Final answer:
Passwords are the most common type of knowledge consisting of secret words or character combinations associated with an individual, used for cybersecurity.
Step-by-step explanation:
The most common type of possessed knowledge, comprising secret words or character combinations associated with an individual, are known as passwords. Passwords are a critical component of cybersecurity and are used to protect access to various digital accounts and systems, further ensuring the safety of personal and sensitive information. They act as a knowledge-based authentication mechanism where the correct combination of characters verifies the user's identity and grants access. It's a common form of propositional knowledge, which is the knowledge of facts, in this case, the fact that a specific sequence of characters (a password) is associated with the right to access certain information or systems.