CertiGuide to Security+  9  Chapter 1:  General Security Concepts (Domain 1.0; 30%)       9  1.2  Authentication

1.2.2  Challenge Handshake Authentication Protocol (CHAP) 1 1.2.4  Username/Password

The “bottom line” goal of certificates is to establish trust among clients, so that repeatedly providing a password to authenticate oneself is not required, and so that a communication partner may have greater certainty that the person on the other side of the conversation really is who they say they are. Certificates are generally issued by a Certificate Server. By using key information distributed in certificates, a user can:

• Encrypt a message (Privacy)
  
  
• Confirm a message was not modified (Integrity)
  
  
• Confirm the sender identity (non-repudiation)

Not all certificates are valid for all uses. For example, if the organization issuing the certificate did not carefully verify someone’s identity before issuing them a certificate, it might not be wise to rely on the identifying information in it. Frequently these certificates are called digital certificates. Refer to sections 4.3.1 and 5.5.2 for more information. Certificates are discussed in greater detail on the section on public key infrastructure.

1.2.2  Challenge Handshake Authentication Protocol (CHAP) 1 1.2.4  Username/Password