I found the topic of operating system security very interesting. I learned that in order for a computer to grant access to an entity, the computer must first establish trust with that entity. The computer establishes trust with the user through, what the entity knows, what the entity has, or what the entity is. An example of what the entity knows, is a password. An example of what the entity has, is a key card. This kind of security can be seen all over campus. We use a password to log into our student accounts, email, and facebook. We use both passwords and a key card to gain entrance to our residence hall or academic buildings after hours. These security precautions keep people that shouldn't have access out. One question that I have is how often should one change his/her password?