ENS (Esquema Nacional de Seguridad) accreditation scheme has been developed by ENAC (Entidad Nacional de Acreditación) closely with the Ministry of Finance and Public Administration and the CCN (National Cryptologic Centre). This comprises of basic principles and minimum requirements necessary for the adequate protection of information. Requirements are associated to access, integrity, availability, authenticity, confidentiality, traceability and preservation of data.
For additional information around ENS please visit here.