Identification is the process by which a subject professes an identity and accountability is initiated. A user providing a username, a logon ID, a personal identification number (PIN), or a smart card represents the identification process. Providing a process ID number also represents the identification process. Once a subject has identified itself, the identity is accountable for any further actions by that subject. Information technology (IT) systems track activity by identities, not by the subjects themselves. A computer doesn’t know one human from another, but it does know that your user account is different from all other user accounts.