An identity-based encryption technique using subtree for fuzzy user data sharing under cloud computing environment

The advancement of the cloud storage technology opens up a wide range of possibilities for adaptable data sharing. When sharing data to an extensive number of users with fuzzy identities, the data proprietor must use an appropriate identity-based encryption technique that satisfies both efficiency and security prerequisites. Identity-based encryption is a promising possibility to ensure fuzzy user data sharing while meeting the security essentials; however, it may encounter efficiency trouble in multi-receiver settings. Recently, identity-based encryption has received much attention, and most of the research has aimed to apply the technique in real-world systems. A major concern about using identity-based encryption is the safety of the private keys, as disclosure of secret keys requires the reissuing of encryptions already doled out. The capability to minimize the risks associated with key disclosure is particularly important due to the increased use of mobile and unprotected devices. In this article, we shall propose a forward-secure identity-based encryption technique based on subtree for fuzzy user data sharing under cloud computing environment, and we shall demonstrate that the technique is semantically secure against a chosen subtree and chosen ciphertext attack (IND-CST–CCA). In addition, we will show the superiority of our new technique over the currently existing methods in terms of security and the length of public key. Then, we will also discuss the potential of our new technique to be deployed in pay TV systems and grid security.