How does blockchain ensure the security of cryptocurrency transactions?

Blockchain ensures the security of cryptocurrency transactions through cryptographic methods and decentralized consensus. Each block contains a unique cryptographic hash of the preceding block, forming an unalterable chain. Consensus mechanisms like Proof of Work or Proof of Stake validate transactions, making it challenging for malicious actors to manipulate the blockchain. This distributed and transparent approach to recording transactions enhances by eliminating the need for centralized authority and minimizing the risk of fraud or tampering.