Threshold Cryptography Based Data Security in Cloud Computing

Cloud computing is very popular in organizations and institutions because it provides storage and computing services at very low cost. However, it also introduces new challenges for ensuring the confidentiality, integrity and access control of the data. Some approaches are given to ensure these security requirements but they are lacked in some ways such as violation of data confidentiality due to collusion attack and heavy computation (due to large no keys). To address these issues we propose a scheme that uses threshold cryptography in which data owner divides users in groups and gives single key to each user group for decryption of data and, each user in the group shares parts of the key. In this paper, we use capability list to control the access. This scheme not only provides the strong data confidentiality but also reduces the number of keys.