Biblio

The steady decline of IP transit prices in the past two decades has helped fuel the growth of traffic demands in the Internet ecosystem. Despite the declining unit pricing, bandwidth costs remain significant due to ever-increasing scale and reach of the Internet, combined with the price disparity between the Internet's core hubs versus remote regions. In the meantime, cloud providers have been auctioning underutilized computing resources in their marketplace as spot instances for a much lower price, compared to their on-demand instances. This state of affairs has led the networking community to devote extensive efforts to cloud-assisted networks - the idea of offloading network functionality to cloud platforms, ultimately leading to more flexible and highly composable network service chains.We initiate a critical discussion on the economic and technological aspects of leveraging cloud-assisted networks for Internet-scale interconnections and data transfers. Namely, we investigate the prospect of constructing a large-scale virtualized network provider that does not own any fixed or dedicated resources and runs atop several spot instances. We construct a cloud-assisted overlay as a virtual network provider, by leveraging third-party cloud spot instances. We identify three use case scenarios where such approach will not only be economically and technologically viable but also provide performance benefits compared to current commercial offerings of connectivity and transit providers.

Cloud computing is one of the emerging area in the business world that help to access resources at low expense with high privacy. Security is a standout amongst the most imperative difficulties in cloud network for cloud providers and their customers. In order to ensure security in cloud, we proposed a framework using different encryption algorithm namely Extended hill cipher and homomorphic encryption. Firstly user data/information is isolated into two parts which is static and dynamic data (critical data). Extended hill cipher encryption is applied over more important dynamic part where we are encrypting the string using matrix multiplication. While homomorphic encryption is applied over static data in which it accepts n number of strings as information, encode each string independently and lastly combine all the strings. The test results clearly manifests that the proposed model provides better information security.

Shamir's Secret Sharing Scheme is well established and widely used. It allows a so-called Dealer to split and share a secret k among n Participants such that at least t shares are needed to reconstruct k, where 0 \textbackslashtextbackslashtextless; t ≤ n. Nothing about the secret can be learned from less than t shares. To split secret k, the Dealer generates a polynomial f, whose independent term is k and the coefficients are randomly selected using a uniform distribution. A share is a pair (x, f(x)) where x is also chosen randomly using a uniform distribution. This scheme is useful, for example, to distribute cryptographic keys among different cloud providers and to create multi-factor authentication. The security of Shamir's Secret Sharing Scheme is usually analyzed using a threat model where the Dealer is trusted to split and share secrets as described above. In this paper, we demonstrate that there exists a different threat model where a malicious Dealer can compute shares such that a subset of less than t shares is allowed to reconstruct the secret. We refer to such subsets as hidden sets. We formally define hidden sets and prove lower bounds on the number of possible hidden sets for polynomials of degree t - 1. Yet, we show how to detect hidden sets given a set of n shares and describe how to create hidden sets while sharing a secret using a modification of Shamir's scheme.

To ensure the accountability of a cloud environment, security policies may be provided as a set of properties to be enforced by cloud providers. However, due to the sheer size of clouds, it can be challenging to provide timely responses to all the requests coming from cloud users at runtime. In this paper, we design and implement a middleware, PERMON, as a pluggable interface to OpenStack for intercepting and verifying the legitimacy of user requests at runtime, while leveraging our previous work on proactive security verification to improve the efficiency. We describe detailed implementation of the middleware and demonstrate its usefulness through a use case.

Authorizing access to the public cloud has evolved over the last few years, from simple user authentication and password authentication to two-factor authentication (TOTP), with the addition of an additional field for entering a unique code. Today it is used by almost all major websites such as Facebook, Microsoft, Apple and is a frequently used solution for banking websites. On the other side, the private cloud solutions like OpenStack, CloudStack or Eucalyptus doesn't offer this security improvement. This article is presenting the advantages of this new type of authentication and synthetizes the TOTP authentication forms used by major cloud providers. Furthermore, the article is proposing to solve this challenge by presenting a practical solution for adding two-factor authentication for OpenStack cloud. For this purpose, the web authentication form has been modified and a new authentication module has been developed. The present document covers as well the entire process of adding a TOTP user, generating and sending the secret code in QR form to the user. The study concludes with OpenStack tools used for simplifying the entire process presented above.

An effective storage and management of file systems is very much essential now a days to avoid the wastage of storage space provided by the cloud providers. Data de-duplication technique has been used widely which allows only to store a single copy of a file and thus avoids duplication of file in the cloud storage servers. It helps to reduce the amount of storage space and save bandwidth of cloud service and thus in high cost savings for the cloud service subscribers. Today data that we need to store are in encrypted format to ensure the security. So data encryption by data owners with their own keys makes the de-duplication impossible for the cloud service subscriber as the data encryption with a key converts data into an unidentifiable format called cipher text thus encrypting, even the same data, with different keys may result in different cipher texts. But de-duplication and encryption need to work in hand to hand to ensure secure, authorized and optimized storage. In this paper, we propose a scheme for file-level de-duplication on encrypted files like text, images and even on video files stored in cloud based on the user's privilege set and file privilege set. This paper proposed a de-duplication system which distributes the files across different servers. The system uses an Erasure Correcting Code technique to re-construct the files even if the parts of the files are lost by attacking any server. Thus the proposed system can ensure both the security and reliability of encrypted files.

As cloud computing becomes increasingly pervasive, it is critical for cloud providers to support basic security controls. Although major cloud providers tout such features, relatively little is known in many cases about their design and implementation. In this paper, we describe several security features in OpenStack, a widely-used, open source cloud computing platform. Our contributions to OpenStack range from key management and storage encryption to guaranteeing the integrity of virtual machine (VM) images prior to boot. We describe the design and implementation of these features in detail and provide a security analysis that enumerates the threats that each mitigates. Our performance evaluation shows that these security features have an acceptable cost-in some cases, within the measurement error observed in an operational cloud deployment. Finally, we highlight lessons learned from our real-world development experiences from contributing these features to OpenStack as a way to encourage others to transition their research into practice.

Cloud computing is a remarkable model for permitting on-demand network access to an elastic collection of configurable adaptive resources and features including storage, software, infrastructure, and platform. However, there are major concerns about security-related issues. A very critical security function is user authentication using passwords. Although many flaws have been discovered in password-based authentication, it remains the most convenient approach that people continue to utilize. Several schemes have been proposed to strengthen its effectiveness such as salted hashes, one-time password (OTP), single-sign-on (SSO) and multi-factor authentication (MFA). This study proposes a new authentication mechanism by combining user's password and modified characters of CAPTCHA to generate a passkey. The modification of the CAPTCHA depends on a secret agreed upon between the cloud provider and the user to employ different characters for some characters in the CAPTCHA. This scheme prevents various attacks including short-password attack, dictionary attack, keylogger, phishing, and social engineering. Moreover, it can resolve the issue of password guessing and the use of a single password for different cloud providers.

Numerous cloud service certifications (CSCs) are emerging in practice. However, in their striving to establish the market standard, CSC initiatives proceed independently, resulting in a disparate collection of CSCs that are predominantly proprietary, based on various standards, and differ in terms of scope, audit process, and underlying certification schemes. Although literature suggests that a certification's design influences its effectiveness, research on CSC design is lacking and there are no commonly agreed structural characteristics of CSCs. Informed by data from 13 expert interviews and 7 cloud computing standards, this paper delineates and structures CSC knowledge by developing a taxonomy for criteria to be assessed in a CSC. The taxonomy consists of 6 dimensions with 28 subordinate characteristics and classifies 328 criteria, thereby building foundations for future research to systematically develop and investigate the efficacy of CSC designs as well as providing a knowledge base for certifiers, cloud providers, and users.