A Long Game Project lab
The Freeze of Keys
If someone could forge Bitcoin’s signatures, what would happen? Would people move their coins to safety faster than the forgers could take them? And would freezing the coins nobody moves save Bitcoin or split it in two?
Report 010 · Dr Dan Epstein · version 0.8 · signed 14 October 2026
A Strategy Soup Scenario What is an exercised scenario?
TLDR
Bitcoin coins are protected by a secret number. For many coins, the matching public number is already visible. If someone could work out the secret from it, they could forge the owner’s signature and spend those coins: between a fifth and a half of all bitcoin.
We simulated the two years after someone proves they can do it. Old coins whose owners are dead or lost their keys were stolen far more often than frozen. A freeze is a change to Bitcoin’s rules that stops anyone spending those coins. It takes months to switch on, so announcing one early barely cut theft and made it far more likely Bitcoin would split in two.
In 57% of 300 simulated worlds, forgers took the old coins before a freeze could start.
How the simulation works
The simulation covers March 2028 to February 2030 in ten turns. Those dates are for the story, not a forecast. It has six made-up players: the forgers, the people who maintain Bitcoin’s software, a second blockchain’s developers, a big exchange, the big holders and governments.
Each turn, each player picks one move, and chance decides most outcomes. Holders can move coins to safety or sell. Selling drags down the market for every holder. The maintainers can release a fix, such as a safer kind of address, or a freeze, but Bitcoin has no owner, so a change takes about three months to switch on. If part of the network refuses it, Bitcoin splits in two.
We tried four setups for the forgers:
- 1They announce the forgery, then steal.
- 2They steal quietly.
- 3They warn the maintainers and never steal, but someone copies their method.
- 4The forgers choose their own course.
Fixed rules played each of the first three setups 300 times. In eight more plays, two per setup, the other five players chose their own moves, and the forgers did too in setup 4.
What happened
- When the forgers announced first, they took old coins before a freeze could start, three months in, in 57 of every 100 plays, and before any freeze in 67. A freeze came first in 6, and neither happened in 27. Quiet forgers took them before any freeze in 83.
- Coins with living owners were stolen too, in about half the plays.
- A freeze announced in week two took three months to switch on. When the forgers announced first, it cut theft of any kind only from 89 to 85 of every 100 plays, and raised the chance of a split from 18 to 49.
- In those eight plays the holders never sold. They moved their coins to safety.
- The maintainers released every fix in the first weeks, and once a freeze, which failed on its chance when it came due.
- The forgers who chose their own course took old coins before any freeze could come. “The window is closing.”
Announcing a freeze early made a split far more likely.
What it means
Owners who move their coins in time can protect them.
What it cannot tell you
Nobody can forge Bitcoin signatures today. The odds, delays and market effects are our estimates. The simulation counts thefts, not how many bitcoin each took. The players chose their own moves in only two plays per setup.
The line
Once forgery is public, a freeze comes too late: in most plays the old coins were taken before the freeze could switch on, and rushing it made a split far more likely.