CSM_100A number of symmetric keys is needed for pairing vehicle units and motion sensors, for mutual authentication between vehicle units and motion sensors and for encrypting communication between vehicle units and motion sensors, as shown in Table 3. All of these keys shall be AES keys, with a key length equal to the length of the motion sensor master key, which shall be linked to the length of the (foreseen) European root key pair as described in CSM_50.U.K.
| Table 3 | ||||
| Keys for securing vehicle unit — motion sensor communication | ||||
| a Storage of KM and KID is optional, as these keys can be derived from KM-VU, KM-WC and CV. | ||||
| Key | Symbol | Generated by | Generation method | Stored by |
|---|---|---|---|---|
| Motion Sensor Master Key — VU part | KM-VU | ERCA | Random | ERCA, MSCAs involved in issuing VUs certificates, VU manufacturers, vehicle units |
| Motion Sensor Master Key — Workshop part | KM-WC | ERCA | Random | ERCA, MSCAs, card manufacturers, workshop cards |
| Motion Sensor Master Key | KM | Not independently generated | Calculated as KM = KM-VU XOR KM-WC | ERCA, MSCAs involved in issuing motion sensors keys (optionally)a |
| Identification Key | KID | Not independently generated | Calculated as KID = KM XOR CV, where CV is specified in CSM_106 | ERCA, MSCAs involved in issuing motion sensors keys (optionally)a |
| Pairing Key | KP | Motion sensor manufacturer | Random | One motion sensor |
| Session Key | KS | VU (during pairing of VU and motion sensor) | Random | One VU and one motion sensor |