Live from the Bitcoin chain: every block flips a coin, every 6 blocks rolls a die — derived from the block hashes the network mines, not chosen by anyone. Computed in your browser (its own SHA-256/HMAC, no server); anyone recomputes the same. It's the same verifiable-randomness machinery that picks the lottery numbers.
This is a demonstration, not a game. No betting, no money, no stakes — just a transparent example of public, verifiable randomness from the Bitcoin chain.
Coin (one per block): seed = SHA-256(block hash), then the first bit
(MSB-first) of HMAC-SHA-256(seed, "coin:0") — 1 → Heads, 0 → Tails, a fair bit.
Die (one per 6-block window): seed = SHA-256(the 6 block hashes joined)
(like the draw concatenating its 144), then the first byte b < 252 of
HMAC-SHA-256(seed, "dice:0") gives b mod 6 + 1 (bytes 252–255 rejected, so
no modulo bias). There's no input: the chain's blocks drive it, and you can recompute any block or
window yourself. Full spec:
docs/RANDOMNESS.md ↗.
Prefer a terminal? python randomness.py does the same.