A future quantum computer could potentially break the cryptography that protects some Bitcoin wallets, but the threat remains hypothetical and no machine capable of carrying out such an attack exists today. The crypto industry is nevertheless working on ways to reduce the risk, with recent developments spanning transaction workarounds, possible Bitcoin protocol changes and new custody safeguards.
Why quantum computing matters for Bitcoin
Bitcoin wallets rely on elliptic-curve cryptography, a system that connects a private key with a corresponding public key. Under current computing capabilities, deriving the private key from the public key is considered impractical. A sufficiently powerful quantum computer using Shor’s algorithm could theoretically change that balance by recovering the private key, creating a valid signature and taking control of the funds.
The hypothetical point at which such a machine becomes capable of attacking Bitcoin is commonly called “Q-Day.” No quantum computer can perform that task today, and estimates for when the technology might become capable vary substantially. However, the range of expected timelines has continued to tighten, encouraging researchers, developers and custodians to prepare before an operational threat appears.
According to Decrypt, three broad approaches were in focus this week. They do not represent a completed solution, and none of the developments reported this week makes Bitcoin quantum-safe by itself. Instead, they show the industry beginning to address the practical cost and implementation questions surrounding the problem.
A cheaper workaround under existing rules
The first approach is to create quantum-resistant transactions without changing Bitcoin’s current rules. StarkWare, which mined the first quantum-safe Bitcoin transaction on mainnet last month, said an open competition had reduced the estimated cost of producing such a transaction from about $320 to approximately $67 in one week. Artificial-intelligence models were at the top of the competition’s rankings.
The lower cost is significant for research and experimentation, but it does not amount to a full fix. StarkWare describes the method as a workaround. The transactions are nonstandard, meaning they do not operate as a normal Bitcoin transaction under the network’s established conventions. They also protect only coins whose public key has not already been exposed.
That limitation matters because the proposed defense is not a universal shield for every Bitcoin wallet. It is instead a way to make certain transactions resistant to the relevant quantum attack while the broader ecosystem considers a more permanent change.
The long-term protocol option
The second path would involve changing Bitcoin itself so that it supports post-quantum digital signatures. These signatures are designed to withstand attacks from quantum computers, rather than relying on the cryptographic assumptions used by Bitcoin today.
A protocol upgrade would be a more durable answer than an isolated transaction workaround, but it would also be much harder to deliver. Bitcoin’s governance is decentralized, so changes must be designed, reviewed, tested and deployed through a process involving the wider community. The source material says such upgrades can take years and that Bitcoin participants have only recently begun engaging seriously with the quantum issue.
A soft fork is one possible route mentioned in the reporting. StarkWare still views that kind of protocol-level change as the better long-term answer, although no such upgrade was completed this week.
Custody defenses and the privacy connection
The third area of work is the custody layer, where exchanges and other institutions safeguard assets for customers. Coinbase’s head of cryptography outlined a post-quantum custody system for the exchange, which safeguards roughly $250 billion in assets. The design is intended to adapt to whichever signature scheme Bitcoin eventually adopts.
The plan also includes a hardware fallback in case the selected post-quantum standard does not work with the key-splitting techniques that custodians currently use. This reflects a practical concern: institutions must protect assets during the transition, even before the network settles on a final cryptographic standard.
Privacy research is developing alongside the quantum effort. The cryptographic tools being considered for quantum resistance overlap with work designed to make Bitcoin transactions more private. Researchers also published a separate “Zcash-style” design for shielded Bitcoin transfers this week. That design is related to the broader research direction but does not, on its own, make Bitcoin resistant to quantum attacks.
Moneyiar market picture
Moneyiar data recorded at 22:04 on September 25, 2026, showed Bitcoin at $83,820.0482, down 0.61% over 24 hours but up 3.20% over seven days. Quant was priced at $97.1850, with a 24-hour gain of 8.56% and a seven-day increase of 53.02%.
Akash Network stood at $0.690860, up 0.29% over 24 hours and 25.09% over seven days. AI Rig Complex was at $0.0712835, down 2.55% over 24 hours and up 0.32% over the week. These figures are Moneyiar market data at the stated time.
The immediate conclusion from this week’s quantum developments is limited but important: Q-Day remains hypothetical, and no reported measure has independently solved Bitcoin’s quantum problem. The work is moving from theory toward logistics—lowering the cost of defensive techniques, considering how Bitcoin might change and planning for institutional custody during a future transition.
