Many are believed to belong to Bitcoin’s pseudonymous creator Satoshi Nakamoto and other owners who have lost their keys, meaning they can never be made safe. According to Project11, a research group tracking the issue, about 5 million more are exposed through address reuse, although most of them are considered active holdings in exchange wallets.
Exchanging quantum-resistant signatures is the easy part, but the fight is over the coins no one moves. One camp argues for a strict deadline, after which the signature systems used today by Bitcoin, ECDSA and Schnorr, will cease to be accepted and any unmigrated coins will become unusable. Leaving them alive, this camp argues, gives a future attacker, potentially a sanctioned state like North Korea, a large enough supply of bitcoins to drive down the price and taint the network’s legitimacy.
The other camp calls this confiscation a violation of the absolute property rights on which Bitcoin was built and warns that it sets a precedent for the subsequent freezing of the coins under government pressure.
Between them are the many proposals that CoinDesk has been tracking over the past couple of months.
Hourglass would limit the number of vulnerable coins that can be spent per block to avoid a supply flood. BIP-361, from developer Jameson Lopp and others, would allow migrated holders to prove their ownership after the cut with a quantum-resistant proof that exposes no keys. PACTs, from Paradigm’s Dan Robinson, would allow homeowners to time-stamp a private claim now and transfer funds later without revealing anything today.
