Bitcoin cannot be counterfeited or duplicated due to its underlying technology known as blockchain. The blockchain is a decentralized and distributed ledger that records all transactions made with Bitcoin. Each transaction is verified by multiple participants in the network, known as miners, who compete to solve complex mathematical problems. Once a miner successfully solves the problem, the transaction is added to a block and linked to previous blocks, forming an immutable chain of transactions. This decentralized nature of the blockchain ensures transparency and security, making it extremely difficult for anyone to counterfeit or duplicate Bitcoin. Additionally, each Bitcoin has a unique digital signature that verifies its authenticity and prevents any form of tampering. Therefore, the design and implementation of Bitcoin's blockchain technology effectively eliminate the possibility of counterfeiting or duplicating this leading cryptocurrency.