A system and method for identity (ID)-based key management are provided. The ID-based key management system includes an authentication server configured to authenticate a terminal through key exchange based on an ID and a password of a user of the terminal, set up a secure channel with the terminal, and provide a private key based on the ID of the user to the terminal through the secure channel, and a private-key generator configured to generate the private key corresponding to the ID of the terminal user according to a request of the authentication server.