TL;DR
- Google requires all its authentication services to be migrated to quantum-resistant cryptography by 2029
- Around 7 million BTC — an estimated 30–40 percent of all bitcoin — could be vulnerable to quantum attacks
- Bitcoin Improvement Proposal 360 (BIP 360) is the most concrete proposed solution, but no consensus has been reached
- Ethereum has been working on quantum-proofing for eight years; Bitcoin has yet to present an official plan
Google puts the industry under pressure
Google has announced an internal deadline: by 2029, all the company's authentication services must be migrated to cryptographic algorithms that can withstand attacks from quantum computers. The decision is justified by rapid developments in quantum hardware and improved error correction, according to CoinDesk.
The deadline is not just an internal IT measure. It sends a clear signal to the entire technology industry — including the crypto community — that the transition to post-quantum cryptography (PQC) is no longer a hypothetical future scenario, but a concrete engineering challenge with a time limit.
Ethereum has been building towards this goal for eight years. Bitcoin has remained silent so far.
Quantum computing is no longer science fiction — it's engineering.
What exactly is the threat?
Bitcoin's security rests on two cryptographic pillars: elliptic curve cryptography (ECC) for digital signatures, and SHA-256 for hashing and proof-of-work. The problem is that Shor's algorithm, run on a sufficiently powerful quantum machine, can theoretically break ECC — thereby making it possible to derive private keys from public keys exposed on-chain.
Alex Pruden, CEO of Project Eleven — a company specializing in quantum risk in digital assets — describes the situation as a gradual engineering progression towards a cryptographically relevant quantum machine (CRQC) on the order of one million physical qubits.
Quantum computing researcher Scott Aaronson from StarkWare is even more direct: «The time to start thinking about this is now. An even better time would have been yesterday.»
BIP 360 — the most concrete answer so far
Bitcoin Improvement Proposal 360, drafted by Hunter Beast, Ethan Heilman, and Isabel Foxen Duke, introduces a new transaction type that enables the use of quantum-resistant signatures. The proposal builds on Taproot's architecture but eliminates a central vulnerability by no longer exposing public keys on-chain.
The proposal does not require a hard fork and is designed to function as SegWit version 3, with addresses starting with «bc1r». BTQ Technologies has already rolled out a working implementation on its Bitcoin Quantum testnet v0.3.0.
Ethan Heilman informed CoinDesk that BIP 360 has received more comments than any other BIP in history — a sign that the developer community is engaged, even if consensus is far off.
The most relevant algorithm in the Bitcoin context is SPHINCS+ — now standardized by NIST as SLH-DSA (FIPS 205). The advantage is that its security relies solely on hash functions, which are already a fundamental component of Bitcoin. The disadvantage is large signatures, which would burden the network's throughput capacity.
Governance without central leadership — Bitcoin's dilemma
Where Google can set an internal deadline and implement it, Bitcoin lacks a similar mechanism. Protocol changes require broad consensus among developers, miners, node operators, wallet developers, and users — a process that is «slow by design».
Prominent Bitcoiner Nic Carter has publicly criticized what he calls Bitcoin's approach to coordinated protocol upgrades as «worst in class» compared to Ethereum.
At the same time, developers like Matt Corallo reject the notion that Bitcoin core developers are ignoring the problem: «Yes, developers are working on quantum-proofing. I can point to many who are working on this,» says Corallo, according to CoinDesk.
One of the hottest internal debates concerns what should happen to bitcoin in older, vulnerable address formats that do not migrate in time. Jameson Lopp has formalized a proposal to set a «flag day» where older signatures are invalidated — which would effectively make unmigrated funds inaccessible. Critics call this confiscatory. Proponents argue it is necessary to protect the network's integrity.
What happens next?
NIST plans to decommission quantum-vulnerable algorithms from its standards by 2035, with requirements for much earlier transition for high-risk applications. Google's self-imposed 2029 deadline further compresses that leeway for actors who wish to mirror industry best practices.
For Bitcoin, this means that BIP 360 and related proposals need to mature from theoretical discussions to an actual consensus process — and within a timeframe now clearly delimited by actors outside the blockchain itself.
