# Username and Password

You can authenticate one or more clients using username and passwords. This enables you to have greater control on the management and issuing of credential secrets.

For a single user:
```
authorization: {
	user: a,
	password: b
}
```

You can also specify a single username/password by:

```
> nats-server --user a --pass b
```

For multiple users:
```
authorization: {
	users: [
		{user: a, password: b},
		{user: b, password: a}
	]
}
```

## Bcrypted Passwords

Username/password also supports bcrypted passwords using the [`mkpasswd`](/nats_tools/mkpasswd.md) tool. Simply replace the clear text password with the bcrypted entries:

```
> mkpasswd
ass: (Uffs#rG42PAu#Oxi^BNng
bcrypt hash: $2a$11$V1qrpBt8/SLfEBr4NJq4T.2mg8chx8.MTblUiTBOLV3MKDeAy.f7u
```
And on the configuration file:

```
authorization: {
	users: [
		{user: a, password: "$2a$11$V1qrpBt8/SLfEBr4NJq4T.2mg8chx8.MTblUiTBOLV3MKDeAy.f7u"},
		...	
	]
}
```

## Reloading a Configuration

As you add/remove passwords from the server configuration file, you'll want your changes to take effect. To reload without restarting the server and disconnecting clients, simply do:

```
> nats-server --signal reload
```