# 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 SecuritySystem Security
Protection of data on systemProtection of computer system
Prevents corruption, unauthorized usePrevents viruses, hacking
Example: encryptionExample: firewall, passwords
--- ## 6.2 DATA INTEGRITY ### 6.2.1 Data Validation **Definition:** Checks if data entered is valid (sensible). **Methods:**
MethodDescription
**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:**
MethodDescription
**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