The Core Strength Absolutely — Bitcoin’s network is the most secure decentralized system ever built. It relies on proof-of-work (PoW), where miners expend massive energy (850+ EH/s hashrate in December 2025) to validate transactions and add blocks.

pchojecki.medium.com A 51% attack — controlling over half the hashrate to rewrite history — costs billions and only affects recent transactions (e.g., double-spends under 6 confirmations). In practice, no attacker has come close; the economics deter it. Privacy shines too: Pseudonymity via fresh addresses keeps most users untraceable, though chain analysis tools expose sloppy habits. Upgrades like Taproot (2021) enhance script privacy without compromising speed. Hasn’t Bitcoin Been Hacked in the Past? No — the Bitcoin blockchain itself has never been compromised. Every satoshi since Genesis Block #0 remains intact, thanks to immutable consensus rules enforced by 20,000+ full nodes worldwide.

forbes.com Hacks target users or platforms, not the protocol:

• Mt. Gox (2014): $450M stolen via poor exchange security (weak multisig).
• Binance (2019): $40M hot wallet breach.
• 2024–2025 Incidents: Upbit lost $50M to insider theft; total exchange hacks hit $1.7B in 2024 alone, per Chainalysis. frontiersin.org

Lesson? Self-custody your keys. Use hardware wallets like Jade, Keystone 3 Pro or ColdCard, enable multisig, and avoid leaving funds on exchanges. In 2025, insured custodians (e.g., Fidelity Digital) add layers, but “not your keys, not your coins” still rules. Could Users Collude Against Bitcoin? Collusion is possible but impractical and self-defeating. A 51% attack requires coordinated control of mining power — think nation-states or cartels pooling ASICs. Even then:

• Short-Term Damage: Reverse recent txs or censor blocks, but the network recovers via honest nodes rejecting invalid chains.
• Long-Term Cost: Attackers devalue BTC (their own asset), crashing prices and hashrate. Post-2024 halving, a sustained attack exceeds $10B/day in opportunity costs.
• Real-World Check: In 2025, hashrate is 65% North American, diversified across public firms like Marathon and Riot — no single entity dominates. pchojecki.medium.com

Users (holders/miners) align incentives: Everyone benefits from security. Collusion would trigger mass exits to alternatives like Ethereum, eroding the plotters’ wealth. Is Bitcoin Vulnerable to Quantum Computing? Yes, but not imminently — and fixes are in motion. Quantum computers threaten ECDSA signatures via Shor’s algorithm, potentially deriving private keys from public ones. Vulnerable addresses? ~$718B in BTC (P2PK or reused keys) where pubkeys are exposed.

chainalysis.com

• Timeline: Experts split — some say Q-Day (crypto-breaking quantum) hits post-2030; others warn of “harvest now, decrypt later” attacks already underway (saving blockchain data for future cracks). thequantuminsider.com +1 Breaking secp256k1 needs ~2,330 logical qubits (millions physical) — far beyond 2025’s 200-qubit prototypes like Google’s Willow. pchojecki.medium.com +1
• Mitigations: Migrate to post-quantum crypto (e.g., NIST’s Dilithium). 2025 proposals like QRAMP enforce address swaps via soft forks — no hard fork needed. pchojecki.medium.com +1 Taproot addresses (pay-to-script-hash) buy time by hiding pubkeys until spent. Community debate rages (e.g., Lopp’s “Against Quantum Recovery”), but awareness is high — BlackRock even flagged it in ETF filings. cointelegraph.com

Bottom line: Quantum risks are real but distant (2030+ for most). Act now: Use fresh Taproot addresses, avoid key reuse, and watch BIPs for upgrades. Secure Your Stack Todaym Bitcoin’s security isn’t perfect — it’s engineered for adversarial conditions, not utopias. In 2025, with $2T+ market cap, it withstands daily assaults from hackers, regulators, and FUD. Run a node, self-custody wisely, and stay informed. True sovereignty means owning the risks — and the rewards. Ready to HODL unbreakable? Start with a multisig setup and quantum-aware habits.

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Bitcoin Security: Don’t let your lack of knowledge hold you back from investing in Bitcoin.