To access the distributed web applications in a computer network, mobile agents have long been proved to be a successful tool. The power of a mobile agent lies in migrating to the destination hosts directly for retrieving the information under consideration. Since many businesses run their sensitive data in distributed servers, it has been a mandatory demand that before the information is downloaded, the mobile agents need to be authenticated and authorized. To provide such authentication, digital signatures based on well known algorithms such as RSA, ECC have been proposed in the past. The main drawback of these works is that the they are not computationally efficient during the encryption and decryption of keys which are used to encrypt and decrypt the content. Thus, the major contribution of our work is to reduce the computational complexity for the authentication of mobile agents through a new hierarchical access management scheme. The computational costs are reduced during the key derivation and signature verification processes. The proposed work not only reduces the computational time, but provides flexibility to give fine grained access to the mobile agents to access only the authorized files. Extensive simulations prove that our approach significantly reduces the computational overhead than the recent works in the literature and hence this approach is best suited for implementation in the distributed web environments.