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It’s not enough to have a secure connection between two machines. You also need to be sure that the person or computer you’re connected to is who it claims to be. This part discusses the pros and cons of the many available identification systems as well as ideal technology combinations.

Key Points

  • Philosophy tells us that a person is more than just the uniqueness of his or her body.
  • Technology views a person as a combination of attributes, knowledge, actions, and possessions.
  • A digital identity allows the defining characteristics of a person to be rapidly accessed whenever and wherever necessary.
  • When properly combined, multiple types of identification technology can improve security.


Modern identification systems use a combination of technologies, ranging from simple passwords to complex biometric systems (such as fingerprint or retina scanners). This part’s chapters explore the most commonly used identification technologies and concepts as follows:

  • Passwords examines the words, phrases, or patterns that grant access to a system.

  • Digital Certificates covers the electronic documents that verifiably prove the bearer’s identity.

  • Portable Identifiers discusses the physical items that can associate a digital identity with the bearer.

  • Biometrics concerns the technologies that measure a person’s vital statistics in order to determine identity.

  • Single Sign-On (web bonus) describes standards and technologies for providing a central repository of authentication information. (Online Bonus Content)