Self-Sovereign Identity Wallets: A Deep Dive

Understanding SSI Wallets

At their core, SSI wallets are managers of private keys. In the context of cryptocurrency, this function is straightforward. The wallet manages the private keys, storing all the information on the blockchain. However, when it comes to SSI, the situation becomes more complex.

In SSI, you have physical assets like verifiable credentials (VCs), which are typically in the form of JSON-LD or other formats like CBOR. These assets need to be managed and correlated with the Decentralized Identifiers (DIDs), which are the users' digital identities.

The Challenge of Correlation

One of an SSI wallet's most crucial and often misunderstood functions is the correlation between public keys, private keys, and DIDs. When you want to sign a credential, you must effectively manage the relationship between these elements.

For instance, if your private key disappears, you need to manage not just your DID document but also the DID documents of all your relations. This opens up a vast and fascinating world of trust registries, address books, and concepts. The primary function of the identity wallet is to manage your identity’s relations to other people.

Channels and Connections

In the SSI world, channels can be a significant aspect. They are not an open standard but offer something on the representation layer. For example, KERI (Key Event Receipt Infrastructure) provides key event logs and other features.

Connections in an SSI wallet depend on the environment. If you’re working in an environment with git-com, you already have the connections. However, it’s essential to understand that a wallet is a passive entity that manages your keys.

If you want to take part in active interactions like credential exchange, you need to be online and reachable. This is where an agent comes in. An agent is like a wallet on steroids. It has access to your assets and keys and can operate online on your behalf.

Persistence of Credentials

After all the DID management, you need persistence for your credentials. This might seem obvious, but it’s a critical aspect of SSI wallets.

The Role of Revocation Lists

In the SSI landscape, entities are not uncommon to act as issuers, verifiers, and holders. This means that you’re not just owning credentials but also issuing them to others. In such cases, if you want to issue revocable credentials, you must store and publicly publish your revocation lists.

To make your revocation lists public, you’ll need a wallet, an agent, and a mechanism to make these lists accessible. You have a couple of options here. You could host your agent that will own the revocation lists and make them available. Alternatively, you could create an SSI Hub, which has authorization functions, can work with multi-tenancy, and host multiple revocation lists for different users and DIDs.

SSI Wallets: More Than Just Wallets

As you can see, an SSI wallet is rarely just a wallet. It’s often a combination of a wallet, several agents, relays that build the network, and SSI hubs that can store many credentials. These hubs can be larger than your phone or app,

serving multiple users. However, every hub can be turned into an agent if a single user uses it.

Another interesting topic in the SSI world is messaging. Some messaging comes with DIDs, requiring you to persist the messages and organize the threads. However, that’s a topic for another discussion.

Building an SSI Ecosystem

If you decide to build an SSI ecosystem, you’ll need to create a network of wallets and integrate these wallets into the enterprise world. You’ll always face the challenge of solving the SSI wallet problem.

While some ecosystems have partially solved this, there’s still no perfect solution. The quest for the perfect wallet continues, and it might just be that you’ll have to build your own.

This article provides an overview of the entities that exist in the SSI landscape and must be covered by a combination of wallets, agents, and hubs. It’s a complex and evolving field, but it’s possible to navigate it effectively with the right tools and understanding.

The world of SSI is still in its early stages, and there’s plenty of room for innovation and improvement. Whether you’re a developer looking to build your own SSI wallet or an enterprise looking to integrate SSI into your operations, the opportunities are vast and exciting.