Privacy preserving ciphertext policy attribute based encryption scheme with efficient and constant ciphertextsize

Ciphertext-Policy Attribute-Based Encryption (CP-ABE) is a well-known access control technique enforces effective data access policies, where each access policy consists of many attributes. At present, the application of CP-ABE among cloud computing applications has obtained significant attention due to its flexibility and dynamic decision-making capabilities. In most of the existing CP-ABE schemes the size of the ciphertext increases linearly with increase in a number of attributes in access policy which incurs very large ciphertext size leading to computational overheads and several security infringements. In this paper, we propose a privacy-preserving CP-ABE scheme that significantly reduces the ciphertext size to be constant with any number of the user given attributes in a meaningful manner. The proposed system solves the problem of increasing ciphertext size through the construction of dispensability matrix which eliminates redundant attributes from the system. The experiment shows that our proposed system better solve the issue of data privacy and computational overheads.