@ Momo Tahmasbi
2025-02-01 18:51:52
## **Will Quantum Computers Kill Bitcoin? The Truth May Surprise You**
One of the biggest fears around Bitcoin is that quantum computers (QCs) will render it obsolete. But is this really a legitimate concern, or just another doomsday myth?
### The Real Threat: Not All Quantum Computers Are Equal
First, let’s get one thing straight: **quantum computers already exist**. The first notable ones appeared in the **1990s**, built by IBM and Stanford. So why hasn’t Bitcoin already been hacked? Because it’s not about whether quantum computers exist—it’s about how powerful they need to be.
### Are All Bitcoin Addresses at Risk?
No! If you’ve entered Bitcoin **after 2010** or **use a wallet backed up with 12 or 24 words (BIP-39, introduced in 2013)**, your funds are safe from quantum threats for a very long time—**centuries, at least**.
But why?
### Understanding How Bitcoin’s Security Works
Bitcoin security is based on **private keys**. (These are represented by the **12-24 words** you write down when setting up a wallet.) From this private key, a **public key** is created. In Bitcoin’s early days, people shared public keys directly to receive payments. But in 2010, Bitcoin introduced an extra layer of security: **hashed addresses**.
Now, instead of sharing your public key, your wallet generates a **Bitcoin address**, which is actually a **hash of your public key**. This adds an extra step for an attacker: before they can find your private key, they must first break the hash to reveal your public key.
### Two Steps to Breaking Bitcoin
To steal Bitcoin using quantum computing, an attacker must:
1. **Break the hash** (Bitcoin address → public key) using **Grover’s algorithm**.
2. **Break the elliptic curve cryptography** (public key → private key) using **Shor’s algorithm**.
### Where Do Quantum Computers Stand Today?
Let’s put things in perspective. **Google’s Willow processor**, which made headlines recently, has **105 physical qubits**. But breaking Bitcoin’s **elliptic curve cryptography** (step 2 above) requires about **2,330 logical qubits**, running for **minutes to hours**.
So how does 105 physical qubits compare to 2,330 logical qubits? It’s **not even in the same league**. To get 2,330 logical qubits, we'd likely need **millions of physical qubits**—a technology that is still decades away.
Now, even if we magically reached **2,330 logical qubits tomorrow**, that only breaks **public keys**. It still wouldn't be enough to break Bitcoin addresses (step 1), which would take **centuries** with current quantum algorithms.
### Who Should Be Worried?
- **People who used Bitcoin before 2010** and still have funds sitting in old public-key-based addresses (**P2PK** addresses). Their funds could be stolen **in minutes to hours** if a powerful enough quantum computer emerged.
- **People who reuse addresses**—this exposes the public key, making it vulnerable to a quantum attack, even when you are using more modern addresses. **(Many wallets, including Trust Wallet, SafePal, Exodus, and Atomic Wallet, still allow this bad practice!)**
### Who Can Sleep Soundly?
- **Anyone using modern Bitcoin addresses (P2PKH, SegWit, Taproot)**. Their addresses are **hashed**, meaning an attacker would need **centuries** to break the first layer of protection before even getting to the public key.
- **Anyone moving their coins periodically**—since modern Bitcoin wallets generate new addresses for each transaction, public keys remain hidden.
### The Concrete Wall Analogy
Think of your Bitcoin private key as being locked inside a massive vault. The first layer of protection is your Bitcoin address, which acts like a thick concrete wall. Cracking through this wall with current quantum algorithms would take centuries. Even if someone managed to break through, they would still face a second, much thinner barrier—your public key. This one would take only minutes to hours to breach. But by then, Bitcoin security upgrades would likely already be in place, leaving attackers empty-handed.
### But What If We Make a Huge Quantum Leap?
Yes, it’s possible that new quantum algorithms emerge, or that quantum hardware advances faster than expected. But Bitcoin’s development community isn’t sitting idle, waiting to get wrecked. There are already proposals for **quantum-resistant Bitcoin addresses**, and they can be implemented **before** quantum computers reach a dangerous level.
### The Bottom Line
🚀 **Quantum computers won’t kill Bitcoin anytime soon.**
📌 If you’re using a **modern Bitcoin wallet**, your funds are safe from quantum threats for the foreseeable future.
📌 If you reuse addresses, stop! It exposes your public key and makes you vulnerable much sooner.
📌 Bitcoin developers are already preparing for a quantum-resistant future.
So, no, quantum computers won’t be the end of Bitcoin. But they might be the end of bad security practices! 🔐