Migration timelines are central to threat response; faster upgrades reduce risk, while delays could outpace protection measures.

Project Eleven warns that Q-Day—the moment quantum computers can break widely used public-key cryptography—could arrive around 2030, potentially exposing millions of bitcoins.

In The Quantum Threat to Blockchains 2026 Report, the firm outlines a framework to measure progress toward cryptographically relevant quantum computers and to estimate Q-Day.

Estimates suggest up to about 6.9 million Bitcoins could be exposed under certain conditions, a stake worth more than $560 billion at current prices.

Founders Alex Pruden and Conor Deegan note that engineering paths differ by protocol, but all blockchains will need post-quantum signatures across the tech stack.

A multi-layered defense is recommended: adopt quantum-resistant cryptography, test on test networks, and bolster security with multi-signature wallets, cold storage, and stronger transaction verification.

Migration to quantum-resistant cryptography is seen as inevitable for trusted blockchains, yet practical migration is slow and complex due to governance hurdles and the scale of on-chain upgrades.

The broader tech ecosystem is moving toward post-quantum security (web traffic, OpenSSH, Apple devices, NSA timelines), highlighting crypto’s lag behind other sectors.

The immediate risk is limited, but preparation is essential for a secure transition to a quantum era.

Developers and the blockchain community are urged to proactively transition to quantum-resistant infrastructure while preserving network integrity and asset security.

A core finding is that elliptic-curve-based signatures (used by major blockchains) face compatibility challenges and will require redesigns across multiple stack layers, with coordination starting now.

Mosca’s inequality underscores that upgrading too slowly leaves systems exposed once threat levels rise, making timely migration planning urgent.