In the present scenario, cloud computing is emerging as the most powerful networking as well as storage platform which is used by different users across the world.Cloud computing provides storage at free cost or at lower costs eliminating the need for costly storage and computational resources. So large amount of data is being stored and a lot of computations are being performed in the cloud. When different kinds of operations are performed in the cloud we must consider the security of the cloud environment. Cloud security is a major concern nowadays a lot of confidential data is being uploaded on to the cloud.
Even though the cloud stores the data at low costs it allows its resources to be shared among the users and individuals, servers and thereby all the files are vulnerable to the attackers causing a major threat. The other security issues include data confidentiality and data integrity. Data Confidentiality means the data should not be disclosed to the un-trusted users and data integrity means that data should not be altered before being processed by the server.In recent years the concept of cryptography has cleared most of the security issues providing data confidentiality and integrity.
There are also many security concerns even in the concept of cryptography based on the encryption algorithms. There are two types of encryption algorithms. They include symmetric encryption algorithms and asymmetric encryption algorithms. Symmetric encryption algorithms maintain only one key and it is used to both encrypt and decrypt. Whereas asymmetric encryption algorithms have two keys public and private. Symmetric encryption is used to protect the message and is faster compared to asymmetric encryption.But the only disadvantage is that it uses only a single key. We consider key length as one of the most important factors while selecting the symmetric encryption algorithm. This is because if the key length is large, it is difficult for the attacker to guess the key and thereby improving security.DES is the weakest encryption with the key length of just 56 bits. So it is improved and proposed as a new encryption algorithm Triple DES with the key length of 168 bits.AES and blowfish are the other stronger encryption used in the paper to improve the security by randomly allocating the three algorithms to the files by which makes it difficult for the attacker to guess the algorithm.
The redundant storage of the files in the cloud is also one of the most prevailing problems which consume a lot of storage space. This can be eliminated by using the concept of de-duplication which do not allow the duplicate files into the cloud.