The present invention relates to a device and method for authenticating users and obtaining user signatures, which can be provided in business services using networks and various user information devices including information devices equipped with touch displays such as smartphones, or desktop PCs, laptops, tablet PCs, CCTVs, IoT, self-driving cars, drones, etc. and, more specifically, to a device and method for authenticating users and obtaining user digital signatures which, as an encryption key/password generation and verification system for user authentication to be provided in various web-based businesses in which various information devices are serviced in a client-server or peer-to-peer model network environment and in app-based businesses running on a specific platform, is simpler and ensures confidentiality and security.