Cryptography is the science and practice of securing information by transforming it into a coded format, making it unreadable to unauthorized users. It uses mathematical techniques to encrypt (scramble) and decrypt (unscramble) data, ensuring that only intended recipients can access sensitive information. Cryptography is essential for protecting digital communications, financial transactions, and personal data from hackers and cybercriminals. It underpins many security technologies, such as secure messaging, online banking, and digital signatures, helping to maintain privacy, data integrity, and authentication in the digital world.