{
  "title": "Published estimates of quantum-exposed bitcoin, 2025-2026",
  "article": "https://synxcrypto.com/is-bitcoin-quantum-safe-2026.php#exposure",
  "reviewed": "2026-09-23",
  "license": "CC BY 4.0",
  "scope": "Each estimate counts something different; the \"What it counts\" column is part of the figure.",
  "columns": [
    "Source",
    "Estimate",
    "What it counts",
    "Source URL"
  ],
  "rows": [
    [
      "Glassnode, 20 May 2026",
      "6.04M BTC (30.2%): 1.92M structural, 4.12M operational; 1.66M exchange-related",
      "Coins whose public key is visible at rest",
      "https://research.glassnode.com/measuring-bitcoins-quantum-exposed-supply/"
    ],
    [
      "Project 11, cited by Coinbase’s advisory board, Apr 2026; the same figure appears in Google Quantum AI’s March 2026 paper",
      "About 6.9M BTC, including about 1.7M in P2PK; about 1M in eleven addresses",
      "Outputs whose cleartext public key is known",
      "https://arxiv.org/abs/2603.28846"
    ],
    [
      "BIP 361, data as of 1 Mar 2026",
      "Over 34% of all bitcoin",
      "Bitcoin that has revealed a public key on-chain",
      "https://github.com/bitcoin/bips/blob/master/bip-0361.mediawiki"
    ],
    [
      "Chaincode Labs, May 2025",
      "4–10M BTC (20–50%) across published estimates; about 6.26M immediately vulnerable",
      "Exposed keys from script type and address reuse",
      "https://chaincode.com/bitcoin-post-quantum.pdf"
    ],
    [
      "CoinShares, 6 Feb 2026",
      "About 1.6M BTC (8%) in P2PK; only 10,200 BTC in outputs large enough to disrupt the market",
      "Legacy P2PK outputs only",
      "https://coinshares.com/es-en/insights/research-data/quantum-vulnerability-in-bitcoin-a-manageable-risk/"
    ]
  ]
}