The Cryptocurrency Economy Has a Quantum Problem
Digital currencies have become the de facto banking system for the unbanked, the sanctioned, and the stateless; Google's research published today suggests the cryptography holding that system together
Cryptocurrency has a reputation problem. To its critics, it remains a speculative casino for technologists with libertarian convictions and a low appetite for regulatory oversight. To its defenders, it represents the first serious challenge to a global financial architecture that has, for decades, served the wealthy, the connected, and the geopolitically convenient - while leaving everyone else to manage with what remains. Both of these characterisations contain truth. Neither captures what cryptocurrency has actually become.
What it has become is a banking system. Not the banking system - not yet, and perhaps never entirely — but a functional, increasingly indispensable financial infrastructure for populations whom the formal system has failed, abandoned, or actively weaponised against. In Gaza, Tether has become the currency of daily commerce because Israeli correspondent banking has rendered the shekel inaccessible. In Afghanistan, blockchain rails now carry UN World Food Programme disbursements to over a million people because the formal banking sector ceased to exist after 2021. In Myanmar, the opposition National Unity Government adopted stablecoins as legal tender because the military junta controls every other payment channel. In Nigeria, stablecoins have become the primary savings instrument for millions because the naira lost most of its value. In Kenya, they carry remittances that used to cost 8% to move and now cost under 2%.
This transformation did not happen by design. It happened by default - driven not by ideology but by the grinding failure of formal financial systems to serve the populations that need them most. And it has happened at precisely the moment when the architecture of global finance is fragmenting rather than converging: when sanctions regimes multiply, when correspondent banking withdraws from jurisdictions deemed too risky, when the dollar’s dominance becomes an instrument of geopolitical coercion rather than a neutral medium of exchange. In a world where the centralised pillars of global finance are increasingly weaponised against the unbanked, the sanctioned, and the politically inconvenient, decentralised alternatives have graduated from curiosity to necessity.
Against this backdrop, a whitepaper published by Google’s Quantum AI team - co-authored with the Ethereum Foundation’s Justin Drake and Stanford cryptographer Dan Boneh - lands with uncommon weight. Its technical argument is precise: future quantum computers may be able to break the cryptographic foundations of Bitcoin, Ethereum, and virtually every major blockchain using roughly 20 times fewer computational resources than the industry had assumed. The machines capable of doing this do not yet exist. But Google believes they could by the end of the decade, and has set 2029 as its own deadline for migrating its systems to quantum-safe cryptography.
For the crypto-curious investor in London or New York, this is a technical problem with a technical solution: migrate to post-quantum cryptography, accept the costs, and move on. For the Afghan family receiving aid through a blockchain wallet, the Gazan food merchant paying suppliers in Bitcoin, or the Kenyan freelancer whose first international payment arrived in stablecoins, the stakes are of a different order entirely. They are not merely exposed to a cryptographic vulnerability. They are exposed to the collapse of the only financial infrastructure that works for them - and they have no migration pathway, no governance forum, and in most cases no awareness that the threat exists.
This is the storyline: the quantum threat to cryptocurrency is not primarily a story about Bitcoin investors facing portfolio losses. It is a story about the fragility of an emergent financial system that has quietly become one of the most consequential tools of development finance and humanitarian response in the world - and about what happens to that system, and to the people who depend on it, when its cryptographic foundations prove less durable than anyone admitted.
The Technical Problem
The cryptography underpinning Bitcoin, Ethereum, and most major blockchains rests on the 256-bit elliptic curve discrete logarithm problem (ECDLP-256): a mathematical challenge so computationally expensive that today’s computers would require billions of years to solve it. Quantum computers, running Shor’s algorithm, could solve it in minutes — provided the machine has enough physical qubits. The question has always been: how many?
Until today, the consensus answer was: millions, placing the threat comfortably in the mid-2030s or beyond. Google’s whitepaper revises that estimate sharply downward. Its team has compiled two optimised quantum circuits for solving ECDLP-256: one using fewer than 1,200 logical qubits and 90 million Toffoli gates; the other fewer than 1,450 logical qubits and 70 million gates. Both are executable on a superconducting architecture with fewer than 500,000 physical qubits — a roughly 20-fold reduction from prior estimates. Given Google’s own hardware roadmap, the company believes a machine of this scale could exist before 2030.
The practical implications follow directly. A future quantum computer of this specification could theoretically derive a Bitcoin private key in approximately nine minutes once a public key is exposed on-chain. Bitcoin’s average block confirmation time is ten minutes. The paper estimates a 41% probability of a successful attack within that window. In cryptography, a 41% success rate against a signature scheme is not a concerning outlier. It is a broken scheme.
The exposure is already substantial. Google estimates roughly 6.9 million Bitcoin - approximately one-third of the total supply - sit in wallets where public keys have already been permanently exposed on-chain. That includes 1.7 million BTC from the network’s earliest years, among them the coins widely attributed to Satoshi Nakamoto. Part of the exposure is self-inflicted: Bitcoin’s 2021 Taproot upgrade, designed to improve privacy and transaction efficiency, also made public keys visible on-chain by default, removing the hash-based protective layer that older address formats had maintained. An upgrade sold as a privacy improvement inadvertently widened the attack surface.
The threat is not confined to coins at rest. Google’s paper introduces the concept of “on-spend” attacks: a future quantum machine intercepts a live transaction in the mempool, derives the private key from the briefly exposed public key, and redirects the funds before the original transaction confirms. This is explicitly a future attack model, not a present capability. But the paper is clear that the margin of safety is “increasingly narrow.”
Ethereum faces a structurally different and in some respects more acute vulnerability. Google maps five distinct quantum attack vectors against Ethereum, putting more than $100 billion in assets at theoretical risk. Unlike Bitcoin, Ethereum permanently exposes a user’s public key the first time they transact, with no ability to rotate it without abandoning the account. The Ethereum Foundation has already launched a post-quantum migration effort, with a multi-fork upgrade roadmap targeting quantum-resistant cryptography by 2029. Bitcoin has not.
Google’s disclosure method is itself significant. Rather than publishing the actual quantum circuits - which would provide a blueprint for adversaries - the team released a zero-knowledge proof, developed in coordination with the US government, that allows independent verification of the claims without revealing the underlying attack details. This is responsible disclosure applied to a domain where the stakes are systemic. When a company of Google’s capability coordinates with the US government before publishing security research and withholds the technical methodology to prevent weaponisation, it is not being overcautious. It is signalling that what it has found is genuinely dangerous.
The governance problem is harder than the technical one. Centralised systems - banks, military networks, government infrastructure - can push software updates to their users. A decentralised blockchain cannot. Bitcoin’s SegWit upgrade, formally proposed in December 2015, did not activate until August 2017 - nearly two years of community negotiation, miner brinkmanship, and threatened forks. Taproot, proposed in January 2018, activated in November 2021: nearly four years. A post-quantum soft fork would be a far more fundamental change, requiring simultaneous consensus across miners, nodes, exchanges, and custodians worldwide. Bitcoin Improvement Proposal 360, which proposes a quantum-resistant output type by removing Taproot’s vulnerable key-path spending, was merged into the BIPs repository only in February. No nodes have upgraded. No activation timeline exists.
Then there are the assets that cannot be migrated at all. Coins in wallets whose private keys have been lost - including Satoshi Nakamoto’s estimated 1.1 million BTC - cannot voluntarily move to quantum-safe addresses. They will sit there, permanently exposed, until a machine powerful enough to reach them arrives. The Google paper proposes a “digital salvage” framework, drawing on maritime salvage law, as one possible governance response. That conversation has not yet begun.
The Deeper Stakes: Finance For The Fragmented World
The technical argument above describes a universal cryptographic vulnerability. But to treat it purely as a technical problem is to miss the more consequential story - one that concerns not the mechanics of elliptic curves but the architecture of a financial system that is quietly reshaping how money moves across the world’s most unstable and excluded spaces.
The formal global financial system was built on an assumption of convergence: that trade liberalisation, capital mobility, and deepening multilateral institutions would gradually extend its benefits to everyone. That assumption is under serious strain. Sanctions regimes have expanded dramatically since 2014, with the US and EU deploying financial exclusion as a primary instrument of foreign policy. Global banks have responded by withdrawing correspondent banking relationships from dozens of jurisdictions - a process known as de-risking - leaving entire countries effectively cut off from the dollar-denominated system. The weaponisation of SWIFT against Russia following the 2022 invasion of Ukraine demonstrated that access to the global payments system is now a geopolitical lever. For countries and populations on the wrong side of that lever, the question of what replaces it is not academic.
Cryptocurrency has begun to provide an answer - imperfect, unregulated, often dangerous, but functional in ways that the formal system is not. The evidence spans three continents and has moved well beyond the theoretical.
In Afghanistan, the collapse of formal banking following the Taliban’s 2021 takeover left 97% of the population below the poverty line and the humanitarian system without a payment channel. The answer came from the blockchain. Mercy Corps’ HesabPay platform, built on Algorand, reached over one million Afghans in 2025, distributing cash assistance from the UN World Food Programme, UNHCR, and the World Bank directly to mobile wallets. A pilot in Paktia province achieved a 29% reduction in delivery costs and cut payment time by ten hours compared to hawala agents — the informal money transfer networks that had previously been the only available channel. This is not a proof of concept. It is operational infrastructure serving over a million people.
In Gaza, the financial system has been destroyed by war and political siege simultaneously. With only two of Gaza’s 94 ATMs still functional as of early 2025, physical banknotes too degraded to use, and Israeli and international banks blocking transfers even from humanitarian donors citing counter-terrorism compliance, USDT has become the currency of daily life. Food merchants pay foreign suppliers in it. Aid organisations transfer it directly to families. “Donations simply couldn’t reach Gaza without cryptocurrencies,” one independent organiser noted. The Atlantic Council has described Palestinian financial agency as the missing piece in most reconstruction plans - and has identified crypto as the de facto backbone of what financial agency remains.
In Myanmar, the National Unity Government formally adopted Tether as legal tender in territories under its control - not ideology but survival, against a junta that controls the central bank and has overseen a kyat losing roughly 75% of its value since the 2021 coup. When a 7.7 magnitude earthquake struck in March 2025, NUGPay became the primary channel for humanitarian assistance to regions the junta had blocked from receiving traditional aid. In Bangladesh, 3.1 million users depend on stablecoin rails as the de facto payment mechanism for 650,000 freelancers who have no other reliable way to receive international income under a comprehensive crypto ban.
The African picture is structural rather than crisis-specific. Nigeria ranks second globally on Chainalysis’s crypto adoption index. The continent received $90.2 billion in remittances in 2023, with traditional corridors charging an average of 8% - fees that consume a significant share of household income for diaspora-dependent families. Stablecoin remittances have reduced those costs by roughly 60%. Stablecoins now account for 43% of all crypto transaction volume in Sub-Saharan Africa - not speculation-driven volume but the daily commerce of populations that are 57% unbanked and have found in mobile-native digital currencies the banking access that formal institutions have not provided. A Mercy Corps pilot in Kenya found that stablecoin micropayments reduced freelancer transaction fees from 29% to 2%, with users saving more and accessing earnings faster - without requiring a bank account.
The WFP’s Building Blocks platform has delivered over $325 million to more than a million refugees since 2017 through blockchain rails in Jordan and Bangladesh. UNHCR delivers emergency funds to displaced families via stablecoin wallets in minutes, with no bank account required. These are not edge cases at the margins of humanitarian innovation. They are operational systems, at scale, doing work that the formal financial system cannot or will not do.
It is worth acknowledging the darker dimension. The same stablecoin rails that carry Rohingya remittances to Cox’s Bazar also carry the proceeds of Myanmar’s Shan State scam compounds. The Tether-on-Tron infrastructure that enables Bangladeshi freelancers to receive international payments also enables pig-butchering fraud networks and money laundering through Lao casino compounds. A loss of confidence in ECDLP-based stablecoins would fall on both the legitimate and the criminal economy simultaneously. There is a perverse case that quantum disruption could accelerate the demise of the corridor’s scam economy - precisely because criminal networks lack the institutional capacity and incentive to migrate to quantum-safe alternatives. But the same disruption would fall with equal force on populations with no alternative at all, and no awareness that the threat exists.
The Asymmetry Of Risk
The quantum threat to cryptocurrency is, in theory, a soluble problem. Post-quantum cryptography is a mature field. NIST has standardised quantum-resistant algorithms. Google has set its migration deadline. Ethereum has a roadmap. The mathematics is understood and the solutions exist.
The problem is not mathematical. It is political and structural. In developed economies, the governance infrastructure to manage a compulsory migration exists: regulators can mandate timelines, exchanges can be required to comply, custodians can be audited. The process will be contentious and expensive, but it can be forced through. For the decentralised communities governing Bitcoin and most major blockchains, no such mechanism exists. Protocol changes require consensus among parties with divergent interests - miners, node operators, exchanges, developers - and that consensus has historically taken years to achieve for upgrades far less complex than a full cryptographic overhaul.
For the populations described above, the asymmetry of risk is acute. The Gazan food merchant who has come to depend on USDT cannot participate in a Bitcoin governance debate. The Afghan family receiving aid through HesabPay cannot request a software update. The Kenyan freelancer receiving her first international payment in stablecoins has no voice in the Ethereum Foundation’s migration roadmap. These people are exposed to the same cryptographic vulnerability as every other user of ECDLP-based systems - but they have no institutional backstop, no regulatory protection, and no migration pathway. If the quantum machine arrives before the protocol upgrades, they lose everything they have stored in it, with no recourse.
There is an additional layer of exposure that the technical literature rarely addresses. Many of the populations most dependent on cryptocurrency are also the most politically exposed. The NUG’s financial infrastructure in Myanmar, the diaspora remittance channels serving communities in conflict zones, the aid payment systems operating under Taliban-controlled territory - these are not merely financial systems. They are, in some cases, the financial nervous system of political resistance movements and the primary channel through which civil society operates in the absence of a functional state. A quantum attack on this infrastructure, whether by a hostile state actor or a criminal network that acquires the capability first, would not merely destroy financial value. It could fund a junta, collapse a resistance, or cut off an aid operation. The stakes of cryptographic failure in these environments are not measured in lost savings. They are measured in lives.
The Unfinished Promise
Step back from the technical detail and the political complexity, and a larger argument becomes visible. Cryptocurrency was not supposed to be a development finance instrument. It was not designed to serve the Rohingya diaspora, the Afghan aid system, or the Nigerian freelance economy. It was designed, by anarchist-adjacent technologists in the aftermath of the 2008 financial crisis, as a censorship-resistant store of value that could not be confiscated, frozen, or inflated away by governments that had abused their monetary authority.
What has happened in the intervening decade and a half is that this infrastructure - built for ideological reasons by people with no particular interest in development finance - has quietly become the most promising instrument of financial inclusion available to the world’s excluded populations. Not because anyone planned it that way, but because the excluded populations found it useful, and because the formal system kept failing them in ways that left no alternative.
The broader context makes this more rather than less important. The world is not converging toward a single, inclusive financial system. It is fragmenting. The network of correspondent banking relationships that made the dollar system function as a neutral infrastructure is contracting. Sanctions have become a primary foreign policy tool, wielded with increasing aggression and decreasing discrimination. The assumption that globalisation would eventually extend formal financial access to everyone has been replaced by the practical reality that it is doing the opposite - that the fragmentation of the geopolitical order is being reproduced, and amplified, in the architecture of global finance.
In this environment, decentralised finance is not a trend. It is an infrastructure necessity. The billion people who lack reliable access to formal financial systems are not waiting for the IMF to issue a report recommending their inclusion. They have found, in cryptocurrency, a system that works for them - imperfect, volatile, often exploited by criminals, but functional in the specific sense that matters: it moves money across borders, preserves value against inflation, and operates independently of the political actors who have the most to gain from controlling it.
Google’s paper is not merely a warning about elliptic curves. It is a warning about the fragility of this entire edifice. The cryptography holding decentralised finance together is the same cryptography that Google has now shown is more vulnerable than the industry was prepared to admit. The window to replace it is open, but narrowing. And the populations who have the most to lose if it closes without action are the ones with the least power to demand that action be taken.
The cryptocurrency economy has a quantum problem. But at its core, it has a governance problem: the infrastructure that serves the world’s most excluded populations is governed by a technical community that did not build it for them, is not primarily accountable to them, and has historically taken years to agree on changes far simpler than a full cryptographic overhaul. Google has provided the technical warning. Whether the governance follows is a political question - and one that will be answered, one way or another, well before the quantum machines arrive.
The quantum tsunami is still offshore. The sea wall, for those with the institutions to build it, is under construction. For the rest, the warning has arrived. The clock is running.
Rafal Rohozinski is the founder and CEO of Secdev Group, a senior fellow at the Centre for International Governance Innovation (CIGI), and co-chair of the Canadian AI Sovereignty and Innovation Cluster.
The Risk Ahead
SecDev’s geopolitical risk practice - builds on three decades of fieldwork across 120+ countries industrialized into on-demand strategic advantage. The era of treating geopolitical risk as an externality is over. Supply chains now span hostile borders, critical technologies depend on adversarial states, and market access hinges on diplomatic whims. What was once the domain of foreign ministries has become every CEO’s problem. SecDev’s Intelligence as a Service delivers tiered, contract-free engagement: from real-time assessments that move faster than markets to deep-dive analysis that uncovers the networks and contacts buried in geopolitical complexity. The question isn’t whether geopolitical shocks will hit your business - it’s whether you’ll see them coming.
SecDev AI
SecDev AI delivers first-in-class Data as a Service AI solutions combining highly trained models with unique, curated datasets. Our next-generation, precision-built expert systems meet the most demanding requirements. By integrating data curation with advanced machine learning, we provide specialized tools that deliver actionable insights where accuracy and reliability are paramount.