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

10.2.2 VU Certificate Chain Verification by Card U.K.

CSM_161 [F1 Tachograph cards shall use the protocol depicted in Figure 5 for verifying a VU's certificate chain. For every certificate presented by the VU, the card shall verify that the Certificate Holder Authorisation (CHA) field is correct: U.K.

• The CHA of the VU.Link certificate shall indicate the ERCA.

• The CHA of the VU.CA certificate shall indicate an MSCA.

• The CHA field of the VU certificate shall indicate a VU certificate for mutual authentication (see Appendix 1, data type EquipmentType).]

Textual Amendments

F1 Substituted by Commission Implementing Regulation (EU) 2018/502 of 28 February 2018 amending Implementing Regulation (EU) 2016/799 laying down the requirements for the construction, testing, installation, operation and repair of tachographs and their components (Text with EEA relevance).

Figure 5

Protocol for VU Certificate Chain Verification by Card

Notes to Figure 5: U.K.

— The VU certificates and public keys mentioned in the figure are those for mutual authentication. Section 9.1.4 denotes these as VU_MA. U.K.

— The VU.CA certificates and public keys mentioned in the figure are those for signing VU and external GNSS facility certificates. Section 9.1.3 denotes these as MSCA_VU-EGF. U.K.

— The VU.CA.EUR certificate mentioned in the figure is the European root certificate that is indicated in the CAR of the VU.CA certificate. U.K.

— The VU.Link certificate mentioned in the figure is the VU's link certificate, if present. As specified in section 9.1.2, this is a link certificate for a new European root key pair created by the ERCA and signed by the previous European private key. U.K.

— The VU.Link.EUR certificate is the European root certificate that is indicated in the CAR of the VU.Link certificate. U.K.

CSM_162 As depicted in Figure 5, verification of the certificate chain of the vehicle unit shall begin with the vehicle unit attempting to set its own public key for use in the tachograph card. If this succeeds, it means that the card successfully verified the VU's certificate chain in the past, and has stored the VU certificate for future reference. In this case, the VU certificate is set for use and the process continues with VU Authentication. If the card does not know the VU certificate, the VU shall successively present the VU.CA certificate to be used for verifying its VU certificate, the VU.CA.EUR certificate to be used for verifying the VU.CA certificate, and possibly the link certificate, in order to find a certificate known or verifiable by the card. If such a certificate is found, the card shall use that certificate to verify the underlying VU certificates presented to it. If successful, the VU shall finally set its public key for use in the tachograph card. If not successful, the VU shall ignore the card. U.K.

Note: There are three ways in which the card may know the VU.CA.EUR certificate: U.K.

— the VU.CA.EUR certificate is the same certificate as the card's own EUR certificate; U.K.

— the VU.CA.EUR certificate precedes the card's own EUR certificate and the card contained this certificate already at issuance (see CSM_91); U.K.

— the VU.CA.EUR certificate succeeds the card's own EUR certificate and the card received a link certificate in the past from another vehicle unit, verified it and stored it for future reference. U.K.

CSM_163 The VU shall use the MSE: Set AT command to set its public key for use in the tachograph card. As specified in Appendix 2, this command contains an indication of the cryptographic mechanism that will be used with the key that is set. This mechanism shall be ‘VU Authentication using the ECDSA algorithm, in combination with the hashing algorithm linked to the key size of the VU's VU_MA key pair, as specified in CSM_50’. U.K.

CSM_164 The MSE: Set AT command also contains an indication of the ephemeral key pair which the VU will use during session key agreement (see section 10.4). Therefore, before sending the MSE: Set AT command, the VU shall generate an ephemeral ECC key pair. For generating the ephemeral key pair, the VU shall use the standardized domain parameters indicated in the card certificate. The ephemeral key pair is denoted as (VU.SK_eph, VU.PK_eph, Card.DP). The VU shall take the x-coordinate of the ECDH ephemeral public point as the key identification; this is called the compressed representation of the public key and denoted as Comp(VU.PK_eph). U.K.

[F1 CSM_165 If the MSE: Set AT command is successful, the card shall set the indicated VU.PK for subsequent use during Vehicle Authentication, and shall temporarily store Comp(VU.PKeph). In case two or more successful MSE: Set AT commands are sent before session key agreement is performed, the card shall store only the last Comp(VU.PKeph) received. The card shall reset Comp(VU.PKeph) after a successful GENERAL AUTHENTICATE command.] U.K.

CSM_166 The card shall verify the temporal validity of any certificate presented by the VU or referenced by the VU while stored in the card's memory, and shall reject expired certificates. U.K.

CSM_167 For verifying the temporal validity of a certificate presented by the VU, each tachograph card shall internally store some data representing the current time. This data shall not be directly updatable by a VU. At issuance, the current time of a card shall be set equal to the Effective Date of the card's Card_MA certificate. A card shall update its current time if the Effective Date of an authentic ‘valid source of time’ certificate presented by a VU is more recent than the card's current time. In that case, the card shall set its current time to the Effective Date of that certificate. The card shall accept only the following certificates as a valid source of time: U.K.

• Second-generation ERCA link certificates

• Second-generation MSCA certificates

• Second-generation VU certificates issued by the same country as the card's own card certificate(s).

Note: the last requirement implies that a card shall be able to recognize the CAR of the VU certificate, i.e. the MSCA_VU-EGF certificate. This will not be the same as the CAR of its own certificate, which is the MSCA_Card certificate. U.K.

CSM_168 As indicated in Figure 5, once the card has verified the authenticity and validity of a previously unknown certificate, it may store this certificate for future reference, such that it does not need to verify that certificate's authenticity again if it is presented to the card again. Instead xof storing the entire certificate, a card may choose to store only the contents of the Certificate Body, as specified in section 9.3.2. U.K.