crossbell-blog

*by @bcfh*

## TL; DR

Character-Bound Tokens are non-transferable NFTs that are bound to [characters](https://github.com/Crossbell-Box/Crossbell-Contracts/wiki/03-Detailed-Design#character), which present achievements and unique experiences that you complete or have on Crossbell.

## What are Character-Bound Tokens(CBTs)

The concept of CBTs originates from Soulbound Tokens(SBT). SBTs are bound to souls(people's identities) and CBTs are bound to characters(users' identities). SBT is a new kind of token standard that was first introduced by Vitalik Buterin, and it's built for a kind of scenario where it doesn't really matter how much money you can bid for NFTs, but it matters what you've done and what you've accomplished(eg. driver's licenses, university degrees, or killing some extremely difficult monsters in multiplayer online games).

CBTs serve the same purpose. Crossbell is an ownership platform served mainly for social activities, and every application wanting to issue credentials for user engagements or accomplishments should use CBTs standard. For example, [Crossbell.io](http://crossbell.io/) is an official application that runs on Crossbell chain, and its achievement NFTs are good examples of how CBTs can be used. Achievement NFTs celebrate and showcase users' journey on Crossbell by issuing erc1155 tokens to characters who completed specific requirements(like having enough followers or likes).

Because social activities on [crossbell.io](http://crossbell.io/) are initiated by characters as the main body, the CBTs are minted to characters and bound to them. Those achievements can't be sold or transferred alone unless you transfer the whole characters along with CBTs that are bound to them, which makes CBTs non-transferable in a way.

## How do CBTs work

Crossbell is social blockchain that is different from Ethereum or other public chains. On Ethereum, it's a common behavior for people to create multiple addresses representing different identities on a variety of occasions. For example, people might create new addresses specifically to interact with a Dex or a NFT project. It may be for asset safety reasons but it really brings a lot of trouble because you have to manage a lot of addresses their corresponding private keys and promise that they don't get leaked or fall into disorder. On Crossbell, you never have to keep multiple addresses and private keys, you just need to hold one address and one private key, because you can create multiple characters and use different characters to interact with different applications, which brings native advantages for Crossbell to support non-transferable feature.

When issuing, CBTs are minted to characters so they are bound to characters and they’re belonging to characters. Transfer functions are limited so you can’t transfer CBTs unless you transfer the whole characters.

```jsx
function safeTransferFrom(
        address,
        address,
        uint256,
        uint256,
        bytes memory
    ) external virtual override {
        revert("non-transferable");
    }

    /**
     * @dev See {IERC1155-safeBatchTransferFrom}.
     */
    function safeBatchTransferFrom(
        address,
        address,
        uint256[] memory,
        uint256[] memory,
        bytes memory
    ) external virtual override {
        revert("non-transferable");
    }
```

As shown above, when transfer functions are called, it reverts with an error message: non-transferable.

## Closing thoughts

The concept of Non-transferable Tokens is trending, but there are still many unexplored aspects that need to be considered carefully in the process of implementation, but we at Crossbell would like to be pioneers and gradually refine and popularize this concept during practice.

Character Bound Tokens

###  The Dream She Disseminates

Crossbell is an ownership platform, released in May this year. Though we have [posted a tweet](https://twitter.com/_Crossbell/status/1534705527070105601) about Crossbell before, we have been, in general, very humble and low-key about it. An important reason behind it is the fact that we have not prepared an application that can intuitively convey the ideologies of Crossbell. And now…here she comes!

Before introducing corssbell.io, we have to come back to this important question: what do we want to convey?

The ideologies behind Crossbell come from the mission of its parent company, Natural Selection Labs: “Liberate the Information Society”. And Crossbell focuses on social activities, trying to help users achieve that ultimate goal by taking back their data ownership.

[crossbell.io](https://crossbell.io), as the first official application from the Crossbell team, obviously has the goal to show out the ideology of “own your social activities”, and to make sure people feel it while socializing. However, please do not take it as a simple GUI to browse on-chain data or help convert off-chain data on-chain. Not at all. Crossbell.io is an independent product with her own ambitions and dream, also her own characteristics and spirit.

Forgive me if I am a bit offensive, but unspoken truth is that, in this ecosystem of Web3, especially regarding social applications, there is little “usability”. However, [crossbell.io](https://crossbell.io/)
 is an attempt that offers users the ability to be dynamic in their usage, without giving up the core values of Web3. At this special time when faith starts to crumble and narratives start to collapse, we want to make sure that we carry a stabilized mindset and keep buidling. We want crossbell.io to prove that we can deliver great user experience with pure decentralized Web3 infrastructures. And we also want to explore more possibilities implied by the operability of Web3 in terms of product. We want to figure out the “best practice” for Web3 applications. 

The ideal form for Web3 products remains unexplored. And the way we cross the chasm will never be behind closed doors. If collaborative building is one of the core values of Web3, I’d love to see [crossbell.io](https://crossbell.io) grow with the community, and that the ultimate product will be the result of our collaborative exploration.

I wish that the descriptions above will give you a brief sense about the characteristics of Crossbell and crossbell.io. A more detailed manifesto will be published soon.

## The Features She Decorates

Before crossbell.io, we already had an ecosystem application, CrossSync. It allows you to sync your tweets on-chain. This only shows what Crossbell is capable of: we can create a parallel universe with complete data ownership, with little effort. But we still need a more comprehensive application with more features, to help us explore, socialize, or even trade in this universe.

For friends that are not quite familiar with Crossbell, let me briefly introduce an important concept before moving to the features of crossbell.io: Character. The Character is the basic unit for users to socialize in Crossbell - we can set the name, handle, avatar, and bio for our Character. Every Character is an NFT. Users need to connect their Ethereum wallets in the beginning to mint a Character. And then they can socialize by committing “follow”, “like”, and “comment” actions. Of course, you can always get the $CSB you need from the faucet. And there is no limit on how many Characters an Ethereum address can hold.

Now let’s come back to the features of crossbell.io.

### *Feed*

As a social app, displaying content is most basic feature. On one hand, you could see all the content created by your followings; on the other hand, there is content from editors’ choice in the explore section.

We know that “explore” can be a bit controversial since lots of them are associated with “evil” algorithms. So here, we chose to do it meticulously with manual selections. It is just a way for people to know what is trending in the Crossbell theater.

Every Character can comment, like or mint toward any note on crossbell.io. But remember, these social activities are on-chain activities conducted by your character, which means that these actions will require you to connect a wallet and confirm transactions.

### *Shop*

As an NFT, a Character is tradable. Though this feature isn’t live yet, stay tuned!

### *Sync*

Wait... you might have noticed that, there's no content creation section on [crossbell.io](https://crossbell.io). That's true and we did it on purpose. We position crossbell.io as the product that helps users to freely explore this parallel universe that has been already established. And to gather data for this universe, expect for ecosystem apps, we will be primarily rely on the upcoming sync feature. It will help users to automatically sync their social media content on-chain. Once again, stay tuned!

## The Posture She Chooses

When we first started conceptualizing this app, we thought that Feed and Shop can be two separate applications. But as we proceeded, we believed more in the possibility that, in the world of Web3, the boundary between a social media and an NFT marketplace would be extremely blur. So we decided to make it as one app and replace our original official website [https://crossbell.io](https://crossbell.io/).

Honestly, this is exactly an exploration we make toward the form of product for Web3. We wish to eventually provide a user experience where people would naturally look up feed and also trading Characters.

In addition, the fact that it replaces a so-called “formal website” is also a bold attempt. We believe that she is extensible enough to cover all the information needed in a traditional website. She is flexible and interactive enough to become the main entrance as she herself is self-explanatory enough for all the ideas Crossbell stands for.

## One More thing......

In fact, the dream carried by Crossbell is not from nowhere. It was conceptualized a year ago and partially demonstrated in the PreNode stage of RSS3. While RSS3 focuses information dissemination with emphasis on feed, the social graph that used to be on PreNode is a precious treasury that should be migrated onto Crossbell, and continue to exercise the ideology of “own your social activities”. And [here](https://migrate.crossbell.io/) for the migration.

—— Atlas & The Crossbell Team

Crossbell is an ownership platform, released in May this year. Though we have posted a tweet about Crossbell before, we have been, in genera

Character Bound Tokens

Here Comes crossbell.io