Two Step Authentication
It involves two processes of authentication of same type. Based on “What You Know” and “What You Know”. For example, the authentication involved Password and Security question. Both of them are belongs to the “What You Know” category.
Two Factor Authentication
This type authentication makes use of two factors like “What You Know” and “What You Have”. Let’s while doing a bank transaction. We have to input our password, which belong to “What You Know” and an OTP sent to our mobile or need to scan the finger print, which is “What You Have”.
Two factor authentication is normally more secure than the two step authentication.