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

3. KEYS AND CERTIFICATES

3.1. Keys generation and distribution

3.1.1 RSA Keys generation and distribution

CSM_006 RSA keys shall be generated through three functional hierarchical levels:

• European level,

• Member State level,

• Equipment level.

CSM_007 At European level, a single European key pair (EUR.SK and EUR.PK) shall be generated. The European private key shall be used to certify the Member States public keys. Records of all certified keys shall be kept. These tasks shall be handled by a European Certification Authority, under the authority and responsibility of the European Commission.

CSM_008 At Member State level, a Member State key pair (MS.SK and MS.PK) shall be generated. Member States public keys shall be certified by the European Certification Authority. The Member State private key shall be used to certify public keys to be inserted in equipment (vehicle unit or tachograph card). Records of all certified public keys shall be kept with the identification of the equipment to which it is intended. These tasks shall be handled by a Member State Certification Authority. A Member State may regularly change its key pair.

CSM_009 At equipment level, one single key pair (EQT.SK and EQT.PK) shall be generated and inserted in each equipment. Equipment public keys shall be certified by a Member State Certification Authority. These tasks may be handled by equipment manufacturers, equipment personalisers or Member State authorities. This key pair is used for authentication, digital signature and encipherement services

CSM_010 Private keys confidentiality shall be maintained during generation, transport (if any) and storage.

The following picture summarises the data flow of this process:

3.1.2 RSA Test keys

CSM_011 For the purpose of equipment testing (including interoperability tests) the European Certification Authority shall generate a different single European test key pair and at least two Member State test key pairs, the public keys of which shall be certified with the European private test key. Manufacturers shall insert, in equipment undergoing type approval tests, test keys certified by one of these Member State test keys.

3.1.3 Motion sensor keys

The confidentiality of the three Triple DES keys described below shall be appropriately maintained during generation, transport (if any) and storage.

In order to support tachograph components compliant with ISO 16844, the European Certification Authority and the Member State Certification Authorities shall, in addition, ensure the following:

CSM_036 The European Certification authority shall generate KmVU and KmWC, two independent and unique Triple DES keys, and generate Km as: Km = Km_VU XOR Km_WC. The European Certification Authority shall forward these keys, under appropriately secured procedures, to Member States Certification Authorities at their request.

CSM_037 Member States Certification Authorities shall:

• use Km to encrypt motion sensor data requested by motion sensor manufacturers (data to be encrypted with Km is defined in ISO 16844-3),

• forward Km_VU to vehicle unit manufacturers, under appropriately secured procedures, for insertion in vehicle units,

• ensure that Km_WC will be inserted in all workshop cards ( in elementary file) during card personalisation.

3.1.4 T-DES session keys generation and distribution

CSM_012 Vehicle units and tachograph cards shall, as a part of the mutual authentication process, generate and exchange necessary data to elaborate a common Triple DES session key. This exchange of data shall be protected for confidentiality through an RSA crypt-mechanism.

CSM_013 This key shall be used for all subsequent cryptographic operations using secure messaging. Its validity shall expire at the end of the session (withdrawal of the card or reset of the card) and/or after 240 use (one use of the key = one command using secure messaging sent to the card and associated response).

3.2. Keys

CSM_014 RSA keys shall have (whatever the level) the following lengths: modulus n1 024 bits, public exponent e 64 bits maximum, private exponent d1 024 bits.

CSM_015 Triple DES keys shall have the form (K_a, K_b, K_a) where K_a and K_b are independent 64 bits long keys. No parity error detecting bits shall be set.

3.3. Certificates

CSM_016 RSA Public key certificates shall be ‘non self-descriptive’‘Card Verifiable’ certificates (Ref.: ISO/IEC 7816-8)

3.3.1 Certificates content

CSM_017 RSA Public key certificates are built with the following data in the following order:

Data	Format	Bytes	Obs
CPI	INTEGER	1	Certificate Profile Identifier (‘01’ for this version)
CAR	OCTET STRING	8	Certification Authority Reference
CHA	OCTET STRING	7	Certificate Holder Authorisation
EOV	TimeReal	4	Certificate end of validity. Optional, ‘FF’ padded if not used.
CHR	OCTET STRING	8	Certificate Holder Reference
n	OCTET STRING	128	Public key (modulus)
e	OCTET STRING	8	Public Key (public exponent)
		164

Notes:

1. The ‘Certificate Profile Identifier’ (CPI) delineates the exact structure of an authentication certificate. It can be used as an equipment internal identifier of a relevant headerlist which describes the concatenation of Data Elements within the certificate.

The headerlist associated with this certificate content is as follows:

‘4D’

‘16’

‘5F 29’

‘01’

‘42’

‘08’

‘5F 4B’

‘07’

‘5F 24’

‘04’

‘5F 20’

‘08’

‘7F 49’

‘05’

‘81’

‘81 80’

‘82’

‘08’

Extended Headerlist Tag

Length of header list

CPI Tag

CPI Length

CAR Tag

CAR Length

CHA Tag

CHA Length

EOV Tag

EOV Length

CHR Tag

CHR Length

Public Key Tag (Constructed)

Length of subsequent DOs

modulus Tag

modulus length

public exponent Tag

public exponent length

2. The ‘Certification Authority Reference’ (CAR) has the purpose of identifying the certificate issuing CA, in such a way that the Data Element can be used at the same time as an Authority Key Identifier to reference the Public Key of the Certification Authority (for coding, see Key Identifier below).

3. The ‘Certificate Holder Authorisation’ (CHA) is used to identify the rights of the certificate holder. It consists of the Tachograph Application ID and of the type of equipment to which the certificate is intended (according to data element, ‘00’ for a Member State).

4. The ‘Certificate Holder Reference’ (CHR) has the purpose of identifying uniquely the certificate holder, in such a way that the Data Element can be used at the same time as a Subject Key Identifier to reference the Public Key of the certificate holder.

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

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.

6. Certificate verifiers shall implicitly know that the public key certified is an RSA key relevant to authentication, digital signature verification and encipherement for confidentiality services (the certificate contains no Object Identifier to specify it).

3.3.2 Certificates issued

CSM_018 The certificate issued is a digital signature with partial recovery of the certificate content in accordance with ISO/IEC 9796-2 (except for its annex A4), with the ‘Certification Authority Reference’ appended.

X.C = X.CA.SK[‘6A’ || C_r || Hash(Cc) || ‘BC’] || C_n || X.CAR

With certificate content = Cc =	Cr	||	Cn
	106 bytes		58 bytes

Notes:

1. This certificate is 194 bytes long.

2. CAR, being hidden by the signature, is also appended to the signature, such that the Public Key of the Certification Authority may be selected for the verification of the certificate.

3. The certificate verifier shall implicitly know the algorithm used by the Certification Authority to sign the certificate.

4. The headerlist associated with this issued certificate is as follows:

‘7F 21’	‘09’	‘5F 37’	‘81 80’	‘5F 38’	‘3A’	‘42’	‘08’
CV Certificate Tag (Constructed)	Length of subsequent DOs	Signature Tag	Signature Length	Remainder Tag	Remainder Length	CAR Tag	CAR Length

3.3.3 Certificate verification and unwrapping

Certificate verification and unwrapping consists in verifying the signature in accordance with ISO/IEC 9796-2, retrieving the certificate content and the public key contained: X.PK = X.CA.PK _o X.C, and verifying the validity of the certificate.

CSM_019 It involves the following steps:

• Verify signature and retrieve content:

  — from X.C retrieve Sign, Cn' and CAR':	X.C =	Sign	||	Cn'	||	CAR'
  		128 Bytes		58 Bytes		8 Bytes

  • from CAR' select appropriate Certification Authority Public Key (if not done before through other means)

  • open Sign with CA Public Key: Sr'= X.CA.PK [Sign],

  • check Sr' starts with ‘6A’ and ends with ‘BC’

  — compute Cr' and H' from: Sr' =	‘6A’	||	Cr'	||	H'	||	‘BC’
  			106 Bytes		20 Bytes

  • Recover certificate content C' = C_r' || C_n',

  • check Hash(C') = H'

• If the checks are OK the certificate is a genuine one, its content is C'.

• Verify validity. From C':

  • if applicable, check End of validity date,

• Retrieve and store public key, Key Identifier, Certificate Holder Authorisation and Certificate End of Validity from C':

  • X.PK = n || e

  • X.KID = CHR

  • X.CHA = CHA

  • X.EOV = EOV