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Current methods to store and transfer medical neuroimaging data raise issues with security and transparency, and novel protocols are needed. Ethereum smart contracts present an encouraging new option. Ethereum is an open-source platform that allows users to construct smart contracts—self-executable packages of code that exist in the Ethereum state and allow transactions under programmed conditions. The present study developed a proof-of-concept smart contract that stores patient brain tumor data such as patient identifier, disease, grade, chemotherapy drugs, and Karnofsky score. The InterPlanetary file system was used to efficiently store the image files, and the corresponding content identifier hashes were stored within the smart contracts. Testing with a private, proof-of-authority network required only 889 MB of memory per insertion to insert 350 patient records, while retrieval required 910 MB. Inserting 350 patient records required 907 ms. The concept presented in this study exemplifies the use of smart contracts and off chain data storage for efficient retrieval/insertion of medical neuroimaging data.

Healthcare, one of the most important industries, is data-oriented, but most of the research in this industry focuses on incorporating the internet of things (IoT) or connecting medical equipment. Very few researchers are looking at the data generated in the healthcare industry. Data are very important tools in this competitive world, as they can be integrated with artificial intelligence (AI) to promote sustainability. Healthcare data include the health records of patients, drug-related data, clinical trials data, data from various medical equipment, etc. Most of the data management processes are manual, time-consuming, and error-prone. Even then, different healthcare industries do not trust each other to share and collaborate on data. Distributed ledger technology is being used for innovations in different sectors including healthcare. This technology can be incorporated to maintain and exchange data between different healthcare organizations, such as hospitals, insurance companies, laboratories, pharmacies, etc. Various attributes of this technology, such as its immutability, transparency, provenance etc., can bring trust and security to the domain of the healthcare sector. In this paper, a decentralized access control model is proposed to enable the secure interoperability of different healthcare organizations. This model uses the Ethereum blockchain for its implementation. This model interfaces patients, doctors, chemists, and insurance companies, empowering the consistent and secure exchange of data. The major concerns are maintaining a history of the transactions and avoiding unauthorized updates in health records. Any transaction that changes the state of the data is reflected in the distributed ledger and can be easily traced with this model. Only authorized entities can access their respective data. Even the administrator will not be able to modify any medical records.

In this paper, we focus on Information-Centric Delay-Tolerant Network (ICDTN), which incorporates the communication paradigm of Information-Centric Networking (ICN) into Delay-Tolerant Networking (DTN). Conventional ICNs adopt a naming scheme that names the content with the content identifier. However, a past study proposed an alternative naming scheme that describes the name of content with the content descriptor. We believe that, in ICDTN, it is more suitable to utilize the approach using the content descriptor. In this paper, we therefore propose keyword-based ICDTN that resolves content requests and deliveries contents based on keywords, i.e., content descriptor, in the request and response messages.

Wenn man an die heutige Speichermenge, die benötigte Dateipersistenz, die hohe Verfügbarkeit und die größeren Dateigrößen denkt, war ein Speichersystem immer der zentrale Fehler, aber auch ein notwendiger Faktor für die meisten aktuellen End- und/oder Power-User. In Anbetracht des ungenutzten Speicherplatzes auf den Clients/Arbeitsplätzen der Endanwender, vor allem in großen Unternehmen, gibt es einigen oder im besten Fall sehr viel freien Speicherplatz, der für einen anderen Zweck wie eine kombinierte Dateiablage genutzt werden könnte. Ein Ort, an dem Daten sicher, ausfallsicher, redundant und immer zugänglich gespeichert werden können. Unter diesem Gesichtspunkt ist IPFS (InterPlanetary File System), ein Peer-to-Peer-Hypermedia-Protokoll, das eine sichere inhaltsbasierte Adressierung und Funktionalität zur Speicherung und Verteilung von Daten in einem dezentralen verteilten Datensystem bietet, sehr gut geeignet, um oben genannte Speicherplätze zu kombinieren. Außerdem spart IPFS durch seine Deduplizierung von Dateien Bandbreite und wird in dieser Arbeit als grundlegendes Dateisystem für eine dezentrale Speichersystemlösung für Mehrbenutzerzwecke verwendet. Darüber hinaus bietet IPFS auch eine Versionskontrolle für Dateien. Doch die genannten Vorteile der Deduplizierung gehen leider mit einigen Nachteilen einher, wenn man IPFS in einem Mehrbenutzersystem einsetzt. Diese Arbeit konzentriert sich speziell auf die Probleme, die in einem deduplizierten Dateisystem auftreten, das für den Mehrbenutzerbetrieb und die Dateispeicherung verwendet wird. IPFS behält die Anzahl der Dateien nicht im Auge und speichert Dateien nur einmal, wenn sie den Deduplizierungsregeln entsprechen. Dies ist ein Problem, wenn dieselbe Datei von zwei einzelnen Benutzern auf demselben System gespeichert wird. Daher wird in diesem Beitrag eine Lösung für das genannte Problem vorgestellt, indem eine zusätzliche Logikschicht eingeführt wird, die die gespeicherten Dateien, ihre Anzahl und die Benutzerrechte für die gespeicherten Dateien in einem privaten dezentralen Dateispeichersystem verfolgt. Diese Schicht wird durch eine Kombination von zusätzlichen Suiten und Protokollen realisiert. Dazu gehören IPFS als Dateisystem, IPFS-Cluster für die Verteilung und Propagierung von Inhalten im System und MongoDB als Datenbank, um Dateiberechtigungen und Dateizahlen auf gespeicherte Dateien abzubilden. Es bildet IPFS-Hashes von gespeicherten Dateien in der Datenbank ab, mit zusätzlichen Berechtigungen und Dateizahlen dieser. Die Ergebnisse dieses Papiers liefern zusätzliches Diskussionsmaterial über Verbesserungen des genannten Systems, indem die eingeführte Schicht zu einer vollständig dezentralen Lösung geändert wird, indem Berechtigungsinformationen von Dateien in einer Blockchain gespeichert werden. Thinking about today’s file sizes storage amount, needed file persistence, high availability and bigger file sizes, a storage system was always the central failure but also a needed factor for most of current end and/or power users. Considering the unused storage space on end user clients/workstations especially in big companies, there is some or in the best-case plenty free space that could be allocated and used for some other purpose like a combined file storage. A place where data can be stored securely, fail safe, redundant and always accessible. This taken into account IPFS (InterPlanetary File System), a peer-to-peer hypermedia protocol that offers secure content based addressing and functionality for saving and distributing data in a decentralized distributed data-system is very well suited for combining above mentioned storage spaces. Furthermore IPFS saves bandwidth through it's deduplication of files and is used in this paper as fundamental filesystem for a decentralized storage system solution for multi-user purposes. In addition IPFS also provides version control for files. But mentioned advantages of deduplication unfortunately come with some disadvantages when using IPFS in a multi-user system. This work focuses especially on the problem that arise in a deduplicated filesystem that is used for multi-user operation and file storage. IPFS does not keep track of file counts and stores files just once if they fit the deduplication rules. This is a problem when the same file is stored by two individual users on sad system. Therefore this paper presents a solution for mentioned problem by introducing an additional logic layer that keeps track of saved file, their count and user permissions on those saved in a private decentralized file storage system. This layer is realized through a combination of additional suites and protocols. That include IPFS as filesystem, IPFS cluster for the distribution and propagation of content across the system and mongoDB as database to map file permissions and file counts to saved files. It maps IPFS hashes of saved files into the database with additional permission and file counts of those. Findings of this paper provide additional discussion material about improvements of mentioned system by changing the introduced layer to a completely decentralized solution by saving permission informations of files to a blockchain.

Mit dem Aufkommen von Blockchain- und Smart Contracts ist eine steigende Komplexität der Transaktionen im Distributed Ledger ersichtlich. Dieses Problem führte dazu, die bei Transaktionen erzeugten Daten an einen Dienst auszulagern, der den hohen Speicherbedarf besser bewältigen kann. Diese Speicherlösung ist vorzugsweise als dezentraler Dienst wie IPFS organisiert. Der Gedanke, Transaktionsdaten auszulagern, ist zwar ein Schritt in die richtige Richtung, lässt aber einige Fragen offen. Zum einen ist die Frage, wem die Verantwortung für die Speicherung der Transaktionsdaten übertragen werden soll, nicht trivial. Ein weiteres Problem betrifft die Fehlertoleranz, insbesondere im Hinblick auf die Verfügbarkeit der ausgelagerten Transaktionsdaten und die Verhinderung oder Erkennung von Manipulationen oder Datenverlusten. Diese Probleme, insbesondere das Letztere, werden in dieser Arbeit als Hauptdiskussionspunkte dienen. Lösungsansätze umfassen Proof of Storage (PoS), eine Form von Interactive Proof-Systemen, deren Einsatz speziell für die beweisbare Dateiablage vorgesehen ist. Solche Verfahren setzen die Existenz eines Verifizierers voraus, der das Auslagern einer Datei und das Ausstellen von Herausforderungen initiiert. Auf der Empfängerseite eines solchen Protokolls befindet sich ein Prüfer, der die Verfügbarkeit und Integrität der ausgelagerten Daten durch einen vom Protokoll vorgegebenen Herausforderungsmechanismus beweist. Diese Arbeit schlägt ein Schema vor, das für solche Probleme anfällig ist, und zielt darauf ab, die Verwendung von Proof of Storage zu motivieren. Es wird argumentiert, dass die Anfälligkeit für Proof of Storage durch eine lose Kopplung der Technologien von IPFS und Blockchain und das Fehlen von Mechanismen, wie z. B. Challenge/Response-Protokollen zur effizienten Bereitstellung von Proofs of Storage besteht. Darüber hinaus stellen wir unser Schema als ein potenzielles dezentrales Speichernetzwerk auf IPFS und Blockchain vor, das einen umfassenden Satz von Operationen wie das Hinzufügen, Löschen und Abrufen von Dateien erfordert. Erstes erfordert mehrere Schritte, um wirksam zu werden. Es beginnt mit einer Ankündigung eines Clients eine Datei auszulagern, gefolgt von einer Anfrage zur Speicherung durch einen Provider und deren entsprechender Annahme durch einen Client. Dieser Vorgang wird mit einem Acknowledgment abgeschlossen, die die erfolgreiche Auslagerung der Datei eines Kunden darstellt. Das Abrufen von Dateien erfordert die Abfrage des Distributed Ledgers nach dem Content Identifier des IPFS-Objekts. With the advent of blockchain and smart contract based applications comes a steady increase in the complexity of transactions made to the distributed ledger. This problem has led many solutions to outsource the relevant data produced in transactions into a service more capable of handling the high storage demand. This storage solution is preferably organized as a decentralized service like IPFS. While the notion of outsourcing transaction data is a step in the right direction, it leaves some issues unresolved. For one, the question of whom to assign the responsibility for storing the transaction data is a non-trivial one. Another issue is related to Fault Tolerance, especially when considering the availability of the outsourced transaction data and prevention or detection of tampering or loss of data. These problems, especially the latter one, will serve as the major discussion points in this work. Solutions involve proof of storage (PoS), which are a form of interactive proof-systems, whose use is specifically intended for provable file storage. Such schemes assume the existence of a verifier initiating the outsourcing of a file and the issuing of challenges. On the receiving side of such a protocol is a prover, proving the availability and integrity of the outsourced data through a challenge mechanism dictated by the protocol. This work proposes a scheme that is susceptible to such issues and aims to motivate the utilization of proof of storage. Susceptibility to proof of storage is argued to exist through a loose coupling of the technologies of IPFS and blockchain and the lack of mechanisms, such as a challenge/response protocol, to efficiently provide Proofs of Storage. Furthermore, we introduce our scheme as a potential decentralized storage network on IPFS and blockchain requiring a comprehensive set of operations, such as the adding, deletion, and retrieval of files. The first one, representing multiple steps to take effect. First, starting with an announcement and indication of a client’s will to outsource a file, following with a request for storage by a provider and its corresponding acceptance by a client. This procedure is finished with an acknowledgment, indicating successful outsourcing of a client’s file. Retrieval of files requires querying the distributed ledger for the content address of the IPFS Object.

Current IP based network does not always efficiently deliver contents over IP based network even though large size contents greatly increase traffic volume of network. Content Centric Network (CCN) has been proposed as new network architecture to solve this problem. CCN directly use a content identifier to obtain content without a content location in the network. Then, the user has to get a content identifier before requesting the content but a way to get content information including a content identifier has not been well studied in CCN architecture. To solve this problem, we propose a content registration method for CCN routers with a blockchain technology to get content information in the architecture. We design and implement the content registration in CCN software platform Cefore and evaluated content information registration time.

In Named Data Networking (NDN), a client requests a content object by its content identifier, instead of the server's IP address. When a router or a node around the client stores the content in the cache, it transfers the content from the cache. As a result, it is possible to provide information quickly and efficiently to many users. In NDN, a content distributor can configure the content's expiration time at each cache. The expiration time should be long enough to use the cache effectively and decrease the amount of traffic. However, if the expiration time is too long this increases the possibility of receiving old content. A shorter expiration time reduces this possibility but this causes the amount of traffic to increase instead. In order to solve this trade-off relationship, we proposed an automatic cache update method where each router queries the version number of all content in the cache to automatically remove old content. Since it is too difficult to set an appropriate inquiry interval for all the content, we also proposed a cache update method based on content update dynamic queries to dynamically change the inquiry interval when each content object is not updated. This paper improves this method by introducing a cooperative update mechanism to reduce the amount of traffic in the network and the number of times old content is received. It also evaluates the method on the generated topology that is similar to real topology and shows that, for example, when the cache size on all routers is large enough, although the difference in the average aggregated traffic is larger than that of the author's first method where the inquiry interval was 270 seconds by 49.1–84.9 GBytes for the experimental period (7 days) (= 4.9–8.4 MBytes per minute), the number of inquiries all routers generated is reduced by 131232.6– 1159687.9 times over 7 days (= 13.0–115.0 times per minute).

In this work, we explore a prediction method, based on the Kalman filter, for multimedia content delivery purposes. In summary, we predict the multimedia content based on their respective multimedia content identifier, such as by means unique identifiers in the network layer (using the DSCP field in an IP network, for example) or in the application layer (using application content tags, for example). A computational environment, simulating four multimedia services, is used to obtain experimental results. The obtained results show that the proposed method can be used to perform the multimedia content prediction based on their multimedia content identifiers. This approach is important to improve the multimedia content delivery and to increase the user-perceived Quality of Experience (QoE).