What do ArcSoft official website mean by face matching (1: 1) and face retrieval (1:N)?

1: 1 means to compare yourself with yourself and see if you are you. For example, if you need ID card authentication, you need to ensure that the photos on the ID card are consistent with the face to be authenticated.

1: n indicates the comparison between individuals and faces in the face database. You know who you are in the crowd, for example, you can only brush your face in a company. By comparing your avatar with their company's face database, if there is one, you can enter it. If not, you have no access to the company.