What is the difference between quantum computing and classical computing?

Classical computers use bits (0s and 1s) for calculations, while quantum computers use quantum bits or 'qubits' that can exist as both 0 and 1 simultaneously through superposition. This allows quantum computers to process vastly more possibilities at once. For cryptocurrency, quantum computing poses a theoretical threat: it could potentially break current encryption methods protecting Bitcoin and Ethereum wallets within decades. However, this risk is still distant—estimates suggest 10-15 years minimum. The crypto community is researching quantum-resistant algorithms now to prepare defenses. Classical computers remain standard for crypto mining and transactions today.