Research And Implementation Of Data Security Protection In Mobile Cloud Environment

Today,mobile smart devices and wearable equipments with convenient network access and portability have become an essentials of our lives and are widely used in health tracking,mobile payments and E-commerce,etc.In cloud environment,data outsourced to cloud storage server,mobile devices can easily access the data on the cloud via mobile network.Yet,cloud service is not full trusted.There may be attacks from inside or outside the cloud server.Due to the user's loss of direct control of outsourcing data,they tend to encrypt the data first before uploading it to the cloud server.In the case where the data needs to be shared to multiple users,traditional one-to-one encryption can result in significant key management costs or multiple ciphertext copy costs.The attribute-based encryption,one of modern cryptography,allows flexible one-to-many encryption without prior knowledge of who will be receiving the data.Existing attribute-based encryption schemes are based on bilinear pairing algorithm,and the complexity of the ciphertext is linearly related to the number of attributes in the system.This makes the encryption and decryption algorithm of the attribute-based scheme consume massive resources,and limits its deployment on mobile devices.At present,there are relevant studies trying to break the limitation of attribute-based encryption,including the online/offline and outsourcing decryption technology.The online / offline technology aimed to divide the encryption operation into two sub-steps.When the device is offline(idle or charging),most work of the encryption is preprocessed,and only a very simple algebra is needed to encrypt the data online.The outsourced decryption aimed to outsource the major computational tasks in the decryption to the cloud server.This article integrates the outsourcing decryption into an online / offline scheme,then a hybrid scheme for resource-constrained mobile devices is obtained.The definition and proof of selective CPA secure is given for this scheme.Then a secure mobile data sharing system is designed and implemented using the JPBC cryptographic library and this scheme.The system uses the attribute-base encryption to securely exchange private information between the mobile devices and the cloud server.Performance analysis shows the availability of the scheme in practice.