doublelock

Doublelock is a term used to describe devices or procedures that require two independent locks, checks, or approvals to access a protected space or resource. It is not a single standardized device, but a concept used across domains to add redundancy and require dual-control.

In physical security, a double-lock mechanism can pair a traditional mechanical lock with a supplementary locking bolt, or use two separate locks operated by different keys or combinations. Some safes and vault doors employ a double-locking bolt that must be retracted by both actuators, often with a time delay or sequential release to enforce dual-control.

In banking and high-security facilities, double-locking is commonly implemented as two-key or two-person controls. This means two authorized individuals must participate to unlock or authorize a transaction, reducing the risk of insider theft and enabling audits. The system may require simultaneous action or staged steps with independent authorization.

In computing and information security, “double lock” is an informal term for dual-authorization workflows or dual-key cryptographic schemes that require two separate credentials or keys to perform a sensitive operation. This can be part of access control, key management, or emergency shutdown procedures, complementing other safeguards like authentication and logging.

Origin and usage: While implementations vary, the common thread is redundancy and dual-control. The term appears in security engineering, vault design, and enterprise IT, often described as dual-control, two-person rule, or parallel authorization, depending on the context.