IN THIS CHAPTER
Understanding what the Mac OS X Keychain mechanism does
Learning the types of data you can store in a keychain
Dealing with alerts asking for keychain access
Using a keychain with Safari
Managing your keychains with the Keychain Access utility
To simplify the process of remembering and using passwords (along with other secure information), Mac OS X includes a system-wide mechanism known as the Keychain. The basic idea is that, as with a physical keychain, you can collect all your digital keys together in one place. All the information in your keychain is encrypted, and it can all be unlocked with a single password. As long as you can access your keychain, you can access all the individual keys (and the services they unlock).
If you see the word Keychain capitalized, it generally refers to Mac OS X's keychain management system as a whole — the Keychain, as opposed to individual keychains.
The Keychain uses 168-bit Triple DES (TDES) encryption to protect all its contents. Although TDES is an older standard, it has never been cracked and is generally considered secure for the foreseeable future.