An encryption algorithm secures data by transforming plaintext into ciphertext, making it unreadable without the corresponding decryption key. This typically involves a series of mathematical transformations and key generation processes that protect sensitive information from unauthorized access. When a user wishes to access the original data, they must provide the correct key, allowing the encryption algorithm to reverse the process. Strong encryption algorithms are essential for safeguarding personal, financial, and corporate data against breaches and cyber threats.