What is the Q-Day prize? The Q-Day Prize is a challenge to make the Bitcoin network quantum resista
What is the Q-Day prize?
The Q-Day Prize is a challenge to make the Bitcoin network quantum resistant.
On April 16, 2025, quantum computing-focused company Project 11 announced the “Q-Day Prize,” a competition to break a “toy version” of Bitcoin’s cryptography with a quantum computer. Contestants must complete the Q-Day Prize challenge by April 5, 2026.
Their reward? 1 Bitcoin (BTC).
The “Q” in Q-Day refers to quantum computing, the potential threat to many existing cryptographic security measures.
But can quantum computers break Bitcoin? Let’s find out.
Quantum computing and the threat to Bitcoin
Bitcoin utilizes the SHA-256 hashing algorithm, a National Security Agency (NSA)-developed encryption algorithm. SHA-256 prevents brute force attacks against the Bitcoin network, as decrypting it with current hardware can take decades. However, the emerging threat to SHA-256 is quantum computing, a method of computing that harnesses quantum physics and is much faster than traditional computing.
At a fundamental level, quantum computing utilizes quantum bits (qubits), which can exist in multiple states. This contradicts binary (traditional) computing, which uses binary bits (1s and 0s). In 1994, mathematician Peter Shor presented an algorithm for quantum computers to solve complex algorithms in seconds, rather than the decades it can take for conventional hardware. At the time, no hardware could effectively run it, but recent advances like Google Willow are nearing that capability.
Quantum computing, when paired with Shor’s algorithm, can disrupt Bitcoin cryptographic systems as we know them. Shor’s algorithm allows quantum computers to solve complex math super fast, potentially threatening Bitcoin’s safety.
Did you know? If quantum tech gets strong enough, Bitcoin’s current security could become obsolete, so developers are racing to create “quantum-proof” shields using new math that even Shor’s algorithm can’t break.
Quantum threat to Bitcoin: How real is the danger?
Bitcoin is vulnerable to quantum computing, but how serious is the risk?
When you create a crypto wallet, it generates two important things: a private key and a public key. The private key is a secret code, like a password, that you must keep safe. The public key is created from your private key, and your wallet address (like a bank account number) is made from the public key.
You share your wallet address with others so they can send you cryptocurrency, just like you share your email address for someone to contact you. However, you never share your private key. It’s like the password to your email — only you need it to access and spend the money in your wallet.
Your private key is like a master password that controls your crypto wallet. From this private key, your wallet can create many public keys, and each public key generates a wallet address.
For example, if you use a hardware wallet, it has one private key but can create unlimited public keys (wallet addresses). This means you can have different addresses for each cryptocurrency supported by the wallet or even multiple addresses for the same cryptocurrency, all managed by a single private key.
While generating a public key from a private key is straightforward, figuring out a private key from a public key is extremely hard — almost impossible — which keeps your wallet secure. Every time you send cryptocurrency, your private key creates a special code called a signature. This signature proves you own the funds and want to send them. The system that uses your private key, public key and signature to secure transactions is called the Elliptic Curve Digital Signature Algorithm (ECDSA).
It is believed that quantum computing could reverse the process and generate private keys out of public ones. It is feared that this could cause many Bitcoin holders (especially whales and Satoshi-era wallets) to lose their funds.
Bitcoin address types and quantum risks
When you send Bitcoin, you use a specific address type to direct the payment. Each address type has unique features, affecting security, privacy and vulnerability to quantum computing attacks like Shor’s algorithm.
P2PK address types
When you pay someone with Bitcoin, the transaction is typically considered a “pay-to-public-key” (P2PK). This was the most common payment method in 2009, according to a report from consulting firm Deloitte.
Much of the original Bitcoin released at the network’s launch is held in wallets with the P2PK address type, primarily due to the fact that they’ve sent transactions since Bitcoin’s 2009 launch. These addresses are long (up to 130 characters), making them less user-friendly.
Wallets with the P2PK address type are most susceptible to Shor’s algorithm, as it can brute force the private key from a P2PK wallet address.
P2PKH address…
cointelegraph.com