Disclosed is a cryptographic key distribution method and apparatus for installing a cryptographic key in an ECU. The method comprises: establishing a first communication link between the ECU and a key source; sending, via the first link, a first cryptographic key from the key source to the ECU; establishing a second communication link between the key source and a key manager; sending, via the second link, the first key from the key source to the key manager; encrypting, by the key manager, using the first key, a second cryptographic key; sending, by the key manager, to the ECU, the encrypted second key; and decrypting, by the ECU, using the first key, the encrypted second key, thereby providing the ECU with the second key.