The FREE Cybersecurity Glossary by Thor Pedersen!

Key Risk Indicators (KRIs): Metrics used to measure and evaluate the risk level of an organization or system based on predetermined criteria and thresholds. It is used to identify, prioritize, and monitor potential risks to the organization's security and integrity. Examples of security-related KRIs include the number of vulnerabilities, the frequency of security incidents, and the level of access controls.

Key Space: In cryptography, key space refers to the set of all possible keys that can be used with a cryptographic algorithm, defining the limits of potential key values. The size of the key space (i.e., the total number of distinct keys) is determined by the key length, impacting the algorithm's resistance to brute force attacks. For example, a 128-bit keyspace has 2^128 possible keys.

Key Space Clumping: A phenomenon in cryptography where potential keys are unevenly distributed within the key space, creating clusters that may be more likely to be chosen or attacked. This can weaken cryptographic systems by reducing the effective key space size, making it more susceptible to brute force attacks. Robust cryptographic systems strive to avoid key space clumping to ensure the equal likelihood of all keys and maintain strong security.

Key Stretching: The process of applying a cryptographic function multiple times to a password or key to increase its effective length and security. It is used to protect against brute-force attacks and dictionary attacks by making it computationally infeasible to guess or crack the key. Examples of key stretching algorithms include PBKDF2 and Argon2.

KillDisk malware: A type of destructive malware that erases or corrupts data on a system, often used to disrupt operations or as part of a larger cyberattack. Examples of KillDisk attacks include attempts to extort money through data destruction threats or to cause system outages, such as the Petya and NotPetya incidents.

Kiosk service point: A physical location where customers can access a company's services or products, often through the use of a self-service terminal. It is commonly found in airports, shopping malls, and other public areas. Examples include a ticket kiosk at an amusement park or a rental car kiosk at an airport.