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Asset Units

Every native asset on Cardano is identified by two components: a policy ID (28-byte hash of the minting policy script) and an asset name (0-32 bytes chosen by the minter). Together, these form the asset's unique identifier or "unit."

Structure​

ComponentSizeFormatExample
Policy ID28 bytesHex (56 chars)7edb7a2d...c9d8e7f6
Asset Name0-32 bytesHex-encoded4d79546f6b656e ("MyToken")
UnitCombinedpolicyId + assetName7edb7a2d...4d79546f6b656e

Working with Assets​

import { Assets } from "@evolution-sdk/evolution"

const policyId = "7edb7a2d9fbc4d2a68e4c9e9d3d7a5c8f2d1e9f8a7b6c5d4e3f2a1b0" // 56 hex chars = 28 bytes
const assetName = "4d79546f6b656e" // "MyToken" in hex

// Add native token to an asset bundle
let assets = Assets.fromLovelace(2_000_000n) // Min ADA for UTxO
assets = Assets.addByHex(assets, policyId, assetName, 1000n)

Lovelace​

ADA's smallest unit is lovelace. 1 ADA = 1,000,000 lovelace. Lovelace is always represented separately from native tokens in asset bundles:

import { Assets } from "@evolution-sdk/evolution"

const fiveAda = Assets.fromLovelace(5_000_000n)

// Common amounts
const oneAda = 1_000_000n
const halfAda = 500_000n
const tenAda = 10_000_000n

Minimum ADA​

Every UTxO must contain a minimum amount of ADA (determined by coinsPerUtxoByte protocol parameter). UTxOs with native tokens require more ADA because they're larger. The transaction builder calculates this automatically.

Next Steps​