Market Update: Why the new Google paper is reigniting the quantum debate A new research paper from Google has attracted considerable attention in the crypto world. The reason: Google concludes that future quantum computers could attack the cryptography of Bitcoin and other blockchains with significantly less effort than previously thought. At the same time, Google has announced its intention to transition internally to post-quantum cryptographic methods by 2029. For the crypto sector, this clearly signals that quantum resistance is becoming a concrete goal. Why the Google paper is attracting attention nowIt is not an imminent attack that makes the Google paper relevant, but rather the new dimension of its estimates. Google assumes that future quantum computers would require significantly fewer logical and therefore physical qubits to attack the cryptography of many blockchains than previously thought. The research team estimates a reduction in resource requirements of around 20-fold compared to earlier assumptions. For the crypto industry, this means one thing above all: the time available to prepare for quantum-resistant solutions may be shorter than previously assumed. Why there is no immediate threat yetNevertheless, it would be premature to speak of an imminent threat to Bitcoin & Co. The Google paper is a theoretical research result and does not demonstrate that such an attack would be practically feasible today. Google itself refers to “future quantum computers” and emphasises that transitioning to post-quantum cryptographic methods takes time. But that is precisely why the need for action is already growing, even though the quantum computer required for this does not yet exist. Where the specific risk lies for Bitcoin and other blockchainsIt is important to place the risk in the correct context. A quantum computer would not simply crack the Bitcoin blockchain as a whole. Neither the fixed upper limit of 21 million bitcoin nor the proof-of-work mechanism would be directly undermined as a result. The greatest risk concerns coins where the public key is visible. It is precisely these public keys that could theoretically be attacked using Shor’s algorithm.For Bitcoin, this primarily affects very old holdings from early address and script formats – in particular earlier Pay-to-Public-Key structures, where the public key was directly visible on-chain. More modern formats initially conceal the public key behind a hash and are therefore better protected as long as the coins remain unspent. The situation is different for Solana: there, the public key of a keypair is used as the account address. This demonstrates that the quantum debate does not concern Bitcoin alone, but that different blockchains present very different attack surfaces.Frequently mentioned in this context are very early bitcoin holdings that have remained untouched for years and are largely attributed to Satoshi Nakamoto. The official post-quantum page from the Ethereum ecosystem explicitly notes that around five per cent of Bitcoin’s supply is associated with early address formats widely considered abandoned – including Satoshi’s holdings of approximately 1.1 million BTC. Even if this issue remains politically and technically sensitive, it illustrates why the migration of old holdings is likely to become a central topic.Why public blockchains must act nowThe challenge is particularly significant for public blockchains. A company such as Google can establish a migration plan internally and implement it centrally. Open networks like Bitcoin must coordinate such a transition through technical proposals, testing, community debate, and broad consensus. This makes the process slower and more demanding. All the more important, then, to define concrete plans at an early stage.At Ethereum, this process is already more visibly institutionalised. The official post-quantum page from within the Ethereum Foundation’s ecosystem describes a multi-year roadmap spanning several protocol layers. Based on current assessments, L1 protocol upgrades could be completed by 2029, whilst the full migration of the execution layer is expected to take further years beyond that. This is not proof that Ethereum has already resolved the issue. It does, however, demonstrate that the topic is already being addressed there with a concrete structure and a clear timeframe. ConclusionThe new Google paper is not a warning of an imminent attack. It is, however, a clear wake-up call. Research into quantum computers is advancing rapidly. Bitcoin and other public blockchains still have time – but that time should be used. Quantum-resistant security does not emerge overnight; it requires timely technical preparation, clear roadmaps, and broad coordination within the respective networks. Important legal informationThis publication is intended for information and marketing purposes only, and does not constitute investment advice or a specific individual investment recommendation. It is not a sales prospectus and does not constitute a request, an offer, or a recommendation to buy or sell investment instruments or investment services, or to engage in any other transaction. Maerki Baumann & Co. AG does not provide legal or tax advice. Investors are therefore advised to obtain independent legal or tax advice concerning the suitability of such investments, since their tax treatment depends on the personal circumstances of the investor in question and is subject to change at any time. Maerki Baumann & Co. AG holds a Swiss banking licence issued by the Financial Market Supervisory Authority (FINMA). This publication is expressly not intended for persons domiciled in Germany or so-called U.S. persons. Editorial deadline: 6 April 2026Maerki Baumann & Co. AGDreikönigstrasse 6, CH-8002 ZurichT +41 44 286 25 25, info@maerki-baumann.chwww.maerki-baumann.ch