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SBT is like an NFT but with several differences.

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Without transfer

The owner is set at mint time and never changes. Below is a simple explanation of the key operations and their message flows.

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Prove ownership

Allows the owner to ask the SBT to send a proof to a target contract confirming that they own this SBT. You may include arbitrary forward_payload and optionally attach content.
TL-B
;; Inbound message to SBT
prove_ownership#04ded148 query_id:uint64 dest:MsgAddress
  forward_payload:^Cell with_content:Bool = InternalMsgBody;

;; SBT response to the target contract (if checks pass)
ownership_proof#0524c7ae query_id:uint64 item_id:uint256 owner:MsgAddress
  data:^Cell revoked_at:uint64 content:(Maybe ^Cell) = InternalMsgBody;
  • query_id: arbitrary request identifier
  • dest: address of the target contract to prove ownership to
  • forward_payload: arbitrary data for the target contract
  • with_content: if true, attach SBT content
  • revoked_at: revoke time if SBT is revoked, 0 otherwise
Rejected if the sender is not the owner.

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Request current owner

Any initiator may ask the SBT to send the current owner (and optionally the content) to a target contract.
TL-B
;; Inbound message to SBT
request_owner#d0c3bfea query_id:uint64 dest:MsgAddress
  forward_payload:^Cell with_content:Bool = InternalMsgBody;

;; SBT response to the target contract
owner_info#0dd607e3 query_id:uint64 item_id:uint256 initiator:MsgAddress owner:MsgAddress
  data:^Cell revoked_at:uint64 content:(Maybe ^Cell) = InternalMsgBody;
  • initiator: address of the requester
  • Other fields mirror prove_ownership

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Destroy the contract

The owner can destroy the SBT contract. This clears the owner and authority fields, and sends remaining balance back to the sender via an excesses message.
TL-B
;; Internal message to SBT
destroy#1f04537a query_id:uint64 = InternalMsgBody;

;; Excess returned to the sender
excesses#d53276db query_id:uint64 = InternalMsgBody;
Rejected if the sender is not the owner.

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Revoke SBT

The authority can mark the SBT as revoked. Double-revoke is disallowed.
TL-B
;; Inbound message to SBT
revoke#6f89f5e3 query_id:uint64 = InternalMsgBody;
Rejected if:
  • the sender is not the authority;
  • the SBT was already revoked.

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Quick field reference

  • item_id: identifier of the SBT item (analogous to an NFT item)
  • owner: current owner
  • authority: the address allowed to revoke the SBT
  • content: SBT content (may be attached optionally)
  • revoked_at: Unix timestamp of revoke (0 means not revoked)
See more:
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