This paper presents a multi-authority attribute based encryption (ABE) scheme that allows any polynomial number of independent authorities to monitor attributes and distribute secret keys. The scheme enables encryption such that a user can decrypt a message only if they have at least d_k attributes from each authority k. The scheme can tolerate an arbitrary number of corrupt authorities and guarantees security as long as the required attributes cannot be obtained exclusively from those authorities and the trusted authority remains honest. The authors also show how to apply their techniques to achieve a multiauthority version of the large universe fine grained access control ABE scheme presented by Gopal et al. The scheme is proven secure in the selective ID (SID) model, relying on the bilinear Diffie-Hellman (BDH) assumption. The paper also discusses the challenges and techniques involved in constructing a multi-authority ABE scheme, including preventing collusion between users and authorities, and the use of pseudorandom functions (PRFs) and a central authority to ensure security and correctness. The scheme allows for dynamic attribute changes and is designed to be efficient and secure against various attacks.This paper presents a multi-authority attribute based encryption (ABE) scheme that allows any polynomial number of independent authorities to monitor attributes and distribute secret keys. The scheme enables encryption such that a user can decrypt a message only if they have at least d_k attributes from each authority k. The scheme can tolerate an arbitrary number of corrupt authorities and guarantees security as long as the required attributes cannot be obtained exclusively from those authorities and the trusted authority remains honest. The authors also show how to apply their techniques to achieve a multiauthority version of the large universe fine grained access control ABE scheme presented by Gopal et al. The scheme is proven secure in the selective ID (SID) model, relying on the bilinear Diffie-Hellman (BDH) assumption. The paper also discusses the challenges and techniques involved in constructing a multi-authority ABE scheme, including preventing collusion between users and authorities, and the use of pseudorandom functions (PRFs) and a central authority to ensure security and correctness. The scheme allows for dynamic attribute changes and is designed to be efficient and secure against various attacks.