Treasure Island Security framework : A Generic Security Framework for public clouds

In this thesis we introduce a generic security framework for public clouds called Treasure Island Security framework that is designed to address the issues related to cloud computing security and specifically key-management in untrusted domains. Nowadays many cloud structure and services are provided but as an inevitable concomitant to these new products, security issues increase rapidly. Availability, integrity of data, lack of trust, confidentiality as well as security issues are also of great importance to cloud computing users; they may be more skeptical of the cloud services when they feel that they might lose the control over their data or the structures that the cloud provided for them.   Because of deferred control of data from customers to cloud providers and unknown number of third parties in between, it is almost impossible to apply traditional security methods. We present our security framework, with distributed key and sequential addressing in a simple abstract mode with a master server and adequate number of chunk servers. We assume a fixed chunk size model for large files and sequentially distribution file system with 4 separated key to decrypt/encrypt file. After reviewing the process, we analyze the Distributed Key and Sequentially Addressing Distributed file system and it's Security Risk Model. The focus of this thesis is on increasing security in untrusted domain especially in the cloud key management in public cloud. We discuss cryptographic approaches in key-management and suggest a novel cryptographic method for public cloud's key-management system based on forward-secure public key encryption, which supports a non-interactive publicly verifiable secret sharing scheme through a tree access structure. We believe that Treasure Island Security Framework can provide an increased secure environment in untrusted domains, like public cloud, in which users can securely reconstruct their secret-keys (e.g. lost passphrases). Finally, we discuss the advantages and benefits of Cloud Computing Security Framework with Distributed Key and Sequentially Addressing Distributed file system and cryptographic approaches and how it helps to improve the security levels in cloud systems.  M.S

CageCoach: Sharing-Oriented Redaction-Capable Distributed Cryptographic File System

The modern data economy is built on sharing data. However, sharing data can be an expensive and risky endeavour. Existing sharing systems like Distributed File Systems provide full read, write, and execute Role-based Access Control (RBAC) for sharing data, but can be expensive and difficult to scale. Likewise such systems operate on a binary access model for their data, either a user can read all the data or read none of the data. This approach is not necessary for a more read-only oriented data landscape, and one where data contains many dimensions that represent a risk if overshared. In order to encourage users to share data and smooth out the process of accessing such data a new approach is needed. This new approach must simplify the RBAC of older DFS approaches to something more read-only and something that integrates redaction for user protections. To accomplish this we present CageCoach, a simple sharing-oriented Distributed Cryptographic File System (DCFS). CageCoach leverages the simplicity and speed of basic HTTP, linked data concepts, and automatic redaction systems to facilitate safe and easy sharing of user data. The implementation of CageCoach is available at https://github.umn.edu/CARPE415/CageCoach

Towards Practical Access Control and Usage Control on the Cloud using Trusted Hardware

Cloud-based platforms have become the principle way to store, share, and synchronize files online. For individuals and organizations alike, cloud storage not only provides resource scalability and on-demand access at a low cost, but also eliminates the necessity of provisioning and maintaining complex hardware installations. Unfortunately, because cloud-based platforms are frequent victims of data breaches and unauthorized disclosures, data protection obliges both access control and usage control to manage user authorization and regulate future data use. Encryption can ensure data security against unauthorized parties, but complicates file sharing which now requires distributing keys to authorized users, and a mechanism that prevents revoked users from accessing or modifying sensitive content. Further, as user data is stored and processed on remote ma- chines, usage control in a distributed setting requires incorporating the local environmental context at policy evaluation, as well as tamper-proof and non-bypassable enforcement. Existing cryptographic solutions either require server-side coordination, offer limited flexibility in data sharing, or incur significant re-encryption overheads on user revocation. This combination of issues are ill-suited within large-scale distributed environments where there are a large number of users, dynamic changes in user membership and access privileges, and resources are shared across organizational domains. Thus, developing a robust security and privacy solution for the cloud requires: fine-grained access control to associate the largest set of users and resources with variable granularity, scalable administration costs when managing policies and access rights, and cross-domain policy enforcement. To address the above challenges, this dissertation proposes a practical security solution that relies solely on commodity trusted hardware to ensure confidentiality and integrity throughout the data lifecycle. The aim is to maintain complete user ownership against external hackers and malicious service providers, without losing the scalability or availability benefits of cloud storage. Furthermore, we develop a principled approach that is: (i) portable across storage platforms without requiring any server-side support or modifications, (ii) flexible in allowing users to selectively share their data using fine-grained access control, and (iii) performant by imposing modest overheads on standard user workloads. Essentially, our system must be client-side, provide end-to-end data protection and secure sharing, without significant degradation in performance or user experience. We introduce NeXUS, a privacy-preserving filesystem that enables cryptographic protection and secure file sharing on existing network-based storage services. NeXUS protects the confidentiality and integrity of file content, as well as file and directory names, while mitigating against rollback attacks of the filesystem hierarchy. We also introduce Joplin, a secure access control and usage control system that provides practical attribute-based sharing with decentralized policy administration, including efficient revocation, multi-domain policies, secure user delegation, and mandatory audit logging. Both systems leverage trusted hardware to prevent the leakage of sensitive material such as encryption keys and access control policies; they are completely client-side, easy to install and use, and can be readily deployed across remote storage platforms without requiring any server-side changes or trusted intermediary. We developed prototypes for NeXUS and Joplin, and evaluated their respective overheads in isolation and within a real-world environment. Results show that both prototypes introduce modest overheads on interactive workloads, and achieve portability across storage platforms, including Dropbox and AFS. Together, NeXUS and Joplin demonstrate that a client-side solution employing trusted hardware such as Intel SGX can effectively protect remotely stored data on existing file sharing services

A comprehensive meta-analysis of cryptographic security mechanisms for cloud computing

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The concept of cloud computing offers measurable computational or information resources as a service over the Internet. The major motivation behind the cloud setup is economic benefits, because it assures the reduction in expenditure for operational and infrastructural purposes. To transform it into a reality there are some impediments and hurdles which are required to be tackled, most profound of which are security, privacy and reliability issues. As the user data is revealed to the cloud, it departs the protection-sphere of the data owner. However, this brings partly new security and privacy concerns. This work focuses on these issues related to various cloud services and deployment models by spotlighting their major challenges. While the classical cryptography is an ancient discipline, modern cryptography, which has been mostly developed in the last few decades, is the subject of study which needs to be implemented so as to ensure strong security and privacy mechanisms in today’s real-world scenarios. The technological solutions, short and long term research goals of the cloud security will be described and addressed using various classical cryptographic mechanisms as well as modern ones. This work explores the new directions in cloud computing security, while highlighting the correct selection of these fundamental technologies from cryptographic point of view