sing-box/docs/configuration/shared/tls.md

### Inbound

```json
{
  "enabled": true,
  "server_name": "",
  "alpn": [],
  "min_version": "",
  "max_version": "",
  "cipher_suites": [],
  "certificate": "",
  "certificate_path": "",
  "key": "",
  "key_path": "",
  "acme": {
    "domain": [],
    "data_directory": "",
    "default_server_name": "",
    "email": "",
    "provider": "",
    "disable_http_challenge": false,
    "disable_tls_alpn_challenge": false,
    "alternative_http_port": 0,
    "alternative_tls_port": 0,
    "external_account": {
      "key_id": "",
      "mac_key": ""
    }
  }
}
```

!!! warning ""

    ACME is not included by default, see [Installation](/#installation).

### Outbound

```json
{
  "enabled": true,
  "server_name": "",
  "insecure": false,
  "alpn": [],
  "min_version": "",
  "max_version": "",
  "cipher_suites": [],
  "certificate": "",
  "certificate_path": ""
}
```

TLS version values:

* `1.0`
* `1.1`
* `1.2`
* `1.3`

Cipher suite values:

* `TLS_RSA_WITH_AES_128_CBC_SHA`
* `TLS_RSA_WITH_AES_256_CBC_SHA`
* `TLS_RSA_WITH_AES_128_GCM_SHA256`
* `TLS_RSA_WITH_AES_256_GCM_SHA384`
* `TLS_AES_128_GCM_SHA256`
* `TLS_AES_256_GCM_SHA384`
* `TLS_CHACHA20_POLY1305_SHA256`
* `TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA`
* `TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA`
* `TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA`
* `TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA`
* `TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256`
* `TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384`
* `TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256`
* `TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384`
* `TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256`
* `TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256`

!!! note ""

    You can ignore the JSON Array [] tag when the content is only one item

### Fields

#### enabled

Enable TLS.

#### server_name

Used to verify the hostname on the returned certificates unless insecure is given.

It is also included in the client's handshake to support virtual hosting unless it is an IP address.

See [Server Name Indication](https://en.wikipedia.org/wiki/Server_Name_Indication).

#### insecure

==Client only==

Accepts any server certificate.

#### alpn

List of supported application level protocols, in order of preference.

If both peers support ALPN, the selected protocol will be one from this list, and the connection will fail if there is
no mutually supported protocol.

See [Application-Layer Protocol Negotiation](https://en.wikipedia.org/wiki/Application-Layer_Protocol_Negotiation).

#### min_version

The minimum TLS version that is acceptable.

By default, TLS 1.2 is currently used as the minimum when acting as a
client, and TLS 1.0 when acting as a server.

#### max_version

The maximum TLS version that is acceptable.

By default, the maximum version is currently TLS 1.3.

#### cipher_suites

The elliptic curves that will be used in an ECDHE handshake, in preference order.

If empty, the default will be used. The client will use the first preference as the type for its key share in TLS 1.3.
This may change in the future.

#### certificate

The server certificate, in PEM format.

#### certificate_path

The path to the server certificate, in PEM format.

#### key

==Server only==

The server private key, in PEM format.

#### key_path

==Server only==

The path to the server private key, in PEM format.

### ACME Fields

#### domain

List of domain.

ACME will be disabled if empty.

#### data_directory

The directory to store ACME data.

`$XDG_DATA_HOME/certmagic|$HOME/.local/share/certmagic` will be used if empty.

#### default_server_name

Server name to use when choosing a certificate if the ClientHello's ServerName field is empty.

#### email

The email address to use when creating or selecting an existing ACME server account

#### provider

The ACME CA provider to use.

| Value                   | Provider      |
|-------------------------|---------------|
| `letsencrypt (default)` | Let's Encrypt |
| `zerossl`               | ZeroSSL       |
| `https://...`           | Custom        |

#### disable_http_challenge

Disable all HTTP challenges.

#### disable_tls_alpn_challenge

Disable all TLS-ALPN challenges

#### alternative_http_port

The alternate port to use for the ACME HTTP challenge; if non-empty, this port will be used instead of 80 to spin up a
listener for the HTTP challenge.

#### alternative_tls_port

The alternate port to use for the ACME TLS-ALPN challenge; the system must forward 443 to this port for challenge to
succeed.

### Reload

For server configuration, certificate and key will be automatically reloaded if modified.

#### external_account

EAB (External Account Binding) contains information necessary to bind or map an ACME account to some other account known
by the CA.

External account bindings are "used to associate an ACME account with an existing account in a non-ACME system, such as
a CA customer database.

To enable ACME account binding, the CA operating the ACME server needs to provide the ACME client with a MAC key and a
key identifier, using some mechanism outside of ACME. §7.3.4

#### external_account.key_id

The key identifier.

#### external_account.mac_key

The MAC key.