ABSTRACT
This chapter is adapted from [64] to suit this text. The following describes mechanisms for securely logging in to a computer.
▼ Login Security To login (also called signing in) to a computer, we must provide a passphrase,
which may be as simple as a single word, called a password, or a sequence of words used to identify us uniquely for secure access to the system. The encrypted passphrase will be accompanied by our plaintext username ID. A user ID, authenticated by its associated passphrase, determines the privileges allotted to the user, which may vary from personal e-mail access to superuser status, where actions may be executed that are protected by the operating system.
