Algorand Surges 50% After Google Research Flags Quantum Threat to Bitcoin and Ethereum

Google Quantum AI published research in April 2026 warning that a sufficiently powerful quantum computer could crack Bitcoin's Elliptic Curve Digital Signature Algorithm cryptography in under nine minutes, one minute faster than Bitcoin's average block settlement time. The research identified approximately 6.5 million bitcoin worth hundreds of billions of dollars sitting in vulnerable addresses, including 1.7 million BTC in old Pay-to-public key addresses used by Satoshi Nakamoto and early miners, as well as Taproot addresses activated in 2021. Google's paper highlighted Algorand as a live example of post-quantum cryptography implementation, triggering a 50% surge in Algorand's token price. Bitcoin developers have proposed multiple solutions including BIP 360's Pay-to-Merkle-Root format, Tadge Dryja's commit/reveal scheme, and Hunter Beast's Hourglass V2, though these proposals face challenges including SPHINCS+ signatures expanding from 64 bytes to 8 kilobytes and difficulty protecting already-exposed coins.

Google's quantum computing threat to Bitcoin cryptography

• ▪The paper was submitted to arXiv on March 30, 2026, and Google’s research post was published on March 31.
• ▪Some analysts believe a quantum computer threat to Bitcoin could become a reality by 2029.

Technical vulnerabilities in Bitcoin's security model

• ▪Roughly 1.7 million BTC sits in old Pay-to-public key (P2PK) addresses including Satoshi Nakamoto's coins.
• ▪Pay-to-public key (P2PK) addresses used by Satoshi Nakamoto and early miners are vulnerable to long exposure quantum attacks.
• ▪About 6.5 million bitcoin tokens worth hundreds of billions of dollars sit in addresses a quantum computer could directly target.
• ▪Taproot (P2TR) address format activated in 2021 is vulnerable to long exposure quantum attacks.

Proposed quantum-resistance solutions and upgrades

• ▪Developer Hunter Beast proposed Hourglass V2 to limit spending of exposed bitcoins to one bitcoin per block.
• ▪Hourglass V2 targets roughly 1.7 million BTC held in older already-exposed addresses vulnerable to quantum attacks.
• ▪Current bitcoin signatures are 64 bytes while SLH-DSA signatures are 8 kilobytes or more in size.
• ▪Bitcoin Improvement Proposal (BIP) 360 protects only new coins going forward and does not address the 1.7 million BTC already sitting in old exposed addresses.
• ▪Bitcoin Improvement Proposal (BIP) 360 introduces a new output type called Pay-to-Merkle-Root (P2MR) that removes the public key permanently embedded on-chain.
• ▪SPHINCS+ was standardized by the National Institute of Standards and Technology (NIST) in August 2024 as FIPS 205 (SLH-DSA).

Perspective of Algorand

• ▪Algorand's token price surged 50% following the Google Quantum AI research publication.

Perspective of Bitcoin developers and protocol maintainers

• ▪Bitcoin Improvement Proposal (BIP) 360 introduces Pay-to-Merkle-Root (P2MR) to remove public keys permanently embedded on-chain.

Perspective of Holders of bitcoin in vulnerable addresses

• ▪Satoshi Nakamoto's bitcoin holdings sit in Pay-to-public key (P2PK) addresses vulnerable to quantum attacks.
• ▪Hourglass V2 targets roughly 1.7 million BTC held in older already-exposed addresses vulnerable to quantum attacks.

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