Security, Privacy and Data Integrity

• Data security protects data from loss, damage or unauthorised access; data privacy keeps personal data confidential; data integrity means data is accurate, consistent and up to date.
• Both the data and the computer system itself must be secured.
• Security measures: user accounts, passwords, authentication (digital signatures, biometrics), firewall, anti-virus, anti-spyware, encryption.
• Threats: malware (viruses, spyware), hackers, phishing, pharming, and how to reduce each risk.
• Validation checks data is reasonable: range, format, length, presence, existence, limit and check digit.
• Verification checks data has been entered or transferred accurately: visual check, double entry, parity (byte and block), checksum.

Three different ideas

Data security: keeping data safe from loss, corruption or unauthorised access (back-ups, passwords, encryption). Data privacy: the right of individuals to keep their personal data confidential, so only authorised people see it, as required by data protection laws. Data integrity: the data is accurate, complete and consistent, and stays that way when stored, processed or transferred.

Both the data and the computer system need protecting. If the system is attacked or fails, the data may be stolen, changed or lost, and the organisation cannot operate; if the data is stolen it may be misused even though the system still works.

Protecting a stand-alone PC up to a network

• User accounts: each user logs in separately, so access rights can be set per user and activity can be logged.
• Passwords: must be strong (long, mixed characters), changed when compromised, not reused; accounts locked after several failed attempts.
• Authentication: proving identity. Biometrics (fingerprint, face, iris) are unique to a person and cannot be forgotten. A digital signature is created with the sender’s private key; the receiver checks it with the sender’s public key, which proves who sent a message and that it was not changed. Two-factor authentication combines two methods.
• Firewall (hardware or software): sits between a computer or network and the internet; checks incoming and outgoing traffic against rules (allowed IP addresses, ports, applications) and blocks traffic that breaks them.
• Anti-virus software: scans for known virus signatures and suspicious behaviour, quarantines or deletes infected files.
• Anti-spyware: detects and removes spyware, and blocks programs that try to record or send data secretly.
• Encryption: scrambles data with a key so it is unreadable without the decryption key. It does not stop data being intercepted, but makes intercepted data useless.