CHAPTER 6: SECURITY, PRIVACY AND DATA INTEGRITY

6.1 DATA SECURITY 

 6.1.1 Definitions 

 Data Security: 

 

 Ensuring data is protected against loss and unauthorized access 

 Protection of data on computer system 

 

 Data Integrity: 

 

 Ensuring data is valid and does not corrupt after transmission 

 Data is accurate and reliable 

 

 Data Privacy: 

 

 Ability to determine what data is shared with third party 

 

 6.1.2 Threats to Computer and Data Security 

 Malware: 

 

 Software designed to damage computer or network 

 Virus:  Replicates by inserting copy into other software; can crash computer, delete/corrupt data 

 Spyware:  Gathers information about users' activity; monitors online/offline behaviour 

 

 Hacking: 

 

 Illegal access to computer system 

 Obtain confidential data 

 Can cause identity theft 

 Can delete/corrupt data 

 

 Phishing: 

 

 Emails attempting to obtain confidential data 

 Impersonates legitimate organizations 

 Causes identity theft 

 

 Pharming: 

 

 Redirects users to fake websites 

 Appears legitimate 

 Gains confidential data 

 

 6.1.3 Security Measures 

 User Accounts and Passwords: 

 

 Deny unauthorized access 

 User-assigned privilege levels 

 File access permissions 

 

 Firewalls: 

 

 Filters information between computer and internet 

 Detects illegal connection attempts 

 Blocks unauthorized access 

 

 Authentication: 

 

 Determines if someone is who they claim 

 Methods: passwords, digital signatures, biometric scans 

 

 Anti-virus Software: 

 

 Detects and removes viruses 

 Checks files for malicious patterns 

 Runs in background 

 

 Anti-spyware Software: 

 

 Detects and removes spyware 

 

 Encryption: 

 

 Converts data to code 

 Doesn't stop access but makes data meaningless 

 Requires decryption to read 

 

 Data Backup: 

 

 Exact copy of original data 

 Stored at different location 

 Disk-mirroring: writes to multiple disks simultaneously 

 

 6.1.4 Data Security vs System Security 

 

 

 

 

 Data Security 

 System Security 

 

 

 

 

 Protection of data on system 

 Protection of computer system 

 

 

 Prevents corruption, unauthorized use 

 Prevents viruses, hacking 

 

 

 Example: encryption 

 Example: firewall, passwords 

 

 

 

 

 

 

 6.2 DATA INTEGRITY 

 6.2.1 Data Validation 

 Definition: Checks if data entered is valid (sensible). 

 Methods: 

 

 

 

 

 Method 

 Description 

 

 

 

 

 Range Check 

 Data must be between set values 

 

 

 Format Check 

 Data must follow correct pattern 

 

 

 Length Check 

 Data must have exact number of characters 

 

 

 Presence Check 

 Checks if data has been entered 

 

 

 Existence Check 

 Data entered must exist in database 

 

 

 Limit Check 

 Value within acceptable min/max 

 

 

 Check Digit 

 Arithmetic result of other digits; verifies accuracy 

 

 

 

 

 

 6.2.2 Data Verification 

 Definition: Checks data entered is accurate (correct). 

 Data Entry Verification: 

 

 

 

 

 Method 

 Description 

 

 

 

 

 Visual Check 

 Person manually compares original with entered data 

 

 

 Double Entry 

 Enter data twice; compares results 

 

 

 

 

 

 Data Transfer Verification: 

 Parity Check: 

 

 Number of 1s in byte must be odd or even 

 If parity doesn't match, error detected 

 Limitation: Cannot detect 2-bit transposition 

 

 Checksum Check: 

 

 Data sent as block of bytes 

 All bytes added together 

 Checksum calculated before and after transmission 

 If different, error occurred; block must be resent