Investigating the Approaches for improving the Ciphertext Policy Attribute Based Encryption schemes

Ciphertext policy attribute based encryption (CP-ABE) is a technique in which a user with a secret key (containing attributes) is able to decrypt a message only if the attributes in the policy match those defined in the secret key. The existing methods that use reasonably computable decryption policies for CP-ABE, produce the ciphertext of size at least linearly varying with the number of attributes in it. This increases the number of pairing operations during decryption and leads to the computational overhead. Therefore, we aimed to propose a constant ciphertext length CP-ABE scheme with additional features viz. receiver anonymity, multi-authority, fully secure, etc. that increase the versatility of the existing CP-ABE schemes. In addition, we also apply the CP-ABE scheme to the verifiable secret sharing and onion routing algorithms to improve the efficiencies.