When getting started with the Kadena public blockchain, the first thing you’ll want to do is create an account so you can start transacting with other users. This article will break down exactly what keys are, what an account is, the myriad ways to create one, and how to add your account to several existing tools. First, we’ll do an extremely high-level tour of public-key cryptography.

Keys are everywhere in blockchain land. You might at least be aware that to begin transacting in any network, you have to generate a public/private key-pair. Using this pair of keys, you generally share the public one and keep the private one secret, using the private key exclusively for signing transactions. If this is foreign to you, I suggest you take a look at this lovely StackOverflow summary of the metaphor. A key-pair is easy to generate, and looks a little like this:

Now, the fun part about public/private key-pairs is that a key-pair has the property that the secret key can “prove” you are the owner of the public key through a sophisticated dance (the underlying algorithm), and also has the incredible property that any given key-pair is almost universally guaranteed to be unique. No one will ever be able to produce an exact copy of either key by any reasonable means other than theft. I say “almost,” because there’s still a probabilistically minute chance that someone may end up generating the same key-pair as you, but the time it would take for that to happen is several trillion years from now, sometime around the Heat Death of the Universe — roughly the same probability as your computer spontaneously catching fire during the generation process.

In many blockchains, because of the global uniqueness of key-pairs, accounts are modeled as simply public/private key-pairs or a variation on the theme with additional data like a nonce. This is great and makes things simple, but it runs into problems very quickly from a philosophical standpoint. Consider the following question: what do key-pairs represent? Is it an individual? A couple? A throuple? A polycule? A board of directors? If it’s more than one person, what governs usage policy? Certainly, if a married couple decides to open up a joint bank account, it’d be terrible if one could drain the account and leave the other penniless and without recourse. Indeed, joint accounts require multiple-signature signing to release funds. In the same vein, a board of directors would vote, and a majority of votes would determine what to do with the funds of a company. Let’s call this idea governance predicate.

The metaphor works fantastically well for single-person, single-key-pair accounts, but breaks down in blockchains like Ethereum when a many-to-many relationship and finer-grained multiple-signature governance is needed. Much of the Ethereum ecosystem, for instance, is geared towards finding clever ways to shove the many-to-many idea into a many-to-one box, which ends up being costlier than it needs to be, and frankly, begs a better design. Oddly enough, Bitcoin handles multi-signature accounts just fine.

This brings us to the notion of Keysets in Kadena.

Kadena natively supports multiple keys governing the same account (multi-sig), so keysets are, to some degree, exactly what they sound like: a set of keys. In addition to a set of keys, every keyset contains something called a ‘predicate function’ that determines which keys are allowed to make choices for the account when it comes to transactions (do all keys need to be present? only one? two? etc.). Summarily, keysets look like the following as JSON data:

When signing a transaction, the list of private keys supplied as signing key pairs will be checked against the keyset and predicate to ensure that not only are all keys that need to be present accounted for but that the predicate is satisfied.

Predicate Functions

There are 3 out-of-the-box predicate functions that are available:

Smart contract authors are free to write their own predicate functions if they need more fine-grained functionality, but that is beyond the scope of this article. Feel free to read up more on predicates in the Pact readthedocs.

When Are Two Keysets the Same?

Two keysets are the same when all of their keysets match, and they have the same predicate function guarding the keys. This means that if you have an account defined in the coin contract as the following data:

And someone attempts to transfer-create (see: getting started with transfers) to your account (which checks the keyset against the one supplied by the sender) with the following data:

Then this will fail because the keyset governing the account is wrong, and the blockchain will see the transaction as someone using the wrong keys to try and access an account. If you imagine a board of directors sitting around and all of them have to be present to make a vote, but some bozo comes in trying to say only 1 of them needs to be there and the rest can go home, that person would be laughed out of the room! The same goes for keysets. Make sure the keys match exactly.

Kadena is unique in the fact that there is no global notion of what an account is. Even the KDA token exists as a smart contract in the network! It turns out that in the Kadena blockchain, every smart contract can define their own tables and interact with them in a robust way, defining their own data structures, called *schema. These schemas* are used inside the contract to define the table structure, and therefore the way the contract will store data. It just so happens that this is exactly what the KDA coin contract does — it defines a table called coin-table along with a schema called coin-schema , which defines the general model for interacting with tokens. The schema is rather simple — row keys are account names, and the data it points to are a balance and a set of keys governing the account. Visually, it looks like this:

In practice, many people are used to the model that blockchains like Ethereum or Bitcoin use, where public keys are considered an “address,” and there is an associated balance. This is very similar to what Kadena has. In fact, if you make your account name your public key, then it looks roughly the same:

But if you really want to get fancy, then you can have a custom name as your account name:

It doesn’t really matter — you just have to remember it! Practically, this is why people just go with a public key as their account name — it’s right there in the keys. As more sophisticated technology comes out supporting the Kadena ecosystem, and as wallet technology gets better and better, tracking this sort of thing will be taken care of automatically.

Account creation happens in the blockchain in a few ways:

Just creating a public key pair is not the same as creating an account in the blockchain, but it does guarantee that you have a unique account name. Cryptographically, public keys are almost guaranteed to be uniquely generated, so people often conflate the two.

Along with its blockchain, Kadena released a wallet for Mac, called Chainweaver, and this wallet allows you to create accounts easily with the click of a button. We’ve done a full write-up of how to create accounts, keys, and make use of the wallet’s numerous features here.

There you have it: this has been a tour of accounts! This is one of the more fundamental aspects of interacting with the Kadena blockchain, and I’m glad you took the time to read about it. We’ve made some great improvements to the way people interact with blockchains, supporting native multi-sig and custom smart contract table design, and we are happy to take on board any feedback you can give.

We also welcome help from the community for documenting these tools and constructing new ones along the way. We are always happy to rep community-blessed tools if they are better than our own. We welcome anyone to contribute to the Kadena Community projects repository with your own project or add to existing ones. So far, the community projects have yielded both a great terminal wallet with Bag of Holding, and a blazing fast GPU miner courtesy of Alex Khonovalov, Edmund Noble, and myriad other insanely smart community members.

Thanks to everyone who contributed, and please feel free to raise your questions to me in Discord — my handle is one of @topos, @pitopos, or @emilypi depending on where I am on the internet. I’m perpetually glued to my screen, so I’ll usually answer if you find me. In the event I’m sleeping, there may be a delay.