- See also changes related to Cryptanalysis, or pages that link to Cryptanalysis or to this page or whose text .
- Cryptography : A field at the intersection of mathematics and computer science that is concerned with the security of information, typically the confidentiality, integrity and authenticity of some message.
- Information theory : Theory of the probability of transmission of messages with specified accuracy when the bits of information constituting the messages are subject, with certain probabilities, to transmission failure, distortion, and accidental additions.
- Frequency analysis : Add brief definition or description
- Index of coincidence : Add brief definition or description
- Kasiski attack : Add brief definition or description
- Kappa test : Add brief definition or description
- Passive attack : An attack on a communications system in which the attacker reads messages he is not supposed to but does not alter them.
- Active attack : An attack on a communications system in which the attacker creates, alters, replaces, re-routes or blocks messages; this contrasts with a passive attack in which he only reads them.
- : Attacking a cipher using linear approximations to its components' behaviour; the objective is to build up an overall approximation that breaks the cipher.
- : Attacking a cipher by studying the way that small changes in input, such as complementing a single bit, affect the output.
- Brute force attack : An attempt to break a cipher by trying all possible keys; long enough keys make this impractical.
- Code book attack : Attacking a block cipher by creating a code book, collecting plaintext/ciphertext pairs.
- Algebraic attack : Attacking a cipher by writing equations that describe its operation, then solving for the key.
- Birthday attack : An attack on a cryptographic system that works by finding two identical outputs from the system.
- Meet-in-the-middle attack : An attack on a block cipher in which the attacker can calculate possible values of the same intermediate variable (the middle) in two independent ways, starting either from the input of the cipher (plaintext) or from the output ( ciphertext); he calculates some possible values each way and compares the results.
- Zimmerman telegram : Add brief definition or description
- ULTRA : ULTRA was the main code word, in the Second World War, for British signals intelligence directed at Nazi Germany.
- MAGIC : Add brief definition or description
- Man-in-the-middle attack : An attack on a communications system in which the attacker deceives the communicating parties so they both talk to him while believing they are talking to each other.
- Traffic analysis : Traffic analysis is a branch of signals intelligence, inferring useful information from messages without actually reading them.