Due to the explosive growth of the Internet and the pervasion of multimedia, protection of IP rights of digital content in transactions induces people's concerns. Current security requirements and copyright protection mechanisms need to work in real-time. For media service systems in the Internet, user's authentication is most essential in association with the access control of the media system. Many one-time password-based authentication schemes have been proposed. However, none is secure enough. The purpose of a one-time password (OTP) is to make it more difficult to gain unauthorized access to restricted resources. These schemes are specially fit for media services in the Internet since they will frustrate the attacker's attempt. Lin, Shen and Hwang proposed a strong-password authentication scheme using smart cards. Later, Ku proposed a hash-based strong-password authentication scheme without using smart card to enhance the security. However, it still has the intrinsic weakness and suffers some attacks. In this paper, we enhance the Ku's scheme and propose a novel one-time-Password Authentication scheme in media services.