Commission Implementing Regulation (EU) 2016/799Show full title

5. Key Identifiers uniquely identify certificate holder or certification authorities. They are coded as follows: U.K.

5.1

Equipment (VU or Card):

Data	Equipment serial number	Date	Type	Manufacturer
Length	4 Bytes	2 Bytes	1 Byte	1 Byte
Value	Integer	mm yy BCD coding	Manufacturer specific	Manufacturer code

In the case of a VU, the manufacturer, when requesting certificates, may or may not know the identification of the equipment in which the keys will be inserted.

In the first case, the manufacturer will send the equipment identification with the public key to its Member State authority for certification. The certificate will then contain the equipment identification, and the manufacturer must ensure that keys and certificate are inserted in the intended equipment. The Key identifier has the form shown above.

In the later case, the manufacturer must uniquely identify each certificate request and send this identification with the public key to its Member State authority for certification. The certificate will contain the request identification. The manufacturer must feed back its Member State authority with the assignment of key to equipment (i.e. certificate request identification, equipment identification) after key installation in the equipment. The key identifier has the following form:

Data	Certificate request serial number	Date	Type	Manufacturer
Length	4 Bytes	2 Bytes	1 Byte	1 Byte
Value	Integer	mm yy BCD coding	‘FF’	Manufacturer code

5.2

Certification Authority:

Data	Authority Identification	Key serial number	Additional info	Identifier
Length	4 Bytes	1 Byte	2 Bytes	1 Byte
Value	1 Byte nation numerical code 3 Bytes nation alphanumerical code	Integer	additional coding (CA specific) ‘FF FF’ if not used	‘01’

The key serial number is used to distinguish the different keys of a Member State, in the case the key is changed.