A network function virtualization system, comprises a request receiving unit that receives a request to a certificate of at least one of data exchanging parties; a private key generator that generates a first private key information using a second private key information stored in a hardware-based isolated secure execution environment, in response to the request; a public key extractor that extracts a public key information of the first private key information; a public key information storage unit that stores the public key information; and a verifying unit that is accessible from the request receiving unit and verifies the certificate using the public key information corresponding to the certificate.