KBR: Key Based Routing
Key Based Routing (KBR) is a lookup method used in conjunction with distributed hash tables (DHTs). While DHTs provide a method to find a host responsible for a certain piece of data, KBR provides a method to find the closest host for that data, according to some defined metric. This may not necessarily be defined as physical distance, but rather the number of network hops. KBR improves the efficiency of decentralized information retrieval in peer-to-peer networks.

KCA: Key certification authority
Key certification authority (KCA) is a trusted entity that typically keeps a secure database of compound messages signed with the KCA's private key. In practical implementations, the compound messages consist of the user's name, the user's public key, and any other important information about the user. When the receiving application gets a signed message from a user, the application can then verify the public key received with the message by comparing it to the public key stored in the KCA database.

KDC: Key Distribution Center
The Key Distribution Center (KDC) is part of a cryptosystem intended to reduce the risks inherent in exchanging keys. The KDC is a single process that provides two services: Authentication Service (AS) and Ticket-Granting Service (TGS).

KDF: Key Derivation Function
A Key derivation function (or KDF) is a cryptographic hash function which derives one or more secret keys from secret values and/or other known information. Key derivation functions are often used in conjunction with non-secret parameters to derive one or more keys from a common secret value. Such use may prevent an attacker who obtains a derived key from learning useful information about either the input secret value or any of the other derived keys. A KDF may also be used to ensure that derived keys have other desirable properties, such as avoiding "weak keys" in some specific encryption systems.

KEK: Key-encrypting key
Key-encrypting key (KEK) is a type of cryptographic key that is used to encrypt other keys, either DEKs or other KEKs, but usually is not used to encrypt application data.

Kensington security slot
Kensington security slot is a physical connector found on laptop computers that is used to link locks and cables developed by Kensington.

Kerberos
Kerberos is a network authentication protocol. Kerberos is designed to provide strong authentication for client/server applications by using secret-key cryptography. This is accomplished without relying on authentication by the host operating system, without basing trust on host addresses, without requiring physical security of all the hosts on the network, and under the assumption that packets traveling along the network can be read, modified, and inserted at will.

Kerberos policy
Kerberos policy refers to the Group Policy settings for Kerberos authentication in Microsoft Windows 2000/2003.

Kernel
Kernel is the essential center of a computer operating system, the core that provides basic services for all other parts of the operating system. A kernel can be contrasted with a shell, the outermost part of an operating system that interacts with user commands. Kernel and shell are terms used more frequently in Unix and some other operating systems than in IBM mainframe systems.

Key
In cryptography, a key is a variable value that is applied using an algorithm to a string or block of unencrypted text to produce encrypted text, or to decrypt encrypted text. The length of the key is a factor in considering how difficult it will be to decrypt the text in a given message.

Key BLOB
Key BLOB is a BLOB containing an encrypted private key. Key BLOBs provide a way to store keys outside the CSP. Key BLOBs are created by exporting an existing key from the CSP by calling the CryptExportKey function. Later, the key BLOB can be imported into a provider (often a different CSP on a different computer) by calling the CryptImportKey function. This creates a key in the CSP that is a duplicate of the one that was exported.

Key BLOB format
Key BLOB format is the format of the key BLOB when a public or session key is exported from a CSP. The format is specified by the provider type of the exporting CSP. A key BLOB is created by calling CryptExportKey.

Key container
Key container is a part of the key database that contains all the key pairs (exchange and signature key pairs) belonging to a specific user. Each container has a unique name that is used when calling the CryptAcquireContext function to get a handle to the container.

Key database
Key database is a database that contains the persistent cryptographic keys for a specific CSP. The database contains one or more key containers, which individually store all the cryptographic key pairs for a specific user.

Key Distribution
Key Distribution is a process that delivers a cryptographic key from the location where it is generated to the locations where it is used in a cryptographic algorithm. One of the biggest practical problems in symmetric cryptography is the secure distribution of keys.

Key Distribution
Key distribution means passing the key from the encrypt party to the decrypt party. One of the biggest practical problems in symmetric cryptography is the secure distribution of keys.

Key Escrow
Key Escrow involves lodging the decryption key with a Trusted Third Party (TTP). It is an emotive subject because of governments' repeated attempts and known desire to enforce a general requirement not merely for key escrow, but also for the mandatory release of that key to Law Enforcement agencies. This raises civil liberties issues as well as security issues.

Key Establishment algorithm
Key Establishment algorithm is a process that combines the key generation and key distribution steps needed to set up or install a secure communication association.

Key exchange algorithm
Key exchange algorithm refers to an algorithm used to encrypt and decrypt exchange keys (symmetric session keys). Some common key exchange algorithms include DH(Diffie-Hellman algorithm) and KEA(Key Exchange Algorithm). Each provider type can specify only one key exchange algorithm.

Key Exchange Protocol
A key exchange protocol, also called a key agreement protocol, is the methodology by which various parties can exchange secret keys securely across an insecure network. It is therefore particularly relevant for people who decide to use symmetric cryptography. A key exchange protocol may well use some element of asymmetric cryptography for the exchange.

Key File
Key file only contains keys used for encryption. Some encryption programs store the encryption keys in a file where they can be conveniently accessed. Usually, the keys are themselves strongly encrypted, but you do not then need to enter each key as it is used. This helps ensure that if the key file is stolen, it will be of limited use to the attacker.

Key Fob
A key fob is a type of security token: a small hardware device with built-in authentication mechanisms. Just as the keys held on an ordinary real-world key chain or fob control access to the owner's home or car, the mechanisms in the key fob control access to network services and information.

Key generation functions
Key generation functions refer to a set of functions used by applications to generate and customize cryptographic keys. These functions include full support for changing chaining modes, initialization vectors, and other encryption features.

Key length
Key length refers to the values specified by some providers that indicate the length of the public/private key pairs and session keys used with that provider.

Key Logger
A keystroke logger, sometimes called a system monitor, is a hardware device or small program that monitors each keystroke a user types on a specific computer's keyboard. As a hardware device, a keystroke logger is a small battery-sized plug that serves as a connector between the user's keyboard and computer

Key Management
Key management is the administrative side of cryptography, and is one of the biggest problems faced by any crypto system. It involves the generation, certification, distribution and revocation of keys - all of which must be done in a secure manner. It can be undertaken manually, by software, or by outsourcing to a third party such as a Certification Authority.

Key Pair
A key pair is a set of mathematically related keys - typically the public and the associated private key in an asymmetric crypto system. The two keys are related in a way that makes it computationally infeasible to derive the private key from the public key.

Key Recovery
Key Recovery is a process for obtaining the value of a cryptographic key that previously was used to perform some cryptographic operation.

Key Retrieval
Key Retrieval is the generic name given to government's desire for the ability to decrypt intercepted messages. Since it is effectively impossible to decipher today's strong encryptions, governments are seeking to enforce their ability to retrieve cryptographic keys. It isn't ultimately important how this is achieved: it could be via mandatory key escrow or by hidden back doors - or by legislation such as the UK's RIP Act.

Key exchange
Key exchange refers to any method for sharing a secret key between two parties.

Key ring
Key ring is a data structure for storing public keys.

Key rollover
Key rollover refers to changing keys during a cryptographic communication session.

Key search attack
Key search attack refers to attempting to guess a cryptographic key.

Keyed Hash
Keyed Hash is a cryptographic hash function that requires both the message input and a secret key. This provides an additional level of security since a new hash result cannot be correctly calculated without knowledge of the secret key.

Keyed-hash message authentication code
Keyed-hash message authentication code, also known as hash-based message authentication code (HMAC), is a message authentication code (MAC) algorithm that combines a hashing algorithm with a secret key.

Keygen: Key Generator
Key generator(Keygen) is a small program that will generate a key or serial or registration number for a piece of software or cryptographic algorithms. Keygens are made available by software cracking groups for free download on various websites dedicated to software piracy.

Keyspace
Keyspace is the name given to the range of possible values for a cryptographic key. Normally described in terms of bits, as in the number of bits needed to count every distinct key. The longer the key length in bits, the greater the keyspace.

Keystroke Logger
A keystroke logger, sometimes called a system monitor, is a hardware device or small program that monitors each keystroke a user types on a specific computer's keyboard. As a hardware device, a keystroke logger is a small battery-sized plug that serves as a connector between the user's keyboard and computer.

Kilgetty
Kilgetty is a group of products designed by CESG to provide protection for UK government data stored on PCs. Kilgetty is a whole disk encryptor. It was developed following the theft of a laptop, containing the Allies' Gulf War Plans, at the height of the offensive. Kilgetty, and Kilgetty Plus, were designed by the CESG based at Cheltenham, and developed by Serco in Gloucester. The products have been certified for government use

Klaxon
Klaxon is a tool for detecting port-scanning attacks.

Klez Virus
Klez is the name of a family of viruses spreading through email systems such as Outlook.

Knark
Knark is a rootkit that targets the Linux platform.

Known plaintext attack
Known plaintext attack refers to a cryptanalytic attack in which the cracker has some plaintext/ciphertext pairs to work with.

KRI: Key Recovery Information
Key Recovery Information(KRI) means keys or other information provided to a Key Recovery Agent by a person, that can be used to decrypt that person's data and communications.

Kriz Virus
Discovered in the fall of 1999, the Kriz virus (known more formally as W32.Kriz, W32.Kriz.dr, or PE_KRIZ) infects files on Windows 9x and Windows NT and 2000 systems. It has a potentially devastating payload that triggers on December 25th of any year once an infected file is run. When this happens, the virus overwrites files on the floppy disk drive, hard drive, RAM drive, and network drives.

KryptoKnight
KryptoKnight is a cryptographic authentication system developed by IBM.

KSA: Key Scheduling Algorithm
In cryptography, the algorithm for computing the subkeys for each round in a product cipher from the encryption (or decryption) key is called the key schedule. Some ciphers have simple key schedules. For example, the block cipher TEA simply splits the 128-bit key into four 32-bit pieces and uses them repeatedly in successive rounds. RC5 and Blowfish have much more elaborate key-schedules.