One of the most promising encryption techniques for secure data sharing in the field of Cloud Computing is Ciphertext-Policy Attribute-Based Encryption (CP-ABE).This encryption technique has turned to be an important encryption technology to tackle the challenge of secure data sharing. In this encryption technique, Users’ private keys and cipher texts are associated with a set of attributes. This technique completely encrypts the file and does not have any control over the individual attributes in the file. So, in order to overcome this problem a concept called attribute with weight was introduced, so that it can have control over the individual elements in the file and can be able to hide sensitive information while sharing data with the users. But the problem of malicious cloud insider still persists. Imagine the context of a online health records system. An authorized user can access the health record by satisfying their arbitrary constraints defined by the data owner. Once they get access to the data, the system cannot prohibit or monitor their valid usage of the data. So we design an Embeddable Digital Signature algorithm that can embed the accessing users credentials in each health record they access which has a stealth effect of catching and prosecute them in case of an unauthorized data breach. Hence, the resulting scheme becomes more secure.
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