See if we can use Citadel for Soulbound tokens

[xevisalle]

Soulbound tokens are items that can not be transferred or sold. We should see if Citadel would be a suitable model for this type of tokens.

[xevisalle]

Soulbound tokens are described in greater detail here: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4105763. In this paper, the authors explain the properties that a soulbound token should satisfy. We should:

• Summarize all the properties of a soulbound token.
• See if Citadel satisfies them.
• In case not, decide if we want to extend Citadel to fit the soulbound token framework.

[xevisalle]

SBTs is a definition done by some authors, which in essence means having a digital identity tied to an individual, that cannot be transfered. They define some other properties, but in essence, this is what is done in Citadel.

For what concerns one of the interesting properties, "soul recovery", it basically means setting a group of people you trust, the "guardians", and give them power over your account, or in other words, your "soul". This satisfies 2 approaches:

(1) If you don't remember you secret key, the "guardians" can help you to regenerate it.
(2) If someone got your secret key and is impersonating you, in account-based models like Ethereum, the guardians you previously set have the power (by consensus) of moving the account tied to your address, to a new address. In other words, guardians can directly change the secret keys of your wallet, by consensus.

In Citadel, approach (1) can easily be achieved by means of different approaches (i.e. trusting them a part of the key, multisigs, etc.). For what concerns (2), we also know an easy way achieve that, but by making a few changes to the protocol: making the license to be tied to a value different from npk. Maybe the nonce, but some research needs to be done.

[xevisalle]

Closing because in essence Citadel is already SBT, and any other related features are just implementation details.