{"id":90762,"date":"2025-11-07T12:48:33","date_gmt":"2025-11-07T09:48:33","guid":{"rendered":"https:\/\/forklog.com\/en\/?p=90762"},"modified":"2025-12-04T06:51:58","modified_gmt":"2025-12-04T03:51:58","slug":"secret-harvesters-why-quantum-computers-threaten-bitcoin-privacy","status":"publish","type":"post","link":"https:\/\/forklog.com\/en\/secret-harvesters-why-quantum-computers-threaten-bitcoin-privacy\/","title":{"rendered":"Breaking Bitcoin’s Shield: The Looming Danger of Quantum Computing to Privacy"},"content":{"rendered":"

In September 2025, the US Federal Reserve published<\/a> an analytical paper on the Harvest Now, Decrypt Later (HNDL) strategy. The approach assumes adversaries collect encrypted data today to decrypt it in future with sufficiently powerful quantum computers.<\/p>\n

The authors use Bitcoin as an example and examine what HNDL could mean for blockchains built on traditional cryptography.<\/p>\n

They conclude that even timely adoption of post-quantum cryptography will not shield historical data because blockchains are immutable. Together with representatives of the bitcoin mixer Mixer.Money<\/a>, we outline proactive steps users can take to bolster privacy even after \u201cQ Day\u201d.<\/p>\n

How HNDL works<\/h2>\n

The attack is simple: an adversary copies databases and other protected information. There is no immediate payoff, but once a cryptoanalytically-relevant quantum computer (CRQC) emerges, it can unlock private keys or information tied to transaction histories.<\/p>\n

For Bitcoin, the quantum threat implies a potential break of digital signatures. A sufficiently powerful quantum computer could derive a private key from a public one, opening the door to wallet compromise and transaction-history exposure.<\/p>\n

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\u201cAt first glance, in such a situation privacy looks like the least of concerns. However, the Fed\u2019s research draws attention to the fact that timely deployment of post-quantum cryptography will not protect historical data. Even if users move funds to quantum-resistant addresses, attackers could potentially reveal previously inaccessible data about transactions and links between addresses,\u201d say representatives of Mixer.Money.<\/em><\/p>\n<\/blockquote>\n

The Fed study stresses that, unlike security, privacy lacks a simple fix. Bitcoin\u2019s historical data are exposed to retrospective compromise.<\/p>\n

The vulnerability of Bitcoin addresses<\/h2>\n

There are different types of Bitcoin addresses<\/a>. Their susceptibility to quantum attack depends on when and how the public key becomes visible.<\/p>\n