Encryption: Frequently Asked Questions, Chris Jaikaran, Analyst in Cybersecurity Policy. September 28, 2016.

“Encryption is a process to secure information from unwanted access or use. Encryption uses the art of cryptography to change information which can be read (plaintext) and make it so that it cannot be read (ciphertext). Decryption uses the same art of cryptography to change that ciphertext back to plaintext. Encryption takes five elements to work: plaintexts, keys, encryption methods, decryption methods, and ciphertexts. Data that are in a state of being stored or in a state of being sent are eligible for encryption. However, data that are in a state of being processed—that is being generated, altered, or otherwise used—are unable to be encrypted and remain in plaintext and vulnerable to unauthorized access.”