Cloud Computing facilitates business by storing an enormous amount of data in the cloud transmitted over the Internet with seamless access to the data and no hardware compatibility limitations. However, data during transmission is vulnerable to man in middle, known plain text, chosen cipher text, related key and pollution attack.Therefore,uploading data on a single cloud may increase the risk of damage to the confidential data. Existing literature study uncovered multiple cryptography techniques such as SA-EDS, Reliable Framework for Data Administration (RFDA), Encryption and Splitting Technique (EST) to secure data storage over multi-cloud.However, existing methods are vulnerable to numerous attacks. This article emphasis on data security issues over multi cloud and proposes a Proficient Security over Distributed Storage (PSDS) method.PSDS divides the data is into two categories; normal and sensitive, further more the sensitive data is further divided into two parts. Each part is encrypted and distributed over multi-cloud whereas the normal data is uploaded on a single cloud in encrypted form. At the decryption stage, sensitive data is merged from multi-cloud. The PSDS is tested against multiple attacks and it has been concluded that it is resistant to related key attack, pollution attack, chosen ciphertext attack, and known plain text attack. Furthermore, PSDS has less computational time as compared to the STTN and RFD encryption method. INDEX TERMS Cloud Computing, data transmission, security, cryptographic solution I. INTRODUCTION C LOUD computing environment offers enormous benefits over the local computing environment including financial cost, administrative and management overhead, adaptability, seamless office access, less memory utilization, and so on. Cloud computing provides a platform to users to utilize various assets provided on their request. Cloud computing provides adaptability by giving backup facility like Dropbox, Amazon, and Google Drive. Cloud computing also facilitates clients to cut down their expenses by providing environment for testing applications without building up a physical domain. It also provides administrative facilities, for example, Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS) [1], [2]. SaaS offers service to clients, for example, the virtual work area, webmail, and program interface. PaaS provides a stage for using programming language, administrations, libraries, and various apparatuses. IaaS offers online administrations to clients, for example, servers, load balancers, and other computing assets. Due to these reasons today businesses, organization and individual users are moving their data to the cloud.Various models of cloud such as private, public, hybrid and community cloud are defined [3] to provide various services such as infrastructure, software, and others. The security of information with overwhelming size in the cloud is a noteworthy issue. Various strategies have been proposed not only to verify information b...