In class, we (briefly) discussed four categories of authentication factors. A two-factor authentication scheme combines elements from two separate categories. Describe two DIFFERENT examples of valid two-factor authentication schemes (each scheme should use a unique pair of categories; in other words, if your first scheme uses categories A and B, your second scheme MUST have at least one item from category C or D).

hint:Answers will vary, but each answer should include two elements taken two different categories: things you know (e.g., passwords, security questions), things you have (e.g., physical security tokens like ID cards), things you are (e.g., biometric properties like fingerprints and voiceprints), and location-based security.