According to an aspect, a method performed by a first controller for providing security for multiple second controllers in an in-vehicle network, includes transmitting an inherent information request to a suspicious controller of the second controllers for inherent information of the suspicious controller, the inherent information request including a certificate assigned to the first controller, and receiving an encrypted inherent information of the suspicious controller from the suspicious controller, the encrypted inherent information having been encrypted with a public key associated with the certificate, and using a private key associated with the certificate for obtaining decrypted inherent information from the encrypted inherent information, and comparing the decrypted inherent information with pre-stored inherent information, and determining the suspicious controller to be an anomalous controller when the decrypted inherent information is different from the pre-stored inherent information.