# About PIN

PIN stands for Personal Information Node. Each piece of on-chain data that conforms to the MetaID format is called a PIN. These are issued by users through private key signatures, representing individual on-chain actions. Actions such as creating a MetaID, posting comments, liking, deploying, and minting assets are all represented by a PIN.

PINs use ordinal theory, with the PIN content loaded in the transaction output, typically at the first satoshi of its output. When a PIN is created, the first satoshi of the transaction output represents the PIN.

#### **PIN Owners and Creators**

Each **`PIN`** has two main attributes: owner and creator.

* **Creator**: The creator is the original address that generated the **`PIN`**. This attribute is determined by the transaction that creates the **`PIN`** and, once set, cannot be changed regardless of subsequent transactions.
* **Owner**: The owner is the current user address that holds the satoshi representing the **`PIN`**. This attribute can be changed by transferring the satoshi.

For example, if user address A creates a **`PIN`**, and the satoshi representing this

**`PIN`** is currently held by user address B, then A is the creator and B is the owner.

#### **PINID**

A **`PINID`** is composed of its transaction ID (**`TxId`**) and the output position (**`output index`**) within the transaction. The format is as follows:

```css
PINID = {TxId}i{index}
```

The **`PINID`** is a globally unique identifier, marking a specific position within a specific transaction on the blockchain.

#### **PIN Number**

The **`PIN Number`** is a sequence number assigned to a **`PIN`**. It is ordered based on the sequence in which the **`PIN`** is packaged in the blockchain, following the first-seen principle.

#### Transfer

The PINs in MetaID exist in the form of satoshis, allowing the tracking and transfer of individual satoshis. The transfer follows a first-in-first-out method from the transaction input to the transaction output, depending on the order of transaction inputs and outputs.

As shown in the diagram, if the PIN is in position #1001 in all transaction inputs, it remains in position #1001 in all transaction outputs after the transfer.

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