Data Security in Cloud Computing Using Steganography: A Review

Cloud computing is one of the largest developments in the field of information technology during recent years. It is a service oriented computing which offers everything as a service via the internet by the pay-as-you-go model. It becomes more desirable for all organizations (such as education, banking, healthcare and manufacturing) and also for personal use as it provides a flexible, scalable, and reliable infrastructure and services. For the user, the most important issue is to store, retrieve and transmit the data over the cloud network and storage in a secure manner. Steganography and cryptography are some of the security techniques applied in the cloud to secure the user data transmitting. The objective of steganography is to hide the existence of communication from the unintended users; whereas cryptography encrypts the data to make it more secure. Steganography is considered as the most effective technique for securing the communication in the cloud. Digital images are most commonly used as a cover medium in steganography. In the literature, there exist several image steganography techniques for hiding information in images; which were developed and implemented in the time domain as well as in the frequency domain. Fundamentals of spatial domain and frequency domain techniques are reviewed in this paper with emphasis on the Least Significant Bit (LSB) and the Discrete Cosine Transform (DCT) techniques.