Issuing assets on Byteball

tonyofbyteball edited this page May 21, 2018 · 7 revisions

To start a user-defined asset on Byteball, you need to complete two steps

  • Define your asset. Asset definition is a special type of message (distinct from payments) that you send to the Byteball DAG
  • Issue the asset by sending the 1st transaction that spends it

Defining a new asset

See a sample of asset-defining transaction at https://github.com/byteball/headless-byteball/blob/master/play/create_asset.js.

To define a new asset you need a headless wallet. In your dependencies:

"dependencies": {
	"headless-byteball": "git+https://github.com/byteball/headless-byteball.git",
	"byteballcore": "^0.2.33",
	.....
}

In your module:

var headlessWallet = require('headless-byteball');

Then, call this function to create a new asset definition:

var composer = require('byteballcore/composer.js');
composer.composeAssetDefinitionJoint(my_address, asset, headlessWallet.signer, callbacks);

Here my_address is your address you use to post the asset-defining message. The address must be funded to pay at least the transaction fees (about 1000 bytes).

asset is a javascript object that describes the properties of your asset. Here is an example:

var asset = {
	cap: 1000000,
	is_private: false,
	is_transferrable: true,
	auto_destroy: false,
	fixed_denominations: false,
	issued_by_definer_only: true,
	cosigned_by_definer: false,
	spender_attested: false
}

cap is the total number of coins that can be issued (money supply). If omitted, the number is unlimited.

is_private: indicates whether the asset is private (such as blackbytes) or publicly traceable (similar to bytes).

is_transferrable: indicates whether the asset can be freely transferred among arbitrary parties or all transfers should involve the definer address as either sender or recipient. The latter can be useful e.g. for loyalty points that cannot be resold.

auto_destroy: indicates whether the asset is destroyed when it is sent to the definer address.

fixed_denominations: indicates whether the asset exists as coins (banknotes) of a limited set of denominations, similar to blackbytes. If it is true, the definition must also include property denominations, which is an array of all denominations and the number of coins of that denomination:

var asset = {
	....
	fixed_denominations: true,
	denominations: [
		{denomination: 1, count_coins: 1e10},
		{denomination: 2, count_coins: 2e10},
		{denomination: 5, count_coins: 1e10},
		{denomination: 10, count_coins: 1e10},
		{denomination: 20, count_coins: 2e10},
		{denomination: 50, count_coins: 1e10},
		{denomination: 100, count_coins: 1e10},
		{denomination: 200, count_coins: 2e10},
		{denomination: 500, count_coins: 1e10},
		{denomination: 1000, count_coins: 1e10},
		{denomination: 2000, count_coins: 2e10},
		{denomination: 5000, count_coins: 1e10},
		{denomination: 10000, count_coins: 1e10},
		{denomination: 20000, count_coins: 2e10},
		{denomination: 50000, count_coins: 1e10},
		{denomination: 100000, count_coins: 1e10}
	]
};

issued_by_definer_only: indicates whether the asset can be issued only by the definer address. If false, anyone can issue the asset, in this case cap must be unlimited.

cosigned_by_definer: indicates whether each operation with the asset must be cosigned by the definer address. Useful for regulated assets where the issuer (bank) wants to perform various compliance checks (such as the funds are not arrested by a court order) prior to approving a transaction.

spender_attested: indicates whether the spender of the asset must be attested by one of approved attestors. Also useful for regulated assets e.g. to limit the access to the asset only to KYC'ed users. If true, the definition must also include the list of approved attestor addresses:

var asset = {
	....
	spender_attested: true,
	attestors: ["ADDRESS1", "ADDRESS2"]
};

The definition can also include two optional properties issue_condition and transfer_condition which specify the restrictions when the asset can be issued and transferred. They evaluate to a boolean and are coded in the same smart contract language as address definitions.

var asset = {
	....
	issue_condition: ["and", [
		["has one", {what: "output", asset: "this asset"}],
		["has", {what: "output", asset: "base", address: "MO7ZZIU5VXHRZGGHVSZWLWL64IEND5K2"}],
		["has one equal", {
			equal_fields: ["amount"], 
			search_criteria: [{what: "output", asset: "base"}, {what: "output", asset: "this asset"}]
		}]
	]],
	transfer_condition: ["and", [
		["has one", {what: "output", asset: "this asset"}],
		["has one equal", {
			equal_fields: ["address", "amount"], 
			search_criteria: [{what: "output", asset: "base"}, {what: "output", asset: "this asset"}]
		}]
	]]
};

The above conditions stipulate that the newly defined asset can be issued if the issuer also sends equal amount of bytes to the address MO7ZZIU5VXHRZGGHVSZWLWL64IEND5K2, and it can be transferred if equal amount of bytes is transferred to the same address at the same time.

Asset ID

After an asset is defined, the hash of the unit where it was defined becomes the unique ID of the asset. The asset is referenced by this ID in future payments and definitions (smart contracts). There are no user-assignable names of assets in the protocol, but there are independent registries that link asset IDs to user-friendly names for a fee. One such registry is https://byteball.market/.

Issuance of a new asset

The new asset can be issued after its definition is confirmed. To issue, you need just to spend the asset from an address that is allowed to issue (usually issued_by_definer_only: true, in this case, it is the definer address), and it will be issued automatically.

You cannot use wallet.sendMultiPayment(), headlessWallet.issueChangeAddressAndSendPayment() and similar functions because they can do only transfers and they don't know about addresses that can issue new coins. Instead, you have to use lower level functions:

See an example of how an asset can be both defined and issued in a single script https://github.com/byteball/ico-bot/blob/master/scripts/issue_tokens.js

Whitepaper

For more details see chapter 24 of the whitepaper.

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