocks carry a 164-byte header |
| Known practical attacks | None | None |
| ASICs that mine it | Antminer S19 / S21, Whatsminer and other Bitcoin miners | Siacoin miners: Goldshell SC series, iBeLink BM-S3, Antminer A3 |
Both are sound hashes. For a miner the difference is hardware: an ASIC is a circuit for one function, so a SHA-256 machine cannot hash BLAKE2b, and a BLAKE2b machine cannot hash SHA-256.
What BLAKE2b is
BLAKE2 is a family of hash functions released in 2012 by Jean-Philippe Aumasson, Samuel Neves, Zooko Wilcox-O'Hearn and Christian Winnerlein. It is a faster redesign of BLAKE, one of the five finalists in the SHA-3 competition. BLAKE2b is the version for 64-bit processors; BLAKE2s is for smaller ones.
Outside this chain it is used in the Argon2 password hash, in checksum tools such as b2sum, and in Siacoin's proof of work. Its mixing step is adapted from the ChaCha stream cipher.
Why this chain mines with BLAKE2b
On 30 August 2026, at block 961,640, this chain stopped hashing with SHA-256 and started hashing with BLAKE2b-256. The ledger, the 21 million cap, the halving schedule and the script rules stayed Bitcoin's (what carried over).
Changing the proof of work resets the hardware race. The large SHA-256 farms that dominate Bitcoin mining cannot mine here at all. Most of this chain's hashrate runs DATUM, where the miner's own node builds the block (how mining works here).
Which miners can mine it
Any ASIC built for Siacoin, on stock firmware: the Goldshell SC series (SC Lite, SC Box, SC Box II, SC5 Pro), the iBeLink BM-S3 and BM-S3+, and the Antminer A3. SHA-256 miners can't mine it, and neither can Decred's BLAKE-256 machines.
Before you mine: this chain shares its history with SHA-256 Bitcoin, so never mine to an address that holds real BTC. Why, and what to use instead.
Questions
Is BLAKE2b more secure than SHA-256?
Neither has a known practical attack. SHA-256 has been studied for longer; BLAKE was studied heavily as a SHA-3 finalist, and BLAKE2 builds on it. For mining, what matters is hardware: a machine built for one cannot compute the other.
Can an Antminer S19 mine BLAKE2b?
No. The S19, S21 and Whatsminer series only compute SHA-256, so they cannot produce a valid share on a BLAKE2b chain. You need a BLAKE2b ASIC of the kind built for Siacoin.
Is BLAKE2b the same as Decred's BLAKE-256?
No. Decred uses the original BLAKE-256 with 14 rounds. BLAKE2b is the later redesign with 12 rounds and 64-bit words. The results differ, so Decred and Siacoin ASICs are different machines.
Why do Siacoin ASICs work on this chain?
Siacoin's proof of work is BLAKE2b-256, and pools here hand miners the same 80-byte Sia-style work unit, so Siacoin machines such as the Goldshell SC series, iBeLink BM-S3 and Antminer A3 mine it on stock firmware.