Encryption is the conversion of data into a secret code. The purpose of encryption is to prevent unauthorised parties from accessing the data (i.e. protecting the confidentiality of the data).

Encryption works by taking the unencrypted data (known as plaintext), applying the process of an encryption algorithm on it (which is always done with a key, and sometimes also takes a password too), resulting in the encrypted text (known as ciphertext). Decryption of the ciphertext requires a key, with different types of key depending on the type of encryption that was used.

There are two main kinds of encryption: public-key encryption (also known as assymetric encryption) and symmetric encryption. Encryption is widely used in data security, and is frequently used in instances even when it may not obviously be the case. For example, websites and phone applications frequently use encrypted communications in order to prevent third parties accessing information when it is being passed between the sender and receiver (a man-in-the-middle attack).


Last updated: 2 September 2017