1.1 Background
Nowadays due to recent technological development, the amount of data generated by internet, social networking sites, sensor networks, healthcare applications, Banking Sector and many other companies, is drastically increasing day by day. All the enormous measure of data produced from various sources in multiple formats with very high speed (Bagheri & Jahanshahi, 2015) is referred as big data. The term big data (Bosch et al, 2014; Chan, 2009) is defined as “a new generation of technologies and architectures, designed to economically separate value from very large volumes of a wide variety of data, by enabling high-velocity capture, discovery and analysis”.
From this definition, we can say that big data are reflected by 3V’s, which are, volume, velocity and variety. A common theme of big data is that the data are diverse, i.e., they may contain text, audio, image, or video etc. This big data is stored on cloud and to attain the big data security over cloud computing, the mono encryption technique is not adequate. Because of the voluminous architecture of cloud computing system, the traditional data security systems are not adequate to provide the complete security solution.
During mobile communication, the encryption and decryption facilities are harder to implement. Clouds can work in collaboration, even if they have their own security features. Therefore, without modifying the sequence of the encryption process, the parallel and distributed encryption facilities will be available at every cloud during surfing from cloud to cloud. Every cloud manages the essential resources and allocation can be done on every request of the resource while user moves from one cloud to another. The major issues when dealing with the cloud computing system is the network and resource availability. If the resources are not allocated during cloud computing, the encryption and decryption cannot feasible and can be difficult to pursue. The cloud collaborative encryption is a technique where, various clouds can work concurrently with distributed processing facilities. Here, the security can be enhanced by implementing the homomorphic encryption.
Data communication plays a vital role for every individual or organization all over the world. Every organization completely relies on the day-to-day data processed by their systems. Massive amount of data transferred from one location to another, contains the confidential information and must be protected from the various potential attacks occurring during network communication. Recent advances in the information technology offered new business, personal, social, educational, research opportunities to everyone.
Cryptography is the science of “Secret Writing” that helps the trusted secure communication over the non-trusted communication channel. Encryption is a technique through with the confidential data can be secure by applying the specific encryption algorithm with a combination of a key. Decryption is a technique that reverts, or extracts the original data only using the valid key used for encryption.
Encryption is used in two ways such as; one-way encryption and two-way encryption. One-way encryption is used to encrypt the unique key used for encryption and decryption to enhance the security of the key itself. This encryption key is only used for encryption and decryption of valuable information. The key itself is not required to decrypt and is worthless. Two-way encryption technique is used to encrypt the valuable information flows over the communication channel and need to protect from the potential network attacks. This encrypted information is then decrypted to get the original information. Encryption is done with the help of single and multiple keys i.e. symmetric key and asymmetric key. The symmetric key encryption is a technique where the same key is used for encryption and decryption of the original message. In case of asymmetric key, different keys are used to encrypt and decrypt the original message. Figure 1 depicts the basic encryption and decryption mechanism.