Definition
Cryptography is the practice and study of techniques for secure communication in the presence of adversaries. It involves transforming information, called plaintext, into an unreadable format, called ciphertext, using algorithms and keys. This transformation ensures that only authorized parties can decipher and understand the original message. Cryptography is fundamental to protecting sensitive data, verifying identities, and maintaining the integrity of digital transactions. For instance, secure websites use cryptography to encrypt your credit card details during online purchases. It is distinct from steganography, which hides the very existence of a message. Understanding cryptography is essential for security professionals and appears on exams like CompTIA Security+, CySA+, and CISSP.