public com.google.cloud.iot.v1.DeviceCredentialOrBuilder getCredentialsOrBuilder(int index) {
    return credentials_.get(index);
  }
public com . google . cloud . iot . v1 . DeviceCredentialOrBuilder getCredentialsOrBuilder ( int index ) { return credentials_ . get ( index ) ; }
<pre>
The credentials used to authenticate this device. To allow credential
rotation without interruption, multiple device credentials can be bound to
this device. No more than 3 credentials can be bound to a single device at
a time. When new credentials are added to a device, they are verified
against the registry credentials. For details, see the description of the
`DeviceRegistry.credentials` field.
</pre>

<code>repeated .google.cloud.iot.v1.DeviceCredential credentials = 12;</code>