Keychain (Mac OS)
Keychain is Apple Inc.'s password management system in Mac OS. It was introduced with Mac OS 8.6, and has been included in all subsequent versions of Mac OS, including Mac 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.
Read more about Keychain (Mac OS): Storage and Access, Locking and Unlocking, Password Synchronization, History