## Quantum Doomsday Clock: How Much Time Is Left for Bitcoin Before 2028?

The quantum threat to Bitcoin already has an expiration date marked on the calendar. According to an online calculator developed by Dr. Richard Carback and entrepreneur Colton Dillion under Postquant Labs and Hadamard Gate Inc., the cryptographically relevant quantum computers (CRQC) could potentially compromise Bitcoin's private keys in approximately two years, specifically by March 8, 2028. The quantum doomsday clock is not speculation; it is a projection based on rigorous calculations suggesting that 1.673 logical qubits would be sufficient to run Shor's algorithm and break the encryption strength of the Bitcoin network.

## **Disagreement Among Expert Community**

However, the 2028 date generates intense disagreements among specialists. Institutions like NIST and the Global Risk Institute place the credible threat in a broader range: between 2028 and 2035. Craig Gidney from Google went further in a 2025 published article, suggesting that the quantum resources needed could be up to 20 times less than estimated to break RSA-2048 encryption, potentially bringing the critical point closer to 2030. Meanwhile, Naoris Protocol's CEO warns of risks even within five years, and the Global Risk Institute projects a 50% chance of a serious threat by 2039, with rapid increases during the 2030s.

In contrast, Adam Back from Blockstream maintains a calmer stance, arguing that there is no visible threat for at least another 20 years. Still, he acknowledges that when quantum advancements materialize, Bitcoin holders will likely need to migrate their funds to quantum-resistant architectures.

## **Which Addresses Are at Risk?**

Old Bitcoin addresses that have already spent funds, such as reused P2PK and P2PKH addresses, become vulnerable because they expose their public keys on the blockchain. These would appear as castles defenseless against immediate quantum attacks. Modern Taproot and segregated witness addresses enjoy greater temporary protection, as only their hash shadows are exposed on the blockchain, giving their owners an additional time margin.

## **The Quantum Race of Tech Giants**

IBM plans to present Quantum Starling, its first fault-tolerant quantum computer, by 2029. Google already sets records with its Willow chip of 105 qubits, turning scenarios that once seemed science fiction into almost present-day facts. This technological acceleration validates the legitimacy of the question: is Bitcoin's cryptographic architecture facing its encounter with the quantum dragon? The doomsday clock advances regardless of skepticism or concern it may generate, and this quantum transformation will redefine security parameters across the entire cryptocurrency industry.