The phrase "clave única" refers to a digital identity system used in Chile called ClaveÚnica. It allows individuals to access state digital services and perform various official procedures online securely. It serves as a unique electronic identification for citizens to interact with public administrations and access a wide range of benefits and services.

In essence, [clave única](javascript:void(0)) means a "unique key" or "unique password," but in this context, it specifically denotes this official digital identity system in Chile.