Council Decision 2013/488/EU of 23 September 2013 on the security rules for protecting EU classified information

Article 2 - Definition of EUCI, security classifications and markings
‘1. ‘EU classified information’ (EUCI) means any information or material designated by a EU security classification, the unauthorised disclosure of which could cause varying degrees of prejudice to the interests of the European Union or of one or more of the Member States. [...]‘
Article 7 - Personnel security
‘1. Personnel security is the application of measures to ensure that access to EUCI is granted only to individuals who have:
— a need-to-know,
— been security cleared to the relevant level, where appropriate, and
— been briefed on their responsibilities. [...]‘