lotterypuzzle atlas

Bitcoin Puzzle record

Bitcoin Puzzle #81

open · address only

8.1 BTC nominal280 candidate keys

Where it sits on the line

Puzzles #69–#93: search work One column per puzzle; height is the base-2 logarithm of the search steps. Puzzle #81 is highlighted. The line sits at 2^69. #69 · 2^68 #70 · 2^35.5 #71 · 2^70 #72 · 2^71 #73 · 2^72 #74 · 2^73 #75 · 2^38 #76 · 2^75 #77 · 2^76 #78 · 2^77 #79 · 2^78 #80 · 2^40.5 #81 · 2^80 #82 · 2^81 #83 · 2^82 #84 · 2^83 #85 · 2^43 #86 · 2^85 #87 · 2^86 #88 · 2^87 #89 · 2^88 #90 · 2^45.5 #91 · 2^90 #92 · 2^91 #93 · 2^92
  • found
  • open · address only
  • open · public key on chain
  • the line · 269

This puzzle needs about 280 search steps — above the line (269).

No puzzle above the line has been found yet.

Model: range scan. Every candidate key in the interval is hashed and compared with the address.

How the work is estimated

Record

P2PKH address
15qsCm78whspNQFydGJQk5rexzxTQopnHZ
mempool.space Blockstream
HASH160
351e605fac813965951ba433b7c2956bf8ad95ce
Search class
address-only
No public key on record: the only route is to hash candidate keys and compare them with the address (HASH160).
Candidate interval
280 → 281 − 1
start0x100000000000000000000
end0x1ffffffffffffffffffff
Interval size1208925819614629174706176 scalars. Exact BigInt bounds, not a floating estimate.

Snapshot 2 Oct 2026. The reward is the catalog's nominal allocation (N × 0.1 convention from 2023-04-16; earlier spends predate it), not a live balance. A key that matches the address proves the math, not that the coins are still there: check an explorer. Missing fields are omitted, not invented.

Method

Without a catalogued public key the work is sequential HASH160 comparison across the interval, so it grows with the interval size.