# Security Enhancement for Data Migration in the Cloud
## 3 Existing Solutions and Prior Works  
Protect data outsourced in the cloud has always been the biggest challenge for IT providers and academia to promote cloud adoption. Pick up any IT magazine or browse almost any social media site or IT blog, and you will be sure to see talk about data security and privacy. More and more people are complaining about personal data breach, and enterprises as well recognize that it is critical to move sensitive data in the cloud without knowing the appropriate security control put in place. These days, numerous vendors and cloud providers are leveraging cloud-based storage models to deliver their security solutions known as Security as a Service (SecaaS). It is likely for any other cloud services that the SecaaS model embraces all of the characteristics of cloud computing and it provides to users less or no control over services and tasks. The Cloud Security Alliance (CSA) has identified some services offered by SecaaS [10]--among them is Encryption as a Service. According to some providers such as Amazon Web Services (AWS) and Dropbox, Encryption as a service is the most obvious way to keep data secure in the Cloud environment [11]. For instance, AWS offers a flexible and scalable layer of security for data stored in the cloud by providing several options for encrypting data at rest-ranging from completely automated AWS encryption solutions to manual and client-side options; however, in reality, they don't provide on-premises key management controls and data access policy option for EC2 and EBS data [12]. SecaaS offerings can take many forms causing market confusion and complicating the selection process. Customers are increasingly faced with evaluating SecaaS solutions, which do not run on premises, and they need a better understanding of these offerings to assess the type of security issues they address and also to evaluate the security risks and the shared responsibility for the security of systems for which they are accountable. Even though CSPs claim that customer data is well safe and secure, we know, from reports [13] of cloud leaks on celebrities and companies, that there is no complete guarantee of safety when storing sensitive data in the cloud environment unless consumers approach cloud in the right way, with the correct checks and balances to ensure that all security and risk management measures are covered. In addition to SecaaS, academia and industry have developed a lot of research works and practical approaches to secure cloud data storage. Many recent proposed models are based on cryptographic algorithm [14; 15; 16; 17] such as DES, AES and Elliptic curve cryptography (ECC). Therefore, to ensure the secrecy of data before migrating in the cloud, some methods relied upon data encryption by crypting data using AES-128, 192, 256 bits, depending on the file size and data format [17]. 128 and 192 bits key encryption are suggested to users to encrypt, respectively, large and medium data files. However, encryption with 256 bits key will be done on small data files, but based on the data format rather than its size. Another approach is to combine Encryption and Obfuscation [18; 19]. Encryption is done on alphabets and alphanumeric type of data, and obfuscation only to the numeric type of data [18]. Specifically, encryption helps a user to provide secrecy to its data when it is transferred in the network, and data obfuscation helps the service provider to secure the user's data at rest [19]. This model provides an improvement of data confidentiality. Secure personal cloud storage system that affords the plug-n-play convenience of portable storage device (PSD) is highlighted [20]. Authors proved, the accessibility and scalability of cloud storage, using the information dispersal algorithm (IDA) to address the dual requirements of data confidentiality and availability. Their implementation allows for slices files to be spread across multiple CSPs. Therefore, the adversary will need to compromise at least two over three cloud providers to be able to reconstruct the data.