This project presents a novel pairing-free revocable certificateless encryption scheme integrated with ciphertext evolution tailored for secure healthcare systems. The design leverages the AES cryptographic algorithm to ensure data confidentiality and integrity throughout the data lifecycle. The system comprises four main modules: Data Owner (Patient), Key Generator, Cloud Server, and Data Receiver (Doctor). Patients can securely register, login, upload data, and view treatment plans provided by authorized doctors. The Key Generator module is responsible for securely generating cryptographic keys without relying on traditional certificate authorities. The Cloud Server stores encrypted data and allows authorized access while preserving privacy. Doctors, as data receivers, register and login to access, decrypt patient data using keys generated by the Key Generator, and provide appropriate treatment plans. This architecture ensures secure data sharing, revocation capabilities, and dynamic ciphertext updates, addressing critical privacy concerns in healthcare data management. The proposed system enhances confidentiality, reduces dependency on trusted third parties, and supports flexible data access control, making it suitable for modern healthcare environments.

Keywords:

Certificateless Encryption, AES Algorithm, Healthcare Data Security, Ciphertext Evolution, Data Privacy, Key Generation, Cloud Storage, Revocable Encryption, Secure Data Sharing, Patient-Doctor Communication.