Exam Essentials

Be able to describe the process of a hashing algorithm. Hashing algorithms are used to mathematically derive a key from a message. The most common hashing standards for cryptographic applications are the SHA and MD algorithms.

Be able to describe the principles of a symmetric algorithm. A symmetric algorithm requires that receivers of the message use the same key. This key is called a private key. Symmetric algorithms can be extremely secure. This method is widely implemented in governmental applications. The private key is changed using out-of-band transmission.

Be able to describe the process of asymmetric algorithms. Asymmetric algorithms use a two-key method of encryption. The message is encrypted using the private key and decrypted using a second key or public key. The key is derived from the same algorithm.

Be able to describe the primary objectives for using cryptographic systems. The main objectives for these systems are confidentiality, integrity, authentication, and non-repudiation. Digital signatures can be used to verify the integrity and provide non-repudiation of a message.

Be able to describe the process used in PKI. PKI is an encryption system that utilizes a variety of technologies to provide confidentiality, integrity, authentication, and non-repudiation. PKI uses certificates issued from a CA to provide this capability as well as encryption. PKI is being widely implemented in organizations worldwide.

Be able to describe the revocation process in PKI. PKI issues a CRL from a CA when a revocation request is made. This CRL can take anywhere from a few hours to several days to propagate through a community. OCSP is a protocol that can be used to provide immediate validation of a certificate.

Be able to describe the trust models used in PKI. PKI provides the ability for hierarchical, bridged, meshed, and hybrid models for trust. A CA tree is broken down into subcomponents. These subcomponents are called root authorities, intermediate CAs, and leaf CAs.

Be able to describe the primary attack methods used against cryptographic systems. The primary attacks against cryptographic systems involve birthday attacks, mathematical attacks, and weak key attacks.