Double-spending is when someone tries to spend the same cryptocurrency more than once. It’s a serious risk in digital money systems because, unlike physical cash, digital files can be copied. If not prevented, it could damage trust, cause inflation, and threaten the entire system.
Blockchain technology solves this by using decentralized consensus—where many computers agree on a single version of transaction history. Bitcoin, for example, uses proof-of-work to make tampering with the ledger nearly impossible. Attacks like the 51% attack, where someone controls most of the network, can still happen but are extremely difficult and expensive on major blockchains.
Strong security, clear rules, and user awareness (like waiting for confirmations before accepting payments) help prevent double-spending and keep digital currencies reliable.
