encrypting

Encrypting is the process of transforming readable data, or plaintext, into an unreadable form called ciphertext to prevent unauthorized access. The transformation uses an algorithm, known as a cipher, and a key. Decryption reverses the process, restoring the original plaintext when the correct key is available. Encryption aims to protect confidentiality, ensuring that only authorized parties can read the information, whether data is stored (at rest) or transmitted (in transit).

Encryption can be broadly categorized as symmetric encryption, where the same key is used for encryption and decryption, and asymmetric (public-key) encryption, which uses a pair of mathematically related keys. Common symmetric algorithms include AES and ChaCha20, often used with an authenticated mode such as GCM to provide both confidentiality and integrity. Common asymmetric algorithms include RSA and ECC-based schemes, which enable key exchange, digital signatures, and authentication without sharing a private key. Modern protocols increasingly rely on authenticated encryption and careful key management to prevent tampering and eavesdropping.

Applications include securing data at rest on devices and servers, protecting communications over networks (for example, TLS/HTTPS), and enabling email and file encryption. Important properties of encryption systems are confidentiality, integrity, and, where applicable, authenticity and non-repudiation via digital signatures. Limitations include the need for secure key management, potential weaknesses in implementations, and the threat of quantum computers to certain algorithms. The field has evolved from classical ciphers to modern public-key cryptography beginning in the 1970s, with widely deployed standards and ongoing research to address emerging threats and performance requirements.