Crypto's Inability To Stop Hacks Today Bodes Poorly for Quantum Readiness Tomorrow: Experts

That struggle was exposed again on 19 Jul, when an attacker used a flash loan to drain about $1.66mn from Allbridge Core's Solana liquidity pools. Experts said such incidents are a warning about the industry's readiness for a broader security migration.

The attacker stole 1.12mn USDC and 539,000 USDT in a single transaction on 19 Jul, according to Allbridge. User wallets and private keys were not affected, but liquidity providers bore the losses. Allbridge Core's total value locked fell to $11.11mn after the attack from about $20mn a day earlier, according to DeFiLlama.

The exploit relied on a flash loan, a tool attackers can use to amplify weaknesses in a protocol's pricing, accounting or smart-contract design. Flash loans have featured in at least eight publicly reported crypto exploits in 2026, according to a Sandmark review, although they are usually the mechanism used to execute an attack rather than the underlying vulnerability.

Quantum computing poses a technologically much more sophisticated and systemic kind of risk than the routine exploits that continue to plague the industry. Sufficiently powerful machines could eventually break the cryptography used to authorise blockchain transactions, forcing networks to adopt new security standards.

Experts said the persistence of familiar and preventable exploits raises a broader question: whether an industry still struggling with known vulnerabilities is ready to carry out a much more complex transition to quantum-resistant systems.

Known attacks raise readiness questions

"The industry is not realistically ready for a full quantum-security transition today," Yuannan Yang, auditor partner at blockchain security firm CertiK, told Sandmark.

Yang explained that flash-loan attacks are already understood and can be tested today, making them a useful measure of the industry's wider security readiness. "If protocols still fail under those conditions, it is risky to assume they are operationally ready for a much broader migration," he said. 

Those concerns come amid continued losses across the industry. CertiK noted $1.32bn in losses across 344 security incidents during the first half of 2026.

Code vulnerabilities were the most common, accounting for 204 incidents and $151.6mn in losses. Phishing followed with 63 incidents and $366.3mn stolen, while wallet compromises caused the largest losses, totalling $444.5mn across 33 incidents.

Quantum upgrade could take years

No public quantum computer can currently break the signatures used by major blockchains, Yang said. However, experts say that developers should start preparing because moving to quantum-resistant systems could take years.

"The risk is not urgent in the sense that production blockchains are being broken by quantum computers today," Yang said. "It is urgent in the sense that migration will take years and should not begin during a crisis."

Edward Johnson, chief product officer at blockchain network Autheo, echoed Yang's sentiment and added that developers should begin using post-quantum algorithms standardized by the National Institute of Standards and Technology.

He said developers should design systems with replaceable cryptography, allowing security standards to be upgraded without rebuilding the underlying product.

Johnson further warned about "harvest now, decrypt later," in which attackers collect encrypted data today in the hope of decrypting it once more powerful quantum computers become available.

"There's no retroactive fix. There's also a concrete deadline forcing the issue in regulated environments," Johnson said. "FIPS 140-2 validation goes to Historical status with NIST this September. After that, only FIPS 140-3-validated crypto gets accepted for new federal procurement. That's not a distant milestone."

Transitional friction

Yang explained that the Bitcoin, Ethereum and Solana blockchains – the heavy hitters of crypto – have not completed a full move to quantum-resistant cryptography. However, that transition itself could also create a new set of security problems.

Many systems are expected to use both existing and post-quantum cryptography during the transition, adding more code that developers must secure.

"Post-quantum signatures can be much larger and can impose different verification, bandwidth, transaction-size, and integration costs compared with today's elliptic-curve signatures," Yang said. "That can affect fees, blockspace, bandwidth, mempool behaviour, smart-contract gas costs, light clients, hardware wallets, and high-throughput chain designs."

Yang added that networks should move gradually by testing quantum-resistant systems, using both old and new cryptography where needed, auditing the changes, and preparing backup plans before rolling them out more broadly.

"Key rotation at scale, under a deadline, run by teams doing it for the first time, is exactly the kind of high-pressure change that produces mistakes," Johnson said. "The migration itself has to be treated as a security-critical project, not a dependency bump."