Proposed Secure Cloud Data Storage Client Computer Science Essay

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The two biggest concerns about cloud storage are reliability and security. Clients arent likely to entrust their data to another company without a guarantee that they'll be able to access their information whenever they want and no one else will be able to get at it.

To secure data, most systems use a combination of techniques, including:

Encryption, which means they use a complex algorithm to encode information. To decode the encrypted files, a user needs the encryption key. While it's possible to crack encrypted information, most hackers don't have access to the amount of computer power they would need to decrypt information.

Authentication processes, which require to create a user name and password.

Authorization practices -- the client lists the people who are authorized to access information stored on the cloud system. Many corporations have multiple levels of authorization. For example, a front-line employee might have very limited access to data stored on a cloud system, while the head of human resources might have extensive access to files.

Blowfish is a block cipher proposed by Mr. Bruce Schneier, deploy some software. It can be just as DES and 3DES, a 64-bit, except with the block size, using the huge key, Blowfish is considered safe. Efficient in software, platform performance will depend on how the cache memory and should be handled.

• AES is the successor of DES as a standard symmetric encryption algorithm for agencies of the U.S. Federal Government. Accepts keys of 256-bit (128-bit is not already very broken) of 128, 192, or, to use (so no problem there) 128-bit block, in terms of both software and hardware, AES is efficient is. It was selected through a public offering, including hundreds of cryptography researcher for several years. Basically, it cannot be better than that. So, when in doubt we use AES.

The box encryption (128-bit chunks of data using AES), "block" block cipher. The message needs to be divided into blocks, a way to do the division, if you want to encrypt a "message" cannot might longer than 128 bits is called the mode of the "chain" and the actual operation. Called naive mode (simple division), the ECB, have a problem. Also use a block cipher, and is not easy to successfully, for example, it is more important than the choice between or 3DES AES.

4.2 The Blowfish Encryption Algorithm

Blowfish Encryption is one of safest way to transmit your passwords, secret answers and credit card numbers, etc. It uses 1 to 448 bit key length and has a block size of 64 bit. The encryption is considered safe in many ways mainly due to its slow computation due to the key encryptions and thus avoids any automatically generating software attacks. Blowfish Encrypt and Decrypt How does it real time woks:

Plain / encrypted text : password

Result encrypted text

Result decrypted text




Table no 4.3.1: Encrypt and Decrypt password with Blowfish Encryption Algorithm

As a plain text is 123456 after encrypted it is 5130E2D58165B07C0F76C098D2071580

And after decrypted text is ¯£ÊPcµÆ’±

Encryption is very secure and there has been no publicly known cryptanalysis of it to date, making it one of the strongest and most secure techniques of encryption. Pre-processing of plain text of a size as large as some four kilobytes is required for every new key to be used in encryption and it explains the amount of security attained as a result. It has been popular mainly due to its free use as it was not patented by its designer. It occupies a very small size of just four kilobytes of RAM and hence can be used on the oldest desktops and other devices.

4.3 Client-side encryption

Data encryption: SESS encrypts the files locally, so that any online storage can be used even for sensitive data.

The server requests encrypted data To browser

The anchor part of the URL (# key)is The decryption key, never sent to server.

In the browser Data is decrypted using the key labeled.

Figure No 4.4.1: Client-side encryption Method

The encryption storage method based on client data is predictable, traditional encryption system the main idea is to encrypt the data before storing to protect user data privacy effectively. When storing data, user first encrypts the data then stores the data in the cloud. At data access, user reads data directly from the cloud then decrypt the data.

Data storage Based on client data, how to store encrypted Conventional method of encryption storage is a traditional encryption scheme based on the client data. In order to protect the user's data privacy effectively, the main idea is that before storing, encrypting the data. Data when storing the data, the user is first encrypted and stores the data in the cloud. At the time of data access, the user reads the data directly from the decoded data cloud.

Retention method for encrypting customer data based on a conventional, traditional encryption system idea is to encrypt the data before storing to protect the user's privacy effectively.

When storing data, you first encrypt the data, and then stores the data in the cloud. Access to the data, the user reads the data directly from the cloud then decrypt the data.

4.4 Secure Cloud Data Storage Client-side encryption Method

Figure 4.5.1: Proposed Secure Cloud Data Storage Client-side encryption Method

Firstly, user encrypts the data then put them in the cloud the specific steps are shown in figure 4.4.1.

Step 1: The client receives the cipher text by encrypting the data to be stored in the cloud.

Step 2: The client interacts with the meta-data server, the meta-information (size, etc) the cipher text meta-data server. Then allocates meta-data server storage space and come back on the metadata back to the client.

Step 3: With the metadata from the meta-data server, the client will connect to the corresponding block data servers, to establish a reliable channel and the data to send data blocks for storage servers.

The client reads the data directly from the cloud, and then decrypts the cipher text from the cloud. The specific steps are shown in Figure 4.4.1.

Steps 4: access encrypted storage method based on data client

The analysis is to protect the privacy of client data In storage based encryption method, encrypted data in the cloud. The privacy of the data is achieved through the encryption algorithm. Encryption algorithms able to fully guarantee their privacy in modern cryptography. Without the right information is key, even if someone gets the cipher data, it would not leak user data. As a result, the storage method is based on the clients' data encryption to protect the privacy of user data in the cloud. But if the data is much more, it costs such a long time encrypting the data, cause hinder performance and a very bad impact on the efficiency in reading and writing.

4.5 Contribution for Proposed System

STM E-Storage Service provides for personal data users with the proxy unstructured data access on any device, the file data is stored elsewhere. Based on the popular E-STM storage service, STM E-Storage Service acts as both a local repository file and proxy file. The file repository, just install the preferred storage device for STM E-Storage Service, a flexible architecture and the content will be immediately available for users to sync and share files. You can add other storage devices locally or via NFS, CIFS, and even other cloud storage. STM E-storage service flexible plug-in architecture allows you to connect to the right magazine for user and other's needs.

More than just a simple repository synchronization of files and share STM E-Storage Service can also be used as a proxy server to access the file by combining multiple storage locations into one common interface STM-the E-Storage Server Service. This provides one central, controlling, and auditable location for client access to any file on the server, with the appropriate backup and redundancy.

Access to all important matters are not always locked and can be opened easily at the time of urgency. The advantages of proposed system are that security is maintained in the new system. Securities for all important data are maintained confidentially. As it is easily understandable and user friendly, quick entries can be made in this system.

4.6 Incorporate Blowfish algorithm in proposed system

Crypt Blowfish allows for encryption and decryption on the fly using the Blowfish algorithm. Crypt Blowfish does not require the mcrypt PHP extension, it uses only PHP.

Crypt Blowfish support encryption/decryption with or without a secret key.

In our proposed system usage:

$bf = new Crypt_Blowfish('some secret key!');

$encrypted = $bf->encrypt('this is some example plain text');

$plaintext = $bf->decrypt($encrypted);

echo "plain text: $plaintext";

4.7 Pseudo code for Proposed System

PROCEDURE login user against STMESS

CALL the web service for authentication USING username, password


PROCEDURE login user against STMESS

ARGUMENTS username , password

IF username and password are not empty THEN

CALL the web service for authentication USING username, password


SHOW an error message



IF READ username, password then the login form is displayed

Else if upload file has been submitted, then

Check if the user that was entered is valid

If the user is valid, then the user has uploaded the file

Else if store file has been submitted, then

if the user is valid, then the user has stored the file

Else if delete file has been submitted, then

if the user is valid, then the user has deleted the file else if the user isn't valid, then

Display any necessary errors

Display the login form again



4.8 Conclusion

STM E-Storage Service is a software suite that provides a storage area that does not depend on the location of the data (cloud storage). It can be installed on the server of the private at no additional cost. So, anyone sensitive to the privacy of their own data. Your files will remain secure on the server. All files are stored on the storage server electronic STM is so even that is not an administrator in a state in which to enable encryption application, it is encrypted password you can see the inside of the file . Add the SSL connection, the time during exercise and rest, your files are safe. Data privacy protection Proposed method Server side encryption of files. DEPRECATED. Only enable this features if you want to read old encrypted data. Warning: You will lose your data if you enable this App and forget your password.