Definition
Encryption is the process of converting readable data, known as plaintext, into an unreadable format called ciphertext. This transformation uses an algorithm and a secret key, ensuring that only authorized parties with the correct key can decrypt the data back into its original form. In practice, encryption is applied to protect sensitive information during transmission over networks or when stored on devices. It is crucial for maintaining data confidentiality and integrity, preventing unauthorized access and breaches. For instance, secure websites use encryption to protect credit card numbers during online transactions. Unlike pseudonymization, which replaces direct identifiers with artificial ones, encryption renders the data itself unintelligible without the key. This fundamental security concept is extensively covered in certifications like CompTIA Security+, CySA+, and CISSP.