PlatON Column | Soul Bound Tokenwho am I?

PlatON Network
6 min readOct 20, 2022

Author: James QU@Tokyo

Can you tell the difference between twins? I think you can, even if they are twins with the same DNA, so-called identical twins. Why? From the very beginning of their lives, they absorb energy separately, act independently in different ways, receive feedback in different ways, process the same and different inputs separately, and acquire completely different experiences. All these different experiences build different personalities and ultimately different people.

Today I want to talk about “Soul Bound Tokens” (aka SBT), where I am imagining my body as a virtual wallet, where everyday experiences can be described as tons of “SBT” poured into my wallet, some trivial, some important, some of which I can control, some of which I really want to reserve, some of which I am dreaming to get rid of, some of which I might want to keep private, some of which is totally out of my control, and some of which I want to announce to the whole world. These are the features or requirements for SBTs.

Before digging into SBT details, let me share a little bit of blurred memory here, I think it is a boring afternoon in 2020. A few of us gathered in a WeWork meeting room in Shanghai. David ZOU who is a leading blockchain economist who graduated from Harvard is among us, I am the most aged one from the stone age. We were discussing if there is a way to establish a regulated DEX on Public chain which could open the wormhole between Public chain and traditional financial service. After hot brainstorming for a few hours, later joint by Lilin who is the founder of LatticeX Foundation, a new keyword ACT was coined, which stands for “Authorization & Certificate Token”. There were at least three papers published by David after that. I also came up with a high-level technical design of the ACT token on Alaya public chain in early 2021, where Alaya is the pioneer of PlatON network. Now I realize that the ACT token is actually a Soul Bound Token, it belongs to category one below based on my categorization.

SBT categories

I tried to describe it in terms of a triad of elements here so can cover a bigger scope than the original paper[] covered.

There are three factors here <issuer, owner, controlMode>Where
issuer is one from {self, other}
owner as well should be one from (self, other).
controlMode means there are multiple ways how the SBT should be alike, there
are four ways as below
- issuer complete control, we could call it IC mode
- owner complete control, we could call it OC mode
- no control, simple NC mode
- algorithmic control, we can name it AC mode

The word “ControlMode” (IC, OC, NC, AC) means the actions can be done against the minted SBT, to revoke, expire, or transfer is out of scope by default since we are talking about SBT.

From the above scope, we could have below different types SBTs

1. <issuer, other, IC> : Issuer mints SBTs to others, issuer has complete control
2. <issuer, other, OC> : Issuer mints SBTs to others, others have complete control
3. <issuer, other, NC> : Issuer mints SBTs to others, no control
4. <issuer, issuer, AC> : Issuer mints SBTs to itself, algorithm control (e.g. expire when meet certain criteria )
5. <issuer, other, AC> : Issuer mints SBTs to others, algorithm control (e.g. expire when meet certain criteria )

Ignoring below two cases for now, since they are quite straightforward

1. Issuer mints SBTs to itself, the issuer has complete control
2. Issuer mints SBTs to itself, with no control

Where complete control means ( revoke, expire, other actions you may think of ), etc, depending on the protocol.

ACT token for regulated financial services

The ACT token actually fails into above category #1 <issuer, other, IC> , where an issuer has full control of SBTs after “mint” for target wallets. Let’s consider regulated financial service for the use case.

In this case, as we discussed in that hot afternoon, the issuer or issuers are institutions or government branches who pass KYC as regulators in the traditional financial service sector. It could mint a special SBT to announce itself as THE regulator, both on-chain and off-chain.

Then the issuer will mint different types of SBTs to group of wallets which in turn must pass the KYC of the issuer’s procedure, which means these group of wallets are equivalent to licensed financial service providers.

Different SBTs refer to different financial service licenses, so those wallets can build and own different kinds of smart contract financial services, such as money lending, DEX service, etc.

Medical case

Similarly, certified public hospital entities could mint different types of SBTs to the patient wallets, using category #1 <issuer, other, IC>. The medical history and allergy etc will follow and protect the patient for lifetime. When a patient participates in the symptoms sharing program (of cause, will be protected by privacy-preserving AI platform such as Datum, PlatON combination), the KYCed medical pharmacies could mint contributor SBTs to the patient wallets. Those SBTs will bring new medicine discount coupons and other benefits later.

Education, military service, charities and working experience

For education, military, charity and working experience, I would suggest using category #2 <issuer, other, OC> . Certified universities, military institutions, NGOs, charity groups, training agencies, and fi rms could mint SBTs with rich metadata attributes. The individual could control which part to disclose. I may want to destroy the ones i failed pass exams, and high light those I did well in education areas. For military area, I may pick up those tough experience as proof of mental strength.

Sports memberships, entertainment memberships etc

Any entertainment group or sports club can design a variety kinds of SBTs, I may want to get a MVP title SBT, which could bring me a free golf membership with an expiration date in three years, for example. In this case, this history is still history. The benefit has a valid period. This can be done by category #1 or #2.

The decentralized social network by Souls

I believe there are a lot of interesting use cases we can imagine. The key is SBTs could build up a complicated, cross certified social network. Individual will be more independent, less bounded to firms, with more freedom and more creative potential. This is a healthy decentralized society I would like to enjoy.

The charity action of donating to a digital ID (wallet) leading project based on SBTs will be a true charity, and you may get a SBT in return, which will prove of your contribution when the project success. I do see the open-door freedom cooperation there.

The Algorithm control mode

For category #4 <issuer, issuer, AC> and #5 <issuer, other, AC>, especially #5, will help the transfer of dominate AI to democratic AI which PlatON and LatticeX are heading towards. Will share more thoughts on this in next articles if I could write more.

The Binance practice

Looked the Binance practice, it is more looks like a implementation of ERP-4973. With rich community activities, will close follow how far they plan to go.

The Challenges

Digital identity, as simple as a digital wallet, is not yet for everyone. There are many people who cannot enjoy digital metaverse and are still far from the doorway.

Next time, will dig into more details of ACT design, share my aged memory and thoughts with you.


  • Decentralized Society: Finding Web3’s Soul
  • David ZOU : 公链如何⽀持合规⾦融应⽤? — — 基于ACT的解决⽅案
  • David ZOU : 区块链研究2021年第13期(总第110期)合规⾦融应⽤中的FT与NFT以及对“Alaya+ACT”的启⽰
  • David ZOU : 区块链研究2021年第12期(总第109期)合规⾦融应⽤对“公链+ACT”的要求
  • Binance: What are SoulBound Tokens
  • ERP-4973



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