Data security and Access control is a challenging research work in Cloud Computing. Cloud service users upload there private and confidential data over the cloud. Security must be provided to such outsourced data, so that user are not worried while uploading there confidential data. Recent technologies suffer from computational problem of keys and there exchange. This paper addresses the various problems and issues involved in using cloud services such as key generation, data security, authentication. This paper addresses this problem using access control technique that ensures only valid users will access there outsourced data. This paper proposes a Diffie-Hellman key exchange protocol between cloud service provider and the user for secretly sharing a symmetric key for secure data access that solves the problem of key distribution and management. Authentication will be done using Two Factor Authentication Technique with the help of key generated using Diffie-Hellman key exchange algorithm The proposed work is highly efficient and secure under existing security models.

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Cloud Computing Cryptography Access Control Security