Google Quantum AI Puts Bitcoin, XRP Encryption at Risk

Google just shifted the timeline on one of crypto’s most debated threats. A new whitepaper from Google Quantum AI, authored by Ryan Babbush, Director of Research for Quantum Algorithms, and Hartmut Neven, VP of Engineering, warns that quantum computers could break the cryptographic layer protecting Bitcoin, XRP, and other major blockchains sooner than the industry had priced in.

The paper, released Monday, puts hard numbers behind the concern. A superconducting quantum machine running fewer than 500,000 physical qubits could crack Bitcoin’s 256-bit elliptic curve encryption in minutes. That figure is roughly a 20-fold drop in the qubit count previously thought necessary to execute the attack.

6.9 Million BTC Sitting Exposed

Approximately 6.9 million Bitcoin are vulnerable to what the paper calls “at-rest attacks.” These are coins held in old Pay-to-Public-Key addresses, where the public key is permanently visible on-chain. About 1.7 million BTC sit in that category specifically.

No transaction needs to happen. A future attacker could silently derive the private key from publicly available blockchain data, with no warning broadcast to the network. That pool includes wallets widely believed to belong to Satoshi Nakamoto. The full whitepaper describes them as a “fixed, multibillion-dollar target” if protocol-level changes do not arrive in time.

The research team built two quantum circuits implementing Shor’s algorithm for ECDLP-256. One uses under 1,200 logical qubits and 90 million Toffoli gates. The other runs under 1,450 logical qubits with 70 million gates. Both fit within timelines consistent with Google’s existing quantum hardware roadmap.

A superconducting quantum computer could derive a Bitcoin private key in approximately 9 minutes. That sits just inside Bitcoin’s average 10-minute block window.

XRP Faces the Same Structural Vulnerability

XRP’s exposure here is not hypothetical. The XRP Ledger, like Bitcoin and Ethereum, uses elliptic curve cryptography as its security foundation. Specifically, ECDSA over the secp256k1 curve secures wallet addresses and transaction signing on the ledger. That is precisely the cryptographic scheme Google’s paper targets.

What makes XRP’s position worth watching is the speed at which value moves through the network. XRP settles transactions in 3 to 5 seconds. In a world where a quantum machine can derive a private key in under 10 minutes, the transaction window provides some buffer. But wallets with exposed public keys, particularly those that have previously signed transactions, carry the same at-rest vulnerability described in the paper.

XRP’s centralized governance structure could actually work in its favor here. Ripple and the XRP Ledger Foundation have a faster decision-making track than fully decentralized protocols. Rolling out post-quantum cryptography updates does not require the same community-wide consensus battles that have historically slowed Bitcoin upgrades. That matters when the Google research team is saying the window to act is shrinking.

The Disclosure Problem Google Had to Solve

Publishing this kind of research carries real risk. Babbush and Neven address that directly in the paper. Sharing too much could hand bad actors a usable blueprint. Sharing nothing lets the vulnerability build without any industry response.

Google’s solution was a zero-knowledge proof, a cryptographic method allowing outside researchers to verify the claims without Google exposing the actual attack circuits. The team also coordinated with the U.S. government before the paper went public. That places this disclosure in line with CERT/CC at Carnegie Mellon, Google’s own Project Zero, and the international standard ISO/IEC 29147:2018.

The paper draws a clear line between responsible science and FUD. Unsubstantiated quantum threat claims can themselves damage confidence in crypto markets. Google’s team argues the zero-knowledge disclosure model is the right way to raise a verified alarm without triggering panic based on unverifiable figures.

The 2029 Window and What Needs to Happen

Google set a 2029 deadline for transitioning its own systems to post-quantum cryptography. That same timeline now carries direct weight for the crypto space. Coinbase, the Stanford Institute for Blockchain Research, and the Ethereum Foundation are listed as partners working toward responsible migration.

Post-quantum cryptography is the proposed fix across the board. Encryption schemes designed to hold up against quantum-scale attacks already exist. Experimental PQC deployments have been tested on otherwise quantum-vulnerable blockchains. The harder problem is getting entire networks to adopt them at protocol level before a capable quantum machine exists.

The paper recommends against reusing or exposing vulnerable wallet addresses as a near-term step. It also raises the possibility of government frameworks for “digital salvage,” treating dormant quantum-exposed coins similarly to unclaimed assets, before they become targets for state actors or organized criminal networks.

Google has been working on post-quantum cryptography since 2016. The new whitepaper is framed not as a prediction of imminent collapse but as a coordinated warning with a verified technical basis. The team states it welcomes further discussion with quantum, security, cryptocurrency, and policy communities on aligning responsible disclosure norms going forward.