This scheme stores data at cloud data storage centers within edges of color ... In this paper, we proposed a good data hiding scheme to ensure security ... storage.we enhanced the security of data by using encryption methods and then.
Increasing Security for Cloud Computing By Steganography in Image Edges Abstract In cloud computing the security of data storage is an important issue because the entire data reside over a set of interconnected resource pools that enables the data to be accessed through virtual machines. It moves the application software’s and databases to the large data centers where the management of data is actually done. As the resource pools are situated over various corners of the world, the management of data and services may not be fully trustworthy. So, the privacy and security of data is highly challenging. To ensure privacy and security of data-at-rest in cloud computing, we have proposed an effective and approach to ensure data security in cloud computing by means of hiding data within images which is called steganography. The main objective of this paper is to prevent data access from cloud data storage centers by unauthorized users. This scheme stores data at cloud data storage centers within edges of color images and retrieves data from it when it is needed. Index Terms— Cloud Computing , Data Storage Security, Steganography , Edges of image.
زيادة األمن للحوسبة السحابية من خالل إخفاء المعلومات في حواف صورة الخالصة يعطي هذا البحث نظرة معلوماتية عن اهمية زيادة أمن المعلومات المتواجدة في مراكز خزن البيانات في زيادة االمنية من خالل. االستخدام الغير مخول, التعديل, السحابة الحاسوبية كونها معرضة الى السرقة بناء نظام برمجي يقوم بإخفاء المعلومات الحساسة في حدود صور ملونة بشكل عشوائي قبل ارسالها الى مركز خزن البيانات في السحابة الحاسوبية وباإلمكان استرجاعها عند الحاجة فقط من قبل الشخص .المخول الذي يعرف اماكن خزن المعلومات في حدود الصورة . حدود الصورة، الكتابة المخفية، امنية مخزن البيانات، السحابة الحاسوبية: الكلمات المفتاحية 1
Introduction Cloud computing is a very popular. But still involving paradigm [1]. cloud computing is a model for enabling convenient, on demand network access to a shared pool of configurable computing resources (e.g. , networks, servers , storage , applications, and services ) that can be rapidly provisioned and released with minimal management effort service provider interaction [2]. Cloud computing allows customers of cloud providers to avoid- startup costs or reduce operating cost [1]. The biggest issue in the cloud computing is its data security [3]. Data must be secured during all processing stages including: storing ,processing , uploading [4]. When our data is present in some one's server there is a big chance of our data is hacked [3]. Users can store their huge amount of data in cloud data storage centers. But many clients are not ready to implement cloud computing because the lack of proper security control policy and weakness in protection of data which leads to a big challenge for the cloud computing providers[5]. Secure data transformations on Internet has been a dream since the emergence of Internet[6]. In order , to make our data secured in cloud platform the best idea is to hide data in image , Audio , video . by using Steganography concept [3]. In this paper, we proposed a good data hiding scheme to ensure security transmit data and increase the security of data when it is residing in the cloud data storage.we enhanced the security of data by using encryption methods and then hide it into edges of gray image. And we increased the security of data by hide gray image (steg) in another color image. When these color images are stored in cloud data centers , no one can view the original content (secret message) of the data by unauthorized Parties.
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Cloud Computing Definitions What is a Cloud ? The term cloud refers to a network or internet. the other words , we can say that cloud is something which is present at remote location. What is a Cloud Computing ? Cloud computing refers to manipulating, configuring and accessing the application online. Cloud Computing offers online, data storage ,infrastructure, and applications [7]. How Data is Stored in Cloud ? Storing a data on the "cloud" means remote storage of data cloud storage is a model of internet based services provided to the user on demand. Client uses the client computer to connect to the storage (data base) with the help of a web service. With the help of this, the client can upload / download his data to or from the storage space allocated to the user by the cloud provider shown figure [1]. Cloud storage system architecture includes a master control server and several storage with the node controller, if details are found correct it allows user to manipulate his data storage [8].
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Cloud Computing Benefits User of a cloud access cloud services through internet by the help of a web browser. Cloud services do not need to buy any software to get the benefits of software. A simple example of cloud computing is yahoo email ,Gmail, Hot mail, etc. you do not need software or server to use them. Each customer would need is just an internet connection and the customer can start sending emails. The server and email management software is all on the cloud (internet)and totally managed by the cloud service provider yahoo, Gmail , etc. [8]. Could computing has numerous advantages , some of them listed below[7][9]: 1. One can access application as utilities ,over the Internet. 2. Manipulate and Configure the application online at any time. 3. Reduce the cost and complexity of owning, computers and networks. 4. Make use of new innovations. 5. Flexible use. 6. Rapid deployment. 7. Scalability. 8. Reliability. 9. Efficiency. 10. It does not require to install a specific piece of software to access or manipulate cloud application. 11. Cloud resources are available over the network in a manner that provides platform independent access to any type of clients. 12. Cloud computing offers on-demand self-service. The resources can be used without interaction with cloud service provider(CSP). 13. In addition, information in the cloud is not as easily lost (when compared to the paper documents or hard drivers ,for examples).
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Cloud Architecture Cloud Computing Model is composed of three service models, and four deployment models: First - Service Models: cloud computing including three types of services listed as follows: shown figure (2). 1) Software –as- a- Services (SaaS) SaaS is software that is owned, delivered and managed remotely by one or more Providers [9]. SaaS, provides the use of applications running on the cloud provider's infrastructure [4]. SaaS model allows to use software applications as a services to end users[7]. 2) Platform - as - a - Service (PaaS) In PaaS, an Operating System, Hardware ,and Network are provided , and the customer installs or develops its own software and application [9]. PaaS provides the runtime environment for applications, development and deployment tools, etc. [7]. 3)Infrastructure- as- a –Service (IaaS) IaaS provides access to fundamental resources such as physical machines, virtual machines, etc. This provides the customer the capability to provision processing, storage , networks , and other fundamental computing resources[4].
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Second- Deployment Models: there are four primary cloud deployment models listed as follows [4][7] [9]: 1) Public Cloud: The public cloud allows systems and services to be easily accessible to the general public. It may be less secure because of its openness. Examples, online photo storage services, e-mail services. 2) Private Cloud: The private cloud allows systems and services to be accessible within an Organization. It offers increased security because of its private nature. In a private cloud , the cloud in infrastructure is operated solely for a specific organization, and managed by the organization or a third party. 3) Community Cloud: the community cloud allows systems and services to be accessible by group of organizations. 4) Hybrid Cloud: This model employs aspects of all other cloud models and is the most commonly found cloud deployment model used within large organization. The hybrid cloud is mixture of public and private cloud. The critical activities are performed using private cloud while the non-critical activities are performed using public cloud. Security of Cloud Computing Main challenge of the cloud computing is to provide security to cloud computing. The main aim of security is to provide availability , confidentiality , and integrity to the data. There are many risk associated with the cloud network such as[10]: Data can be hacked by an unauthorized person. Data can be changed by third party while transferring the data. New threats are introduced when an organization moves its critical data and applications to a cloud storage server, new mechanisms for security data in the cloud must be implemented. There are several security threats to cloud computing are listed below [4]: 1. Abuse and nefarious use of cloud computing (IaaS , PaaS). 6
2. Insecure interfaces and Application Programming Interface(API) ( IaaS ,PaaS, SaaS). 3. Malicious insiders ( IaaS ,PaaS, SaaS). 4. Shared technology issues (IaaS). 5. Data loss and leak age ( IaaS ,PaaS, SaaS). The following new security and privacy challenges are the most important: Ensuring authorized access to user data. Both cloud provider and its customer should share responsibility for privacy and security [11]. When data is travelling over the Internet ,and is store in remote locations. In addition, cloud providers often serve multiple customers simultaneously. All of this may increase the scale of exposure to possible breaches. Another risk in data storage centers that cloud computing may use "function creep" of data by cloud providers that were not expected when the information was collected[9]. There are several security issues for cloud computing technologies including : networks, databases, operating systems, resource scheduling, memory management, and concurrently control. There are six specific areas of the cloud[12] : 1) Security of data at rest. 2) Security of data in transit. 3) Authentication of user / applications /processes. 4) Robust separation between data to different customers.
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Cloud legal and regulatory issues. There are key mechanisms for protecting data such as : o Access Control. o Auditing. o Authentication. o Authorization. In finally , we can summarize the steps for access to cloud storage system; listed below[7]: when the client issue request to access data : 1. The client data request goes to proxy ,s external service interface. 2. The proxy forwards the request to the broker. 3. The broker requests the data from cloud storage system. 4. The cloud storage system returns the data to the broker. 5. The proxy sends the data to the client. All steps above are shown in figure(4).
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Cloud Computing & Information Hiding We are planning to increase the confidentiality , privacy, and availability of data present in cloud. Internet users frequently need to store, send or receive private information. The most common way to this is to transform the data into a different forms. The resulting, data can be understood only by those who know how to return it to its original form. This method protecting information is known as encryption. Cryptography is the science of using mathematics to encrypt and decrypt data. It enables you to store sensitive information or transmit
it across
insecure
channels or networks (like the Internet) so that it cannot be read by anyone except the intended recipient.
Figure(5 ) How does cryptography work 9
The major drawback to encryption is that the existence of data is not hidden. data that has been encrypted although unreadable still exists as data, if given enough time ,someone could eventually unencrypt the data. A solution to this problem is steganography [8]. Steganography is the art and science of hiding information into covert channels so as to conceal the information and prevent the detection of the hidden message. Show the figure (6 ).
Figure (6 ) How does Steganography work
Steganography is data hidden within data. It works by replacing bits of unused data(redundancy) in computer files (such as graphics , sounds, text, video, ete ) with bits of secret message show figure (7). Steganography is the best option for storing, sending ,information secretly because it hides the existence of secret message and provides more security[6]. All digital file formats can be used for steganography , but the formats that are more suitable are those with high degree of redundancy. Redundant bits of an object are those bits that can be altered without the alteration being detected easily [3]. Steganography is considered as a way to enhance but not to replace encryption [4]. Steganography message may first be encrypted ,then a cover file is modified to contain the encrypted message, resulting in stegocover. Only those who know the technique used can extract the message and then need to decrypt it.
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The best carries for steganography must include two features; it should be popular and modification of the carrier related to inserting the secret data should not be visible to third party[13]. There are several approaches in classifying steganographic techniques. The classification according to the cover modifications are : Substitution Techniques : These methods range from LSB coding. Basic substitution systems try to encode secret information by substituting insignificant parts of the cover by secret message bits. The receiver can extract the secret information if the positions secret information is acknowledged. Transform Domain Techniques : These methods are represented by Discrete Cosine Transform (DCT) , Discrete Wavelet Transform( DWT), or others. In DWT , the standard technique of storing in the LSB is still applied , but the only difference is that the information is stored in the wavelet coefficients of a cover, instead of changing bits. Statistical Techniques : The statistical approach is based on a pseudo random, statistical process that takes advantage of the human weakness to luminance variation. This method is more robust to image processing such as cropping and rotating. In this paper we used Substitution Techniques : These methods range from LSB coding. LSB is One of the most popular amplitude modification methods is known as Least Significant Bit (LSB) insertion , it is common and easy to apply in both steganography and watermarking. As the name states, the information is encoded into the least significant bits of the cover file. In this technique LSB of binary sequence of each sample of digitized cover file is replaced with binary equivalent of secret message.
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Proposed System The security system which is used is image steganography as image are the most popular because of their frequency on the Internet. So, we focus to increase security during transmission and store the data to/in cloud storage data. Our proposed model aims to secure data-at-rest, by hiding secret data within some color images. This underlining concept is known as steganography which tells- “The art and science of writing hidden messages in such a way that no one except the sender and the intended recipient, suspects the existence of the message, a form of security through obscurity”. To ensure the security for cloud data storage from unauthorized users, we have designed efficient mechanism for data-at-rest in cloud data storage centers. As our used techniques hiding secret data within digital image, this steganography technique exploits the weakness of Human Visual System (HVS). HVS cannot detect the variation in luminance of edges of images. An image is a collection of pixels (Picture Elements), where each pixel of color image is composed three bytes RGB :Red, Green, and Blue; each one has 8 bits. If we change the last bit, the color information may be varying within +1 to -1. This change of the intensity will not be perceived by human eye. User makes his secret data within edges of image cover and the file generated is cut into data-blocks that are divided into pieces of equal size, these pieces are loaded computing. In this paper , we
in cloud
used Robinson Mask with LSB method to
hide secret information into edges of cover images and then sending these images to storage area in the cloud computing. In this method ,we hide one bytes of secret message in one pixel of edges of cover by hide 3-bits of the byte of message in 3-LSB of Red byte of edges of cover ,hide 3-bits of the byte of message in 3-LSB of Green byte of edges of cover , and 2-bits of the byte of message in 2-LSB of Blue byte of edges of cover. 12
Figure (8) Hidding Process
(( Hiding Algorithm 1 )) The LSB algorithm embeds secret message data in cover image through manipulation the cover by using Robinson Compass filter to detect edges of the image and selected these edges in array as pixels. Embedding Process will be described by the following algorithm and block diagram: Step 1: Read the secret data. Step 2: determine the size of secret data file, and give the length of secret message as bytes. Step 3: Load the cover image. Step 4:Copy the first 54 bytes (header)of cover image and write it in a new stego file. Step 5: Find the edges of image by using Robinson Compass filter specially to select edges of image. Step 6: Compute the number of pixels of selected edges. And store the positions of these pixels in array(x,y). And Step 7:Create new Random array corresponding the array of the positions of pixels. Step 8:Select the position of edges according to the random array. Step 9: While not end of secret message file : Read secret message file bytes sequentially. And convert to binary form. Step 10: Hide first character(byte) of message into a pixel of edges of cover which selected by random array ; Put first 3-bits of message byte instead 313
LSB of red color byte , and Put next 3-bits of message byte instead 3- LSB of green color byte , and Put last 2-bits of message byte instead 2- LSB of blue color byte in sequentially. Step11 : Repeat step 8 until while condition is satisfied. Step 12: Take the complete cover file as a stegocover file. LSB embedding Process of edges of image
can be clarified
in block
algorithm(1). Input :-Cover file , secret message file. Output :- Stegocover file. { While not end of secret message file { Read secret message file byte sequentially Convert to binary form { While not end of cover file Read edges of cover file as pixels Put pixels in array. Create random array of position. Read an edges pixels as a bytes sequentially. } Put first 8 bits of secret data instead last of 3-bytes of first pixel according to random array of position. } Repeat until while is satisfied. Take complete cover file as a stegocover file. }
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(( Retrieving Data from Image Algorithm 2 )) When an authorized user wants to view data which are already stored in remote cloud servers within images, the following mechanism helps us to retrieve data. Extracting Process will be described by the following algorithm(2) and block diagram(2): Step 1: Read the stego file, Compute the length secret message. Step 2: Find the edges of stego file by using the Robinson compass filter that is used in hiding process. Step 3: Create array of random numbers that used in hiding process. Step 4: According to the size of secret data , the length of Extracting process will be performed by reading the sequence bytes from stego file and extracting the secret data according to the random positions that are stored in array. Step 5:Save the data of message in a new file.
Extracting Algorithm (2) Input :- Stego file Output:- Secret message Step 1: Read stego file. Step 2: While not end of secret data file Do Step 3: Cut the last bits from each byte of edges of stego data according to the to the random positions that are stored in array and the length of secret message. Step 4: Collection these extracted bits in bytes. Step 5: Convert the secret data bytes into ASCII code. Then convert each ASCII code to characters. Step 6:Display the extracted string as a file. Step 7: End.
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Conclusion In this paper, we have investigated the problem of security in cloud computing, which is essentially a distributed storage system. To ensure the security of user’ data in cloud storage, we proposed an efficient steganography technique for enhancing security on data-at-rest. This technique used edges of color images to hide the secret data. So, when the images are stored in the cloud data Centre, no one can view the secret data without any proper identification. Our scheme almost guarantees the security of data when it is residing on the data center of any Cloud Service Provider (CSP).
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