Keychain

A keychain or key chain is a small chain, usually made from metal or plastic, that connects a small item to a keyring. The length of a keychain allows an item to be used more easily than if connected directly to a keyring. Some keychains allow one or both ends the ability to rotate, keeping the keychain from becoming twisted, while the item is being used. A keychain can also be a connecting link between a keyring and the belt of an individual. It is usually employed by personnel whose job demands frequent use of keys, such as a security guard, prison officer, janitor, or retail store manager. The chain is often retractable, and therefore may be a nylon rope, instead of an actual metal chain. The chain ensures that the keys remain attached to the individual using them, makes accidental loss less likely, and saves on wear and tear on the pockets of the user.

Spelling

Some spell checkers and dictionaries do not recognize the spelling "keychain," but separate the word into "key chain." Keychain collectors and many other people prefer to use it as a compound word ("keychain").

Keychain (software)

Keychain is password management system in OS X developed by Apple. It was introduced with Mac OS 8.6, and has been included in all subsequent versions of Mac OS, including OS X. A Keychain can contain various types of data: passwords (for websites, FTP servers, SSH accounts, network shares, wireless networks, groupware applications, encrypted disk images), private keys, certificates, and secure notes.

Storage and access

In Mac OS X, keychain files are stored in ~/Library/Keychains/, /Library/Keychains/, and /Network/Library/Keychains/, and the Keychain Access GUI application is located in the Utilities folder in the Applications folder. It is free, open source software released under the terms of the APSL. The command line equivalent of Keychain Access is /usr/bin/security.

The keychain file(s) stores a variety of data fields including a title, URL, notes and password. Only the passwords and Secure Notes are encrypted, with Triple DES.

Locking and unlocking

The default keychain file is the login keychain, typically unlocked on login by the user's login password, although the password for this keychain can instead be different from a user’s login password, adding security at the expense of some convenience. The Keychain Access application does not permit setting an empty password on a keychain.