Keyed

Keyed is the past participle of key and an adjective used in several domains to indicate that something is associated with or controlled by a key.

In locksmithing and security, a keyed lock requires a physical key to operate. Locks can be keyed-alike, meaning multiple locks share the same key, or keyed-different, meaning each lock uses a distinct key. A master key system employs a hierarchy of keys that can open multiple locks. Key control and key management involve issuing, tracking, and revoking keys.

In cryptography, a keyed function uses a secret key to influence the computation. This includes keyed hash functions and encryption algorithms. Keyed hashes, such as HMAC, provide integrity and authenticity, while key management is critical to maintaining secrecy and access control of keys.

In data structures and software, a keyed data structure uses keys as identifiers to access values, as in dictionaries or maps where each entry is looked up by its key.

In music, keyed instruments are those that use keys, such as keyed flutes and keyboards. The presence of keys enables chromatic pitches and facilitates certain scales and tunings.

In common usage, to key something can also mean to scratch its surface with a sharp object, as in vandalism—for example, to key a car or door.

Etymology traces keyed to key, with usage spanning security, computing, music, and everyday language.