Bitcoin's quantum debate just moved from paper to mainnet.
Transaction 305a24ff...ab07 sits in block 964,199. It's a 1,321-vbyte spend built with Quantum Safe Bitcoin (QSB), a research construction from Avihu Levy and Tom Giladi that uses bitcoin's existing Script rules to protect an output under hash-based assumptions instead of relying on the hardness of secp256k1.
No soft fork. No new opcode. A miner accepted the transaction and bitcoin validated it under the rules every node already enforces.
The construction uses a HORS-like one-time signature and a hash-to-signature puzzle inside legacy Script. ECDSA and OP_CHECKSIG still appear in the machinery because they're tools available to Script, but the security claim rests on hash preimage resistance rather than the elliptic-curve assumption a quantum computer would attack.
There are limits. The transaction was non-standard under default relay policy and reached a miner through MARA's Slipstream service. It protects bitcoin intentionally committed to this unusual script. It doesn't reach backward and protect every exposed public key on the UTXO set.
It doesn't give wallets a usable address format, recovery flow, multisig policy, derivation standard, or migration path. And it doesn't answer what happens to coins that never move before a capable quantum machine arrives.
Levy called it a "research quirk", which is exactly right. The design crossed the line from a paper into consensus-valid bitcoin. That shouldn't be confused with a ready-made path to post-quantum security.
Multiple teams are working on the problem. BIP 360 continues to develop a soft-fork path. Hash-based schemes are being actively benchmarked. Material progress is being made without anyone panic-shipping a consensus change.
The alarmists can turn the volume down. The work is happening.
Transaction 305a24ff...ab07 sits in block 964,199. It's a 1,321-vbyte spend built with Quantum Safe Bitcoin (QSB), a research construction from Avihu Levy and Tom Giladi that uses bitcoin's existing Script rules to protect an output under hash-based assumptions instead of relying on the hardness of secp256k1.
No soft fork. No new opcode. A miner accepted the transaction and bitcoin validated it under the rules every node already enforces.
The construction uses a HORS-like one-time signature and a hash-to-signature puzzle inside legacy Script. ECDSA and OP_CHECKSIG still appear in the machinery because they're tools available to Script, but the security claim rests on hash preimage resistance rather than the elliptic-curve assumption a quantum computer would attack.
There are limits. The transaction was non-standard under default relay policy and reached a miner through MARA's Slipstream service. It protects bitcoin intentionally committed to this unusual script. It doesn't reach backward and protect every exposed public key on the UTXO set.
It doesn't give wallets a usable address format, recovery flow, multisig policy, derivation standard, or migration path. And it doesn't answer what happens to coins that never move before a capable quantum machine arrives.
Levy called it a "research quirk", which is exactly right. The design crossed the line from a paper into consensus-valid bitcoin. That shouldn't be confused with a ready-made path to post-quantum security.
Multiple teams are working on the problem. BIP 360 continues to develop a soft-fork path. Hash-based schemes are being actively benchmarked. Material progress is being made without anyone panic-shipping a consensus change.
The alarmists can turn the volume down. The work is happening.
21❤️4👍2
