Encryption

Encryption transforms information into ciphertext so that it is intelligible only to someone with the appropriate key or method. It supports confidentiality but does not by itself ensure integrity or authenticity.

Plaintext: Information in its original, human-readable or otherwise usable form before encryption. Encryption begins with plaintext and transforms it into ciphertext.
Cryptography: The study and practice of techniques for securing information and communications against adversaries. Encryption is one family of techniques within this broader discipline.
Transport Layer Security: A cryptographic protocol that protects data exchanged between networked applications. It uses encryption to protect web and other network traffic in transit.
Hash function: A function that maps data to a fixed-length digest, designed to be difficult to reverse. Unlike encryption, hashing is not designed to recover the original data with a key.
Ciphertext: Information transformed by encryption into a form not readily understood without the required key or method. It is the output that encryption is designed to conceal.
Cryptanalysis: The analysis of cryptographic systems to recover hidden information or find weaknesses without authorized access. It tests whether ciphertext can be understood without the intended key.
End-to-end encryption: A communication design in which only the communicating endpoints hold the keys needed to read messages. It prevents service providers from decrypting message contents in transit.
Digital signature: A cryptographic value that lets others verify a message's origin and detect changes using public-key methods. Signatures establish authenticity and integrity, while encryption primarily provides confidentiality.
Cryptographic key: A value used by a cryptographic algorithm to encrypt, decrypt, or otherwise transform data. The key determines who can reverse a given encryption operation.
Entropy (information theory): A measure of uncertainty in a random variable, commonly used to quantify unpredictability. Unpredictable keys are harder for attackers to guess.

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