Computer Science Test 3 Nddc Scholarship

Effective antivirus protection requires a three-tier approach: the software must be installed on the system, it must be actively running in the background to provide real-time scanning, and it must be regularly updated with the latest virus definitions. If any of these conditions are not met, the computer remains highly vulnerable to newly released malware threats.

Clear text (or plaintext) refers to data that has not been subjected to cryptographic transformation. If clear text is intercepted during transmission over a network (for example, through packet sniffing), it can be easily read and understood by unauthorized parties, which is why sensitive information like passwords should always be encrypted.

A Discretionary Access Control List (DACL) is an internal list attached to an object (like a file or folder) in an operating system. It specifies which users or system processes are granted or denied access to that specific object. It is 'discretionary' because the owner of the object has the authority to control who has permission to access it.

Phishing emails often contain spelling mistakes and use generic greetings like 'Dear Customer' because they are mass-sent to thousands of people. Legitimate organizations, such as banks or government agencies, typically use your actual name and maintain professional standards in their communication. Checking both of these factors is a standard way to identify fraudulent messages.

Packet sniffing involves using a software tool or hardware device to intercept and log traffic passing over a digital network. While network administrators use it for troubleshooting and legitimate monitoring, hackers use it maliciously to capture unencrypted data, such as usernames and passwords, as they are transmitted in 'clear text' between computers.

Network Address Translation (NAT) is a method used by routers to map multiple private IP addresses within a local network to a single public IP address. This provides a layer of security by hiding the internal IP addresses of individual computers from the public internet, making it significantly harder for external hackers to target specific machines directly.

A cipher is a mathematical method or set of rules used to transform readable information (plaintext) into an unreadable format (ciphertext). Historically, ciphers like the Caesar cipher were simple letter substitutions, but modern digital ciphers use complex bitwise operations and large numerical keys to ensure that data remains secure and private during transmission or storage.

A network protocol defines the digital 'handshake' and data formatting rules that computers must follow to exchange information. Without these standardized rules—such as HTTP for web browsing or SMTP for email—different hardware and software from various manufacturers would be unable to understand the data packets being sent between them.

A Trojan horse relies on social engineering to trick a user into executing it. Unlike a virus or worm, it does not self-replicate. Once a user installs the 'useful' program, the Trojan can perform various malicious acts, such as stealing passwords, deleting files, or opening a 'backdoor' that allows a hacker to take remote control of the system.

Ethical issues in computing deal with the right and wrong ways to use technology. This includes respecting user privacy, avoiding software piracy, and ensuring data accuracy. Professional bodies often establish codes of ethics to guide IT specialists in making decisions that protect both individuals and the integrity of the digital infrastructure.