The FREE Cybersecurity Glossary by Thor Pedersen!

Kerberos: A network authentication protocol that uses tickets and encryption to securely identify users and grant them access to network resources. It is used to prevent unauthorized access and protect against replay attacks. It is used in network security and authentication. Examples include logging into a computer or accessing a database.

Key Distribution Center (KDC): A Key Distribution Center (KDC) is a network service that facilitates secure communication by issuing and managing cryptographic keys. It authenticates users and distributes session keys that enable users to encrypt and decrypt messages, ensuring secure communication across the network. It plays a critical role in protocols like Kerberos.

Kerckhoffs' Principle: Kerckhoffs' Principle states that a cryptographic system should be secure even if everything about the system is public knowledge, except for the key. It underlines the need for cryptographic algorithms to be open to scrutiny without compromising security, thereby placing the burden of secrecy solely on the key and not on the system's design.

Kernel mode: A mode of operation in an operating system where the system has complete control over the hardware and can execute any instructions. It is used for low-level tasks and is protected from user interference to prevent system instability. It is used in operating systems and computer architecture. Examples include managing memory or controlling device drivers.

Key-based authentication: A method of verifying a user's identity using cryptographic keys, typically involving a pair of public and private keys. It is used in various security protocols to ensure that access to resources is granted only to authenticated users.

Key clustering: Key clustering refers to a phenomenon in cryptography where different encryption keys produce the same ciphertext from the same plaintext. This can be viewed as a weakness in the encryption algorithm since it effectively reduces the number of unique keys and may allow an attacker more chances to find a key that decrypts the ciphertext successfully.