Frequently Asked
Questions

Network Technology

What do you mean by Device-to-Device (D2D) Connectivity?
D2D means your phone links and exchanges data with other phones in close proximity, without requiring Internet connectivity, and without spending any of your cellular data or requiring a public WiFi hotspot with Internet connectivity.
How do you achieve seamless D2D Connectivity?
Our solution mixes Bluetooth Low Energy (BLE) and WiFi-Direct technologies, being able to transfer content as fast as 250 Mbps but also being energy efficient and not wasting energy when there are no connectivity opportunities.
Is D2D communication secure and private?
All D2D transfers are encrypted, therefore, no one can eavesdrop on the content being transferred. Users can choose to be anonymous if they so wish when sharing content with others in the vicinity, increasing the privacy of end-users. Finally, no content is uploaded, stored or otherwise tracked in any central server ever. Depending on the use-case, content will also be ephemeral, meaning that it will self-destroy after some pre-determined amount of time.
What data do you collect?
DataHop is a privacy-preserving network. The only statistics that DataHop collects from its users are transfer statistics for the sole purpose of rewarding users for their contribution to the network. However all information is anonymised and users will be able to opt out of these statistics at the expense of not being rewarded for their contribution to the DataHop Network.
What is Content Centric Connectivity?
DataHop makes use of the Content Centric Networking paradigm to develop a new Content Centric Connectivity mechanism. According to this smart connectivity solution, devices connect to each other only when they discover content of interest in the vicinity. In other words, devices connect directly to content, independently of the device where this content is stored.
What is Content or Data Centric Networking?
Content Centric Networking is a new networking paradigm where endpoints in the Internet communicate based on explicitly-named, self-identifiable and signed data, instead of IP addresses. In Content-Centric Networking the main network-layer primitive is a content name, as compared to the host's IP address. That said, in Content-Centric Networking, users are agnostic to which host serves the content and are only interested in the content itself, which can be served by any cache or host.

Blockchain Technology

Which blockchain do you use?
Our layer-2 consensus algorithm, called Proof-of-Prestige and published at IEEE ICBC 2019, can be deployed on top of any Proof-of-Stake blockchain. The main requirement of DataHop is scalability, as DataHop requires large number of transactions. We are currently considering several options with the most prevalent one being Cosmos.
What is Proof-of-Prestige?
While in some cases the proof of some utility or service can be proved, the majority of tasks are impossible to verify. This is also the case with data transfers between user devices in a D2D manner. In order to deal with such cases, we designed "Proof-of-Prestige" (PoP)—a reward system that can run on top of Proof-of-Stake blockchains. PoP introduces "prestige", which can be thought of as a kind of social capital, is a volatile resource and, in contrast to crypto-currency coins, regenerates over time. Prestige can be gained by performing useful work, spent when benefiting from services and directly translates to users minting power. PoP is resistant against Sybil and Collude attacks and can be used to reward workers for completing unverifiable tasks. You can find the related paper that provides all the details here .
What's a simple explanation of progressive mining?
As users distribute content, they naturally build distribution trees. The distribution rewards should therefore, be split between the users. According to our design, users are not only rewarded for their immediate file transfers, but also for the transfers of their descendants in their distribution trees. You can think of it as a recursive incentives scheme, similar to the technique used by the MIT team during the The Red Balloon Challenge. However, our scheme is adapted to work in a digital environment and can protect against both the Sybil Attack and collude attacks. See the paper for more information.
What are the main principles of your Proof-of-X Consensus algorithm?
Our Proof-of-Prestige algorithm is based on Proof-of-Stake, but introduces "prestige" - an additional resource to crypto-coins. Prestige is renewable and directly determines users' probability of minting a new block. Users can increase their amount of prestige by holding more coins (as in traditional Proof-of-Stake systems), but also by performing useful work (transfering files). This is in contrast to alternative PoS systems and incentivises users to contribute to the network.

Security & Privacy

Can DataHop support individual content publishers?
DataHop not only supports individual content publishers, but also allows independent publishers to distribute their content and get rewarded by that without having to lock their content rights into monopolistic silos.
Can malicious users insert content in DataHop, pretending to be legitimate content publishers?
Both individual and commercial content publishers are authenticated when first joining the DataHop network. Any content published subsequently is signed by the private key of the publisher (unless an individual user wishes to stay totally anonymous). Therefore, any content propagated in the DataHop network is verified (towards the signature of its publisher) and malicious users cannot impersonate others.
Can DataHop support subscription-based (i.e., premium) content?
Yes. Content can be encrypted to provide full confidentality and only users subscribed will have access to the content. We will provide tools for content publishers to ensure that only users with valid subscriptions have access to the DRM (Digital Rights Management) controlled content.

End Users

What devices can join the DataHop network?
Any smartphone device that downloads the DataHop app can join the network. We have released the first version of DataHop for Android. The iOS version will be out soon and we are also building a laptop version of DataHop.
How much can I earn?
DataHop users earn money depending on how active they are (i.e., how many transfers they do), but also depending on how many times the content they transferred is disseminated further by other users in their distribution tree. The reward is higher when participating in the dissemination of content that eventually becomes popular. DataHop is creating a digital marketplace for incentivised content propagation at the edge of the network, so the dynamics of contribution to the network and the corresponding reward will be influenced by several factors.
What privacy guarantees does DataHop provide?
DataHop is a distributed virtual storage space among users' mobile devices. Data shared in the DataHop network is never uploaded to any server, hence, no "data lock-in" is present in the DataHop ecosystem. DataHop ensures full privacy of its users providing content encryption and node anonymity in D2D communications.
How much battery does DataHop consume for the average user?
We have run extensive tests with our proof-of-concept prototype on several Android devices and have found that DataHop uses less than 10% of an average smartphone battery for a whole day of contributing to the network.
How much memory does DataHop need from the average user?
It is up to each user to select how much memory to contribute to the DataHop network. The more the memory that one contributes the higher the chances of stored content being of interest to others and therefore, being rewarded for distributing content.