Bridging Networks with Hyperdata

Andrei Sambra

Mar 4, 2019 • 6 min read

We are excited to share with you a new idea that we hope will help bridge existing decentralization efforts. By writing about it, we hope to start a conversation that will enable cooperation among existing projects. To this end we propose Hyperdata, a storage & network-agnostic data model and schema(s) for linking data across different networks and platforms.

We understand that achieving decentralization on the Web today is not easy. Although the Web itself is already decentralized, the services operating on top of it are not. I admit that while it's great to have a lot of teams and projects working on decentralized services, in most cases it works against decentralization in the long term as they introduce more network fragmentation.

Typically what happens is that when Project A releases their software, it is only able to interact with other instances of Project A (e.g. Diaspora, MaidSafe, Matrix, etc.). Blockchain projects are also in a similar situation, while still operating at the same application layer as the Web -- developers can build applications that utilize the underlying network (e.g. uPort, Blockstack). However, the biggest difference between the Web and blockchain networks is that the Web is driven by a common set of standards as well as a non-profit standards body, whereas blockchain projects are very fragmented and each come out with their own standards and self-governance. This translates into a higher risk of seeing the network collapse due to financial reasons, bad management, or simply because the project has become obsolete.

Being realistic, we should face the fact that pretty much no project is guaranteed to last forever. Therefore if we plan to build something that lasts, we need to look at the big picture and find solutions that should not depend on any one network in particular. To be more precise, we should aim to develop a storage-agnostic data model and schema(s) for linking data across different domains and platforms. For example, this means that a piece of data hosted on the Web could link to another one hosted on the InterPlanetary File System (IPFS), which in turn could potentially link to data hosted even on your local file system.

Why hyperdata?

An immediate advantage of being storage/network-agnostic is that developers can build software that transcends specific network constraints, while still taking advantage of everything each network has to offer. For example, by default IPFS does not offer any support for identity and authorship. Hyperdata would allow payloads to be signed, making sure that authors will always have a way to prove who created the content. At the same time, the signatures (i.e. cryptographic proofs) can also be computed independently from the network and in some cases even the identity provider (more in the example below). In fact, proving a signature may not even require network access at all, if the device has been provisioned with the right keys (similar to PGP).

Identity is in most cases tightly coupled with the application and always coupled with the network. Today uPort and Blockstack claim to offer decentralized identity that can be reused in apps running on their networks. While this is definitely a step forward, it would be great to find a solution that goes beyond any given network. Hyperdata does not mandate nor does it even offer an identity solution. It encourages however the use of Decentralized Identifiers (DIDs). We feel that DIDs fit very well with hyperdata, since it allows arbitrary parties to resolve DIDs to an endpoint and keys, even if they are not on the same network.

Last but not least is data portability, especially in light of EU's new General Data Protection Regulation (GDPR). Data can be stored anywhere, since it is no longer tightly coupled with the network. It can also be stored on multiple networks at the same time, to offer increased redundancy.

How does hyperdata work?

The concept itself is very straightforward. We have a payload and a signature over the whole payload. Please remember this is still very early stuff and will definitely evolve in time.

The payload contains the metadata as well as the actual content.

type field [optional] - can be added by applications that generate the content.
reference field - either a URI or another nested piece of hyperdata
created field - a timestamp when the content was created
author field - preferably a DID
body field - the actual content

Javascript { "type": "AKASHAComment", "ref": "https://twitter.com/AkashaProject/status/1085598391827120130", "created": "2019-01-14T05:34:22Z", "author": "did:muport:QmYiEMtYauiPrak1uPN8UV82wztgF9cgL4gkCMtDUxUbao", "body": "Awesome post by AKASHA." }

In the example above, user identities are expressed using DIDs, in this case a 3Box identity.

The signature is computed over a binary serialization of the payload, and it contains all the necessary information to allow proof computation. The fields are based on the Security Vocabulary schema.

Javascript { "type": "Web3Signature", "creator": "did:muport:QmYiEMtYauiPrak1uPN8UV82wztgF9cgL4gkCMtDUxUbao", "digestAlgorithm": "https://www.ietf.org/assignments/jwa-parameters#SHA256", "signatureValue": "0x1ba149b9...e461c" }

To perform the signature step above, we've used our Ethereum keys (through MetaMask) to create a 3Box DID and corresponding profile page, without exposing our private key at any point during the process. Next, we used the web3 library (through MetaMask) to personally sign the payload. Here is how the whole document looks once we've added the corresponding context links.

Javascript { "@context": [ "https://w3id.org/identity/v1", "https://akasha.org/contexts/comments.jsonld" ], "payload": { "type": "AKASHAComment", "ref": "https://twitter.com/AkashaProject/status/1085598391827120130", "created": "2019-01-14T05:34:22Z", "author": "did:muport:QmYiEMtYauiPrak1uPN8UV82wztgF9cgL4gkCMtDUxUbao", "body": "Awesome post by AKASHA." }, "signature": { "type": "Web3Signature", "creator": "did:muport:QmYiEMtYauiPrak1uPN8UV82wztgF9cgL4gkCMtDUxUbao", "digestAlgorithm": "https://www.ietf.org/assignments/jwa-parameters#SHA256", "signatureValue": "0x1ba149b9...e461c" } }

Let's look at an example!

Let’s consider the following use case of an application (we may call it comments.com) through which a group of people start a conversation based on any link (in this case a Tweet). Additionally, comments can be stored on IPFS to make them decentralized but also resistant to censorship. We can see already that our application will have to be able to resolve links coming from the Web (Twitter in this example) but also from IPFS. Perhaps we might also want to store drafts locally or integrate Slack?

Starting a discussion

First we need to model the initial comment containing the Tweet link. The author is someone having a decentralized identity provider (using 3Box) that has created the following user identifier -- did:muport:QmYiEMtYauiPrak1uPN8UV82wztgF9cgL4gkCMtDUxUbao.

Let's see how this bit of hyperdata would look, using a signed JSON-LD representation.

You might have noticed that in the @context property, we have added a placeholder for "https://akasha.org/contexts/comments.jsonld". This particular context document will contain the missing property definitions that are relevant for our application -- such as comment, ref, author, body, and scope.

Finally, because the JSON-LD document is fully self-describing and it contains a signature that doesn't mandate where the data should be stored, we can safely add it to IPFS resulting then in the following CID QmUEpVDGumYocPtX9iqSMf1Czpf7qHN9W8Xe5KjaDstRPn.

Adding replies to comments

Replies are almost identical to comments, with the exception that they are of a different type and they refer to another comment instead of the post. Let's take a look!

Javascript { "@context": [ "https://w3id.org/identity/v1", "https://akasha.org/contexts/comments.jsonld" ], "payload": { "type": "AKASHAReply", "ref": "ipfs://QmUEpVDGumYocPtX9iqSMf1Czpf7qHN9W8Xe5KjaDstRPn", "created": "2019-01-15T09:21:44Z", "author": "did:sov:WRfXPg8dantKVubE3HX8pw", "body": "Thanks for sharing, I also love AKASHA." }, "signature": { "type": "RsaSignature2018", "creator": "did:sov:WRfXPg8dantKVubE3HX8pw/keys/1", "digestAlgorithm": "https://www.ietf.org/assignments/jwa-parameters#SHA256", "signatureValue": "9feAlB0L2..Z2JF29=" } }

Adding comments that are not on IPFS

We can also add comments that can be hosted on the Web. What matters in the end is just the content itself, the raw data.

Javascript { "@context": [ "https://w3id.org/identity/v1", "https://akasha.org/contexts/comments.jsonld" ], "payload": { "type": "AKASHAComment", "ref": "ipfs://QmUEpVDGumYocPtX9iqSMf1Czpf7qHN9W8Xe5KjaDstRPn", "created": "2019-01-15T12:11:54Z", "author": "did:uport:1690e4b1adb3GYTBaaKAgr76uY7iSe1Uf28", "body": "Cool stuff, I'm going to follow @AKASHA now." }, "signature": { "type": "RsaSignature2018", "creator": "did:uport:1690e4b1adb3GYTBaaKAgr76uY7iSe1Uf28/keys/6", "digestAlgorithm": "https://www.ietf.org/assignments/jwa-parameters#SHA256", "signatureValue": "BavEll0/I1..W3JT24=" } }

This comment can be published on Web 2.0 servers (in this case on Github pages), since we know it will be served with the right content type -- for example https://deiu.github.io/cdn/comment-ab019f3.jsonld.

Displaying comments in the app

Now the "magic" happens. As per above, the app at comments.com maintains an index of comments for a given resource (i.e. the initial tweet). In order for the app to display the comments it needs to fetch all of them before anything else happens. To do so, it looks at the index to find a corresponding protocol handler/fetcher for each comment (ipfs:// or https:// in this case). Dereferencing the URI of each comment from the index results in a document containing machine-readable information expressed as JSON-LD. All comments then could be ordered based on the time when they were created.

Also, Comments.com has been used here as an example application of hyperdata. We haven’t attempted to address the question of comment moderation, decoupled as it is from the hyperdata model, but rest assured we appreciate the balance between censorship and allowing a community to keep things civilized.

Things to consider

One issue that is easy to spot right away is that we cannot discover and list all comments for a post unless we aggregate everything ourselves, independently from the main post. This means the application provider (i.e. comments.com) has to maintain an index of all the comments in a transparent way that can be reproduced by others in order to avoid censorship issues. We are still investigating different solutions to help us with data discovery in a decentralized way.