The public sector subject to the ENS around Bilbao has several layers, and it is worth not mixing them up. There is the Gobierno Vasco and its departments; there is the Diputación Foral de Bizkaia, with its own foral regime and its public companies, Lantik among them; there is the Ayuntamiento de Bilbao; there is the Universidad del País Vasco / Euskal Herriko Unibertsitatea; and there is Osakidetza, the Basque health service. All are public-sector entities for the purposes of Article 2.1 of RD 311/2022, which refers to Article 2 of Law 40/2015. What distinguishes them for a supplier is the procurement circuit and who acts as the technical counterpart, not the level of regulatory demand: the ENS is the same in Bilbao as anywhere else in Spain.
The obligation for the private company arises from Article 2.3, and its wording is direct: the royal decree also applies to the information systems of private-sector entities, «including the obligation to hold the security policy referred to in Article 12, when, in accordance with applicable regulations and under a contractual relationship, they provide services or supply solutions to public-sector entities for the exercise by these of their administrative competences and powers». That same article requires tender specifications to include the requirements needed to ensure conformity, «such as the presentation of the corresponding ENS Conformity Declarations or Certificates», and extends that caution to the contractor's supply chain. There is also a date that has already passed: the sole transitional provision gave pre-existing systems — expressly including those of private-sector contractors — twenty-four months to achieve full compliance, counted from entry into force on 5 May 2022.
In a project that is going to interconnect with already-certified foral platforms, the technical weight shifts to two places. The first is access control, the op.acc family of Annex II, because identification and authentication between systems of different organisations is where findings concentrate. The second is op.ext, external services, including op.ext.3, supply-chain protection. On top of that comes interconnection itself: the Centro Criptológico Nacional's CCN-STIC-811 guide recommends a DMZ in medium and high categories and places IDS/IPS as recommended at high category, and CCN-STIC-807 sets the admissible algorithms — TLS 1.2 as the minimum version, AES-256, SHA-256 or higher, with an HSM recommended at high category. Neither guide is the royal decree: they are the CCN's technical development, and are cited as such.