A mathematical calculation applied to the contents of a packet or file before and after it is transmitted. An encrypted message or file. Contrast with plaintext. Ensuring that information is not accessed by unauthorized persons. The art and science of keeping files and messages secure.
Decryption involves turning the ciphertext back into plaintext.
The mathematical function used for encryption and decryption is called a cryptographic algorithm or cipher. The art and science of breaking and decoding ciphertext, usually without prior knowledge of the secret key. Practiced by cryptanalysts. The branch of mathematics concerned with cryptography and cryptanalysis. A crytographic algorithm plus all possible plaintexts, ciphertext and keys.