Quantum Computing vs. Bitcoin: Is Your Crypto Fortune at Risk in 2025?

Quantum computers could crack Bitcoin's code—but Wall Street's still betting on hamster wheels.

The Looming Quantum Threat

Supercomputers capable of breaking SHA-256 encryption are no longer sci-fi. IBM's 1,121-qubit Condor processor already exists—and Bitcoin's 256-bit keys might not withstand its brute force.

Why Satoshi Didn't See This Coming

Quantum resistance wasn't baked into Bitcoin's DNA. The blockchain's security relies on math problems classical computers can't solve... but quantum rigs might slice through like a hot wallet through butter.

The Crypto Industry's Contingency Plans

From quantum-secure forks to lattice-based cryptography, developers are racing to future-proof the network. Meanwhile, hedge funds keep trading BTC futures like it's 2021—because nothing motivates innovation like the threat of losing other people's money.

Bottom Line
: Your keys might be quantum-vulnerable, but human greed? That's forever.

In Brief

• ChainCode has calculated that 32.7% of BTC are currently vulnerable.
• 6.36 million bitcoins are currently at risk.
• 103 million utxos representing 4.49 million BTC are vulnerable due to address reuse.

Bitcoin and Cryptography

Recent advances by Google and Microsoft in quantum computing have evolved the consensus. Several BIPs are already on the table to address the threat.

Don’t miss our previous article about BIP-360. You will find plenty of information on the subject there. Today’s article focuses on the exact number of BTC currently vulnerable to the quantum threat. The figures come from the ChainCode Labs report presented by Anthony Milton at the Quantum Bitcoin Summit.

Before the numbers, let’s quickly review the cryptographic mechanisms of bitcoin. Let’s start with bitcoin addresses that are most familiar to us. These addresses are encodings of public keys, hence the term “public key cryptography,” also called “asymmetric cryptography.”

These public keys are created from a private key commonly called the “seed.” That is, the 12 or 24 words generated when creating a wallet. These 12 words actually represent a large 128-bit number (plus a checksum) from which your wallet can derive billions of public keys (Bitcoin addresses).

Nowadays, “public keys” are not really public anymore. As mentioned above, they are hashed using quantum-resistant hashing functions RIPEMD-160 and especially SHA-256. The resulting hash is what we call a “Bitcoin address.”

These addresses are used to build UTXOs (Unspent Transaction Outputs). This technical term refers to “scripts” (a piece of code) that lock an amount of BTC (a number) to a public key.

Each BTC transaction consumes and creates UTXOs simultaneously. There are currently about 170 million UTXOs.

The Unbreakable SHA-256

Wallets therefore do not actually contain bitcoins, but private and public keys. These keys are very large numbers linked by a “one-way” mathematical function. In other words, it is impossible for a classical computer to compute a private key from a public key.

The problem is that quantum computers could achieve this (thanks to Shor’s algorithm). Sharp minds might say: “So what? No problem since we said addresses are encoded with the SHA-256 algorithm which is resistant to quantum computers.”

Absolutely. A public key concealed behind a SHA-256 encoding is safe, no matter what. However, making a transaction necessarily reveals the public key associated with the UTXO being spent.

After this transaction, the public key is known to everyone. Therefore, the address in question should no longer be reused to receive new BTC. Unfortunately, many addresses are reused.

Added to these reused addresses are the addresses of the very first types of UTXOs which were simply public keys without any encoding. This type of script is called P2PK (Pay-to-Public-Key). And finally, the spent P2TR (Pay-to-TAPROOT) UTXOs.

Altogether, ChainCode calculated that 32.7% of BTC are currently vulnerable. That is about 6.36 million bitcoins. Of this total, 69% (103 million UTXOs representing 4.49 million BTC) are vulnerable due to address reuse.

The rest mainly consists of P2PK-type UTXOs (1.87 million BTC), or 8.65% of BTC in circulation. And P2TR UTXOs (0.15 million BTC).

Are Your Bitcoins in Danger?

Yes, if you have reused an address after using it for a transaction.
Yes, if your addresses are of the P2PK type. There is, however, little chance this is the case if you installed your wallet after 2011.

Also yes if you participated in the “ordinals” trend and other inscriptions that mostly use P2TR UTXOs. However, these UTXOs contain very few BTC.

The Project 11 site allows you to check if any of your addresses have been reused. If so, just send those BTC back to yourself, to a new address.

Here is a list of address types resistant to quantum computers (if you don’t reuse them):

• P2PKH addresses (Pay-to-Public-Key-Hash). These addresses always start with “1“. For example:

(34 characters)

• P2SH addresses (Pay-to-Script-Hash). They always start with “3“. For example:

(34 characters)

• P2WPKH (Pay-to-Witness-Public-Key-Hash, SegWit) and P2WSH (Pay-to-Witness-Script-Hash, SegWit) addresses. Both start with “bc1q“. For example:

(42 characters)
(62 characters)

Let’s finish by noting that less than 20% of addresses have been reused. The problem is that they are linked to more than 60% of UTXOs and 22.5% of bitcoins. This is largely due to exchanges often reusing the same addresses.

The reused address containing the most BTC belongs, for example, to Binance, with 249,000 BTC that could be taken by a quantum computer…

Bitcoins linked to reused addresses can easily be moved to new addresses. But according to Anthony Milton’s estimates, about 2 million lost bitcoins will remain vulnerable, notably those of Satoshi Nakamoto.

On this subject, don’t miss our article: Should Satoshi Nakamoto’s Bitcoins Be Erased (before the advent of the quantum computer)?

Maximize your Cointribune experience with our "Read to Earn" program! For every article you read, earn points and access exclusive rewards. Sign up now and start earning benefits.