Cloud computing is a multi-tenant computational paradigm that offers an efficient, elastic and scalable business model for organizations to adopt various information technology (IT) resources i.e. software, hardware, network, storage, bandwidth etc. There are various aspects of security problem in cloud computing field which include data security, privacy and users’ authenticity. The purpose of this research paper is to construct a framework for secure and more advanced authentication scheme for executing secure transactions in a cloud environment. For any cloud service which deals with personal and private information exchange, single tier authentication is not adequate. Authentication schemes that imply more than one tier for authentication are comparatively safer than single tier authentication scheme. This work proposes a scheme in which authentication process is carried out in two levels or two tiers. First tier uses simple username and password on a standard cloud user’s interface. Second tier is use of any personal device like mobile which have a unique id and in possession of the authenticated user only. The advantage of this scheme is that it enhances the strength of authentication as if cloud server has to authenticate the standard user password and id as well as the associated device’s id and password simultaneously with each other.