Research On EHR Access Control Scheme Based On Attribute-Based Encryption In Cloud Environment

Cloud computing provides EHR system with fundamental resources of storage and computing.However,security and access control scheme have become a major concern when data stored in cloud.Focusing on the security problems,a dynamic trust-level based access control scheme on EHR was proposed.It supports basic security standard and flexible access control strategy along with powerful storage and computing ability cloud computing gives.Security and performance analysis shows that,this scheme will improve access control efficiency on EHR system.The main work is listed as follows:(1)A trust-level based CP-ABE scheme was proposed.A “Trust level” attribute was defined to indicate user's trusted level and divided users into different classes,which was attached to the ciphertext.Our system would give different response according to different “Trust level” a user had.Like IBE,User with high “Trust level” was be able to use this attribute as an identity to obtain the key and decrypt the message in a constant time.On the contrary,User with low “Trust level” was denied any further interaction,which garenteed the security while decreaseing unnecessary lost.The rest ones would decrypt the message according to basic CP-ABE scheme.(2)A CP-ABPRE based trust-level protection scheme in dynamic environment was proposed,which focusing on solving the problem of policy updating.The updating algorithm uses proxy to re-encrypt the ciphertext instead of decrypting it.Also,we combine this scheme with trust-level attribute which is attached to the ciphertext and user with high trust-level would be able to decrypt the message efficiently.Finally,to prevent the disclosure of trust-level attribute,we perform a transformation before submitting one's trust-level attribute and recover it before decryption.(3)Combining these two schemes as well as concerning real-world demand of EHR system,a dynamic trust-level based access control scheme on EHR was proposed.This scheme satisfies the dynamic demands in reality.Finally,the full text is summarized and the future research direction of the EHR access control scheme in cloud environment is analyzed.