TL;DR
- Bitcoin developer Jameson Lopp advocates for freezing approximately 5.6 million BTC that have not moved in over ten years
- The rationale is that quantum computers could give attackers the ability to break the encryption protecting these addresses
- The proposal is controversial and challenges Bitcoin's fundamental principle of immutable ownership
- Bitcoin fell 4.2 percent early on April 15, which, according to Research, partly reflects uncertainty surrounding this debate
Lopp Aims to Halt Quantum Theft with Protocol Intervention
Bitcoin developer Jameson Lopp has once again raised the question that divides the crypto community: what should be done with the enormous amounts of Bitcoin lying untouched in old addresses – and which are potentially vulnerable to future quantum computers?
In his latest post, Lopp argues that it is a better outcome to freeze these funds at the protocol level than to risk malicious actors, armed with quantum computing power, draining them in one swoop, according to CoinDesk.
It is better for the funds to be inaccessible to everyone than for them to fall into the hands of a quantum attacker.
What is the Actual Risk?
The problem relates to Bitcoin's use of elliptic curve cryptography (ECDSA). The quantum algorithm known as Shor's algorithm can in theory break ECDSA, thereby making it possible to derive private keys from exposed public keys.
This is particularly relevant for the earliest Bitcoin addresses of the Pay-to-Public-Key (P2PK) type, where the public key is already visible on the blockchain. According to research, as many as 1.7 million BTC could reside in such addresses – equivalent to about 8 percent of the circulating supply. Adding other vulnerable addresses, the total could approach 2.3 million BTC.
The 5.6 million BTC Lopp refers to are all coins that have not moved in more than ten years – representing about 28 percent of the total supply – and which he considers a systemic risk if quantum technology matures.
Google's own researchers Ryan Babbush and Hartmut Neven have, according to research material, urged all vulnerable crypto communities to migrate to post-quantum cryptography (PQC) “without delay.” Some calculations suggest that a cryptographically relevant quantum computer could emerge as early as 2029.
BIP-360 and BIP-361: The Proposals Behind the Debate
Lopp's proposal is concretized through Bitcoin Improvement Proposals 360 and 361, which he co-authored.
BIP-360 proposes a soft fork that introduces a new transaction type called pay-to-Merkle-root (P2MR). The purpose is to remove the key-based spending path from the Taproot framework – precisely the path that is vulnerable to quantum computation.
BIP-361 builds on this, outlining a phased transition where older addresses with exposed public keys will gradually lose the ability to spend funds, unless owners migrate to new quantum-resistant address types.
Such changes require network-level consensus and will in all likelihood take years to implement, similar to the SegWit and Taproot upgrades.
Strong Opposition from Principled Critics
The proposal has triggered a strong backlash. The core of the criticism is that freezing addresses – even with quantum threats as justification – undermines what Bitcoin's founder promised: immutable, censorship-resistant ownership.
Leo Fan, founder of Cysic and former worker on quantum resistance at Algorand, states, according to research material, that such measures make ownership conditional: having the keys no longer means one can use the funds.
Market analyst Mati Greenspan from Quantum Economics warns in the same material that a protocol intervention, even if it removes a serious tail risk, sets a precedent for future intervention that many will argue is more dangerous than the threat it is meant to avert.
Critics also point out that it is technically challenging to define what is “dormant”: a long-term holder who deliberately does not touch their funds for ten years could suddenly be affected without warning or clear recourse.
Alternative Technical Solutions Exist
Lopp's proposal is not the only path to quantum resistance. StarkWare has presented a scheme called Quantum Safe Bitcoin (QSB) which, according to the company, makes transactions quantum-resistant without requiring a soft fork. The solution is based on hash cryptography instead of ECDSA but is costly and computationally intensive – estimated at between $75 and $200 per transaction – and is therefore described as an emergency measure rather than a permanent solution.
Broader migration frameworks within post-quantum cryptography, such as hash-based signatures (SPHINCS+, XMSS) and lattice-based solutions (CRYSTALS-Dilithium, FALCON), are considered by the research community as mature alternatives – but they require years of development, testing, and global coordination to be integrated into Bitcoin.
The Debate is Far From Over
As of April 15, 2026, this remains an open debate without consensus in the Bitcoin developer community. It is emphasized that none of the mentioned proposals have been adopted or activated, and the timelines for any potential implementation are highly uncertain.
What Lopp's proposal clearly shows is that the quantum question is no longer an abstract future problem but something that now shapes the discussion about Bitcoin's long-term security model at a concrete and technical level.
