Where does dictionary collide?

A dictionary attack guesses a password or key by trying candidates from a precompiled list of likely secrets (real words, common passwords, and known leaks) rather than searching the whole space exhaustively, because human-chosen secrets cluster in a tiny, predictable region. Morris and Thompson's Password Security: A Case History documented early systems where exactly this approach recovered a large share of user passwords, motivating salting and deliberately slow hashes. The referent is a guessing strategy that exploits the non-uniformity of chosen secrets, and it is unrelated to a key-value data structure or a learned set of signal atoms that share the name.[1]

Unit

Password/key guessing drawn from a curated list of likely candidates

Recovery means

Not applicable

Measured by

Gauged by the fraction of secrets cracked per guesses made against a candidate list

In signal processing and machine learning a dictionary is a collection of basis vectors, or atoms, from which signals are reconstructed as sparse combinations (using only a few atoms each), and dictionary learning is the problem of inferring such a set directly from data rather than fixing it in advance. Aharon, Elad, and Bruckstein's K-SVD gives an algorithm for learning an overcomplete dictionary for sparse representation. The referent is a learned overcomplete basis for compact signal coding, a different construct from a password wordlist or an associative array, sharing only the lookup metaphor.[2]

Unit

An overcomplete set of atoms used for sparse signal representation

Recovery means

Not applicable

Measured by

Assessed by sparsity of the representation and reconstruction error on held-out signals

In computer science a dictionary is an abstract data type that stores key–value pairs and supports looking up, inserting, and deleting a value by its key, commonly realised with hash tables or balanced search trees. It is one of the most heavily used structures in programming, underpinning symbol tables, caches, and associative arrays. Cormen, Leiserson, Rivest, and Stein's Introduction to Algorithms presents the dictionary operations and the structures that implement them efficiently. The referent is a keyed-access container, distinct from a password-guessing wordlist or a learned sparse basis despite the shared term.[3]

Unit

A key-indexed container supporting lookup, insert, and delete

Recovery means

Not applicable

Measured by

Characterised by the time complexity of search, insert, and delete operations