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$$ \newcommand \MinBalance {b_{\min}} $$

Asset Transaction Semantics

Asset Configuration

An asset configuration transaction has the following semantics:

  • If the asset ID is zero, create a new asset with an ID corresponding to one plus this transaction’s unique counter value. The transaction’s counter value is the transaction counter field from the block header plus the positional index of this transaction in the block (starting from \( 0 \)).

On asset creation, the asset parameters for the created asset are stored in the creator’s account under the newly allocated asset ID. The creating account also allocates space to hold asset units of the newly allocated asset. All units of the newly created asset (i.e., the total specified in the parameters) are held by the creator. When the creator holding is initialized, it ignores the _default frozen_flag and is always initialized to unfrozen.

  • If the asset ID is non-zero, the transaction MUST be issued by the asset manager (based on the asset’s current parameters). A zero manager address means no such transaction can be issued.

    • If the asset parameters are omitted (the zero value), the asset is destroyed. This is allowed only if the asset creator holds all of the units of that asset (i.e., equal to the total in the parameters).

    • If the asset parameters are not omitted, any non-zero key in the asset’s current parameters (as stored in the asset creator’s account) is updated to the key specified in the asset parameters. This applies to the manager, reserve, freeze, and clawback keys. Once a key is set to zero, it cannot be updated. Other parameters are immutable.

Asset Transfer

An asset transfer transaction has the following semantics:

  • If the asset sender field is non-zero, the transaction MUST be issued by the asset’s clawback address, and this transaction can neither allocate nor close out holdings of an asset (i.e., the asset close-to field MUST NOT be specified, and the source account MUST already have allocated space to store holdings of the asset in question). In this clawback case, freezes MUST be bypassed on both the source and destination of this transfer.

  • If the asset sender field is zero, the asset sender is assumed to be the transaction’s sender, and freezes MUST NOT be bypassed.

  • If the asset amount is \( 0 \), the transaction allocates space in the sender’s account to store the asset ID. The holdings are initialized with a zero number of units of that asset, and the default frozen flag from the asset’s parameters. Space cannot be allocated for asset IDs that have never been created, or that have been destroyed, at the time of space allocation. Space can remain allocated, however, after the asset is destroyed.

  • The transaction moves the specified number of units of the asset from the asset sender to the asset receiver.

    • If either account is frozen, and freezes are not bypassed, the transaction fails to execute.

    • If either account has no space allocated to hold units of this asset, the transaction fails to execute.

    • If the asset sender has fewer than the specified number of units of that asset, the transaction fails to execute.

  • If the asset close-to field is specified, the transaction transfers all remaining units of the asset to the close-to address.

    • If the close-to address is not the creator address, then neither the asset sender’s holdings of this asset nor the close-to address’s holdings can be frozen; otherwise, the transaction fails to execute.

    • Closing to the asset creator is always allowed, even if the source and/or creator account’s holdings are frozen.

    • If the asset sender or close-to address does not have allocated space for the asset in question, the transaction fails to execute.

    • After transferring all outstanding units of the asset, space for the asset is deallocated from the sender account.

Asset Freeze

An asset freeze transaction has the following semantics:

  • If the transaction is not issued by the freeze address in the specified asset’s parameters, the transaction fails to execute.

  • If the specified asset ID does not exist in the specified account, the transaction fails to execute.

  • The freeze flag of the specified asset in the specified account is updated to the frozen status flag value from the freeze transaction.

Asset Allocation

When an asset transaction allocates space in an account for an asset, whether by creation or opt-in, the sender’s minimum balance requirement is incremented by \( \MinBalance \).

When the space is deallocated, whether by asset destruction or asset close-to, the minimum balance requirement of the sender is decremented by \( \MinBalance \).