19\. März 2025
### 🔐 1. SHA-256 is Quantum-Resistant
Bitcoin’s **proof-of-work** mechanism relies on SHA-256, a hashing algorithm. Even with a powerful quantum computer, **SHA-256 remains secure** because:
- Quantum computers excel at **factoring large numbers** (Shor’s Algorithm).
- However, **SHA-256 is a one-way function**, meaning there's no known quantum algorithm that can efficiently reverse it.
- **Grover’s Algorithm** (which theoretically speeds up brute force attacks) would still require **2¹²⁸ operations** to break SHA-256 – far beyond practical reach.
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### 🔑 2. Public Key Vulnerability – But Only If You Reuse Addresses
Bitcoin uses **Elliptic Curve Digital Signature Algorithm (ECDSA)** to generate keys.
- A quantum computer could use **Shor’s Algorithm** to break **SECP256K1**, the curve Bitcoin uses.
- If you never reuse addresses, it is an additional security element
- 🔑 1. Bitcoin Addresses Are NOT Public Keys
Many people assume a **Bitcoin address** is the public key—**this is wrong**.
- When you **receive Bitcoin**, it is sent to a **hashed public key** (the Bitcoin address).
- The **actual public key is never exposed** because it is the Bitcoin Adress who addresses the Public Key which never reveals the creation of a public key by a spend
- Bitcoin uses **Pay-to-Public-Key-Hash (P2PKH)** or newer methods like **Pay-to-Witness-Public-Key-Hash (P2WPKH)**, which add extra layers of security.
### 🕵️♂️ 2.1 The Public Key Never Appears
- When you **send Bitcoin**, your wallet creates a **digital signature**.
- This signature uses the **private key** to **prove** ownership.
- The **Bitcoin address is revealed and creates the Public Key**
- The public key **remains hidden inside the Bitcoin script and Merkle tree**.
This means: ✔ **The public key is never exposed.** ✔ **Quantum attackers have nothing to target, attacking a Bitcoin Address is a zero value game.**
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### 🔄 3. Bitcoin Can Upgrade
Even if quantum computers **eventually** become a real threat:
- Bitcoin developers can **upgrade to quantum-safe cryptography** (e.g., lattice-based cryptography or post-quantum signatures like Dilithium).
- Bitcoin’s decentralized nature ensures a network-wide **soft fork or hard fork** could transition to quantum-resistant keys.
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### ⏳ 4. The 10-Minute Block Rule as a Security Feature
- Bitcoin’s network operates on a **10-minute block interval**, meaning:Even if an attacker had immense computational power (like a quantum computer), they could only attempt an attack **every 10 minutes**.Unlike traditional encryption, where a hacker could continuously brute-force keys, Bitcoin’s system **resets the challenge with every new block**.This **limits the window of opportunity** for quantum attacks.
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### 🎯 5. Quantum Attack Needs to Solve a Block in Real-Time
- A quantum attacker **must solve the cryptographic puzzle (Proof of Work) in under 10 minutes**.
- The problem? **Any slight error changes the hash completely**, meaning:**If the quantum computer makes a mistake (even 0.0001% probability), the entire attack fails**.**Quantum decoherence** (loss of qubit stability) makes error correction a massive challenge.The computational cost of **recovering from an incorrect hash** is still incredibly high.
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### ⚡ 6. Network Resilience – Even if a Block Is Hacked
- Even if a quantum computer **somehow** solved a block instantly:The network would **quickly recognize and reject invalid transactions**.Other miners would **continue mining** under normal cryptographic rules.**51% Attack?** The attacker would need to consistently beat the **entire Bitcoin network**, which is **not sustainable**.
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### 🔄 7. The Logarithmic Difficulty Adjustment Neutralizes Threats
- Bitcoin adjusts mining difficulty every **2016 blocks (\~2 weeks)**.
- If quantum miners appeared and suddenly started solving blocks too quickly, **the difficulty would adjust upward**, making attacks significantly harder.
- This **self-correcting mechanism** ensures that even quantum computers wouldn't easily overpower the network.
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### 🔥 Final Verdict: Quantum Computers Are Too Slow for Bitcoin
✔ **The 10-minute rule limits attack frequency** – quantum computers can’t keep up.
✔ **Any slight miscalculation ruins the attack**, resetting all progress.
✔ **Bitcoin’s difficulty adjustment would react, neutralizing quantum advantages**.
**Even if quantum computers reach their theoretical potential, Bitcoin’s game theory and design make it incredibly resistant.** 🚀
