A Fully decentralized framework for securely sharing digital content

Download

index.pdf

Date

2019

Author

Demir, Ahmet Serhat

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

284
views

146
downloads

Blockchain is a secure, immutable, and distributed public ledger that stores transactional data. It enables information transfer without the need for a trusted third party via its decentralized consensus mechanism. Besides finance, blockchain technology has the potential to change several industries, through smart contracts and decentralized applications. This thesis explores using blockchain technology, smart contracts, and Ethereum Web 3.0 stack for secure information and file sharing on a fully decentralized architecture. We aim to remove the need for a central authority in all layers of the application, and thus provide an alternative to the drawbacks of centralized content exchange platforms. Accordingly, a proof-of-concept decentralized application is designed. This design is implemented in the Ethereum ecosystem using blockchain for the immutable distributed ledger, Ether for cash transfers, and smart contracts for application logic. Since data storage in blockchain is expensive, Swarm is used as a decentralized reliable content storage system. Nevertheless, permissionless systems in the Ethereum ecosystem lack necessary data privacy, which causes risk for secure information exchange. In order to provide access control for sensitive content delivery without the need for a pre-shared secret, public key encryption is used. Also, to enable fair exchange between separate untrusted rational parties, a double escrow functionality is implemented as a model of fairness via incentive with deposit penalties. According to the validation and evaluation of our proof-of-concept, we show that Ethereum Web 3.0 stack is applicable to securely sharing and exchanging digital content without relying on a trusted third party.

Subject Keywords

Blockchains (Databases)., Blockchain, smart contract, decentralized application, digital content sharing, fair exchange.

URI

http://etd.lib.metu.edu.tr/upload/12624332/index.pdf
https://hdl.handle.net/11511/44912

Collections

Graduate School of Informatics, Thesis

Suggestions

OpenMETU
Core

Decentralized secure multiparty computation Taşcı, Buse; Cenk, Murat; Department of Cryptography (2019) Advances in blockchain technology have led to new applications that aim to eliminate central systems, to improve transparency and user control in transactions whiledealing with the privacy and security challenges. In this thesis, a system which enables users to control their private data and to share chosen data to other parties usingsecure computation techniques is reviewed. Then, we present a blockchain-based digital identity system depending on this architecture. This system ensures that identity informa...
A new hybrid multi-relational data mining technique Toprak, Seda Dağlar; Toroslu, İ. Hakkı; Department of Computer Engineering (2005) Multi-relational learning has become popular due to the limitations of propositional problem definition in structured domains and the tendency of storing data in relational databases. As patterns involve multiple relations, the search space of possible hypotheses becomes intractably complex. Many relational knowledge discovery systems have been developed employing various search strategies, search heuristics and pattern language limitations in order to cope with the complexity of hypothesis space. In this w...
AN OPTIMISTIC LOCKING TECHNIQUE FOR CONCURRENCY-CONTROL IN DISTRIBUTED DATABASES Halıcı, Uğur (1991-07-01) An optimistic scheme, called ODL, which uses dummy locks to test the validity of a transaction for concurrency control in distributed database systems, is suggested. The dummy locks are long-term locks; however, they do not conflict with any other lock. By the use of long-term dummy locks, the need for the information about the write sets of validated transactions is eliminated and during the validation test only the related sites are checked. Also, the transactions to be aborted are immediately recogniz...
A new design of privilege management infrastructure with binding signature semantics Bıçakçı, Kemal; Baykal, Nazife (2004-01-01) Just like PKI, used to support public key certificates, Privilege Management Infrastructure (PMI) is built to provide a foundation to employ attribute certificates. Although most of the PKI ideas can be applied to PMI as well, PMI has some unique characteristics for instance it should handle attributes containing confidential information. Motivating by this fact, Dawson et al. recently proposed a new PMI design for those who would like to use the outsourced PKI but keep the PMI management inside the organiz...
A high-speed asic implementation of the RSA cryptosystem Yeşil, Soner; Aşkar, Murat; Department of Electrical and Electronics Engineering (2003) This thesis presents the ASIC implementation of the RSA algorithm, which is one of the most widely used Public Key Cryptosystems (PKC) in the world. In RSA Cryptosystem, modular exponentiation of large integers is used for both encryption and decryption processes. The security of the RSA increases as the number of the bits increase. However, as the numbers become larger (1024-bit or higher) the challenge is to provide architectures, which can be implemented in hardware, operate at high clock speeds, use a m...

Citation Formats

A. S. Demir, “A Fully decentralized framework for securely sharing digital content,” Thesis (M.S.) -- Graduate School of Informatics. Cyber Security., Middle East Technical University, 2019.