> For the complete documentation index, see [llms.txt](https://developers.tezos.domains/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.tezos.domains/interoperability/buys-and-renewals.md).

# Buys & Renewals

### Contract: TLDRegistrar.Commit

Creates a commitment to buy a second-level domain without disclosing the actual name. This is implemented according to our [commit\&reveal](https://en.wikipedia.org/wiki/Commitment_scheme) scheme.

**Entrypoint**: `commit`

| Parameter Type | Description                                                                                                                                                                                                                                                                                                                                                 |
| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `bytes`        | SHA-512 hash of a packed tuple of **label**, **owner**, and a **random nonce** corresponding to the intended buy (see [TLDRegistrar.Buy](/interoperability/buys-and-renewals.md#contract-tldregistrar-buy)). The hashed tuple is of the Michelson type`pair (pair bytes address) nat`. Having a random nonce prevents susceptibility to dictionary attacks. |

{% tabs %}
{% tab title="CamelLIGO" %}

```ocaml
type commit_param = bytes

| Commit of bytes
```

{% endtab %}

{% tab title="Michelson" %}

```
parameter (or
  (bytes %commit)
  # ... more entrypoints outside of this interoperability spec
);
```

{% endtab %}
{% endtabs %}

| Error              | Description                                                                     |
| ------------------ | ------------------------------------------------------------------------------- |
| AMOUNT\_NOT\_ZERO  | The transferred **amount** of *tez* is not zero.                                |
| COMMITMENT\_EXISTS | The given commitment exists. A commitment with a new nonce has to be generated. |

### Contract: TLDRegistrar.Buy

Buys a second-level domain based on previous commitment (see [TLDRegistrar.Commit](/interoperability/buys-and-renewals.md#contract-tldregistrar-commit)).

**Entrypoint**: `buy`

**Amount restriction**: The amount sent with this call has to be equal to the price of the domain. The price in mutez is calculated as `standard_price_per_day * duration / 1000000`.

| Parameter    | Type                  | Description                                                               |
| ------------ | --------------------- | ------------------------------------------------------------------------- |
| **label**    | `bytes`               | The UTF-8 encoded label of the second-level domain to buy.                |
| **duration** | `nat`                 | Ownership duration represented in days.                                   |
| **owner**    | `address`             | The new owner of the given domain.                                        |
| **address**  | `address option`      | The optional address the given domain resolves to.                        |
| **data**     | `(string, bytes) map` | A map of any additional data clients wish to store with the given domain. |
| **nonce**    | `nat`                 | The chosen commitment nonce.                                              |

{% tabs %}
{% tab title="CamelLIGO" %}

```ocaml
type buy_param = {
    label: bytes;
    duration: nat;
    owner: address;
    address: address option;
    data: (string, bytes) map;
    nonce: nat;
}

| Buy of buy_param michelson_pair_left_comb
```

{% endtab %}

{% tab title="Michelson" %}

```
parameter (or
  (pair %buy (bytes %label)
    (pair (nat %duration)
      (pair (address %owner)
        (pair (option %address address)
          (pair (map %data string bytes) (nat %nonce))))))
  # ... more entrypoints outside of this interoperability spec
);
```

{% endtab %}
{% endtabs %}

| Error                        | Description                                                                                                                                       |
| ---------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- |
| COMMITMENT\_DOES\_NOT\_EXIST | Corresponding commitment (see [TLDRegistrar.Commit](/interoperability/buys-and-renewals.md#contract-tldregistrar-commit)) was not created before. |
| COMMITMENT\_TOO\_OLD         | The commitment is too old (older than configured age). Try recreating it again.                                                                   |
| COMMITMENT\_TOO\_RECENT      | The commitment is too recent (younger than configured age). Wait for some time.                                                                   |
| LABEL\_TAKEN                 | The requested **label** already exists and it is not expired.                                                                                     |
| LABEL\_NOT\_AVAILABLE        | The requested **label** is currently not available for registration.                                                                              |
| LABEL\_IN\_AUCTION           | The requested **label** is currently only available in auction.                                                                                   |
| INVALID\_LABEL               | The given **label** is not valid. See [Label Validation](/interoperability/domain-operations.md#label-validation).                                |
| LABEL\_EMPTY                 | The given label is empty.                                                                                                                         |
| LABEL\_TOO\_LONG             | The label is too long.                                                                                                                            |
| NAME\_TOO\_LONG              | The name (label + parent) is too long.                                                                                                            |
| DURATION\_TOO\_LOW           | The requested **duration** is too low (lower than the configured minimum).                                                                        |
| AMOUNT\_TOO\_LOW             | The transferred **amount** is lower than the actual price.                                                                                        |
| AMOUNT\_TOO\_HIGH            | The transferred **amount** is higher than the actual price.                                                                                       |

### Contract: TLDRegistrar.Renew

Renews second-level domain for requested duration.

**Entrypoint**: `renew`

**Amount restriction**: The amount sent with this call has to be equal to the price of the domain. The price in mutez is calculated as `standard_price_per_day * duration / 1000000`.

| Parameter    | Type    | Description                                                |
| ------------ | ------- | ---------------------------------------------------------- |
| **label**    | `bytes` | The UTF-8 encoded label of the second-level domain to buy. |
| **duration** | `nat`   | The renewal duration represented in days.                  |

{% tabs %}
{% tab title="CamelLIGO" %}

```ocaml
type renew_param = {
    label: bytes;
    duration: nat;
}

| Renew of renew_param michelson_pair_left_comb
```

{% endtab %}

{% tab title="Michelson" %}

```
parameter (or
  (pair %renew
    (bytes %label)
    (nat %duration))
  # ... more entrypoints outside of this interoperability spec
);
```

{% endtab %}
{% endtabs %}

| Error              | Description                                                                                |
| ------------------ | ------------------------------------------------------------------------------------------ |
| LABEL\_NOT\_FOUND  | The requested **label** does not exist.                                                    |
| LABEL\_EXPIRED     | The requested **label** exists but it is expired. Therefore it can be bought, not renewed. |
| DURATION\_TOO\_LOW | The specified **duration** is too low (lower than the configured minimum).                 |
| AMOUNT\_TOO\_LOW   | The transferred **amount** is lower than the actual price.                                 |
| AMOUNT\_TOO\_HIGH  | The transferred **amount** is higher than the actual price.                                |