Cloud storage is widely used for sharing data due to low cost maintenance. But, it is also necessary to secure data on cloud. Secure Data Sharing in Cloud focuses mainly on: a) privacy and confidentiality, b) key management and encryption, c) secure data sharing without re-encryption and d) forward and backward access control. When user wants to share data, it sends request to trusted party that generates a symmetric key which is used to encrypt the data for sharing. This key is used to compute two key shares for trusted party and user. The key is deleted using secure overwriting. Its working was formally verified using High Level Petri Nets, SMT Library, and Z3 solver. It was implemented in Visual Studio and its performance was evaluated based on time consumption for various operations which revealed that it has the potential to be effectively used for secure data sharing in cloud.