C - D
A cache can be thought of as a temporary storage area used by a system to speed up processing of commonly data. In the information security realm, the term is most often used in reference to temporary data used by internet browsers to speed up page load times. Different types of malware, spyware, and adware often disguise themselves as cache in an attempt to embed themselves into a system.
Like cache, a cookie is a file stored on your system as a means of helping an internet browser run more efficiently. Cookies often store data such as usernames and preferences so that these do not have to be re-entered every time a particular page is visited.
This is a slang term that is mostly synonymous with the term breach. To crack a system means to break past the security and gain access to the PC.
The meaning of this term in the information security realm is parallel to its meaning in common usage. Credentials are a way of providing a system with identification so that it knows you are an authorized user (i.e. username and password).
Decryption is the process of converting encrypted data back into its original form. Encrypted data (see Part 3 of this series) is data that has been altered in such a way as to "disguise" its true content or meaning for added security.
Denial of Service Attack
A DoS attack is a method of overloading a network with connection requests to the point that it cannot function normally. The purpose is to cripple a system so that other processes are halted and other users are prevented from accessing the system or using its resources.
This is a term borrowed from the military which means demilitarized zone. Essentially this is an isolated section of a network that is neither part of the private business network or the public internet. A DMZ is often used for housing web and email servers for customer servicing and contact. It is a neutral area that protects the actual business network from the public but still allows the business to interact with and service customers in the public internet domain.