Intro Computer Security Systems

Chapter 1

Information System

A combination of hardware, software, data, networks, and users. (Ex: A college system)

Cyberspace

Virtual environment created by digital networks (social media, e-commerce)

Cryptography

Technique used to secure data from unauthorized users

Encryption

converts readable data (cleartext) into unreadable format

Ciphertext

the scrambled, protected data after encryption

Uptime

System operational time (Ex: A web server runs for 720 hours)

Downtime

System unavailable (Ex: 6 hours of inaccessibility)

Availability

total uptime / (total uptime + total downtime) (Ex: 720 / (720 + 6) = 99.18%

MTTF

Average time a system runs before failure (Ex: 3 failures over 720 hours. 720 / 3 = 240 hours)

What does MTTF mean?

Mean Time to Failure

What does MTTR mean?

Mean Time to Repair

MTTR (Mean Time to Repair)

Average repair time (Ex: total repair time 6 hours / 3 failures —> 2 hours)

What does MTBF mean?

Mean Time Between Failures

MTBF (Mean Time Between Failures)

(MTTF) Mean Time to Failures + (MTTR) Mean Time to Repair

What does RPO mean?

Recovery Point Objective

RPO (Recovery Point Objective)

Maximum acceptable data loss (Ex: 1 Hour —> backups every hour)

What does RTO mean?

Recovery Time Objective

RTO (Recovery Time Objective)

Maximum acceptable downtime (Ex: 2 hours —> system must be restored within 2 hours

Seven Domains of IT infrastructure

User, Workstation, LAN, LAN-to-WAN, WAN, Remote Access, Systems/Application