使用硬件令牌进行登录

I am new to the topic of cryptography and am studying PKI and PKCS etc. I understand the basic concept of PKI and how it is used for encryption/decryption. I am confused however about how a hardware token like a USB token or a smartcard is used for secure login to your computer. Here are steps as I understand them and the part I am confused by (sorry in advance for the question length):I am new to the topic of cryptography and am st