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Learn about computer-based and non-computer-based controls, encryption, decryption, firewalls, web security, and handling challenges over the internet. Protect your database against theft, fraud, and privacy breaches with effective countermeasures.
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Chapter 19 Security
Agenda • Database Security • Countermeasure • Computer-based • Non-computer-based • Challenge over the Internet • Firewall • Web security
Database Security • Definition • Mechanisms to protect the database against intentional or accidental threats • Asset • Hardware • Software • Communication network • Database • Individual (user, programmer, operator, administrator, and outsider) • Threat • Theft and fraud • Consequence • Loss of confidentiality • Loss of privacy • Loss of integrity • Loss of availability
Countermeasures • Computer-based controls • Non-computer-based controls
Computer-based Controls - 1 • Authorization & authentication • Password and account number • Discretionary access control (grant and revoke) • Mandatory access control (object, security class, and clearance) • Virtual views
Computer-based Controls - 2 • Logs or journaling • Transaction log • Violation log • Check points • Integrity • Domain • Enterprise • Entity • Referential • Backup (redundant array of independent disks - RAID) & recovery • Audit
Computer-based Controls - 3 • Encryption or cryptosystem • Encryption key • Encryption algorithm • Decryption key • Decryption algorithm • Symmetric encryption (Data Encryption Standard (DES) • Asymmetric encryption (RSA)
Example of Encryption - I • Divide text into groups of 8 characters. Pad with blank at end as necessary • Select an 8-characters key • Rearrange text by interchanging adjacent characters • Translate each character into an ordinal number with blank as 0, A as 1, B as 2… • Add the ordinal number of the key to the results • Divide the total by 27 and retain the remainder • Translate the remainder back into a character to yield the cipher text
Example of Encryption - II • Message: DATA COM • Key: PROTOCOL • A D A T C M O (switching) • 01 04 01 20 03 00 13 15 (adatc mo) • 16 18 15 20 15 03 15 12 (protocol) • 17 22 16 40 18 03 28 27 (sum) • 17 22 16 13 18 03 01 00 remainder • Q V P M R C A SPACE
Example of Decryption - I • Divide cipher text into groups of eight characters. Pad with blanks at end as necessary • Translate each cipher text alphabetic character and the encryption key into an ordinal number • For each group, subtract the ordinal number of the key value from the ordinal number of the cipher text • Add 27 to any negative number • Translate the number back to alphabetic equivalents • Rearrange the text by interchanging adjacent characters
Example of Decryption - II • Q V P M R C A SPACE • 17 22 16 13 18 03 01 00 (qvpmrca ) • 16 18 15 20 15 03 15 12 (protocol) • 01 04 01 -7 03 00 -14 -12 (substract) • plus 27 27 27 27 • 01 04 01 20 03 00 13 15 • A D A T C M O • D A T A C O M
Non-Computer-based Controls • Security policy • Contingency plan • Person, phone no., procedures • Site (cold, warm, or hot) • Personnel control • Reference • Termination • Training • Balance of duty • Escrow & maintenance agreements • Physical
Challenge over the Internet • Privacy (inaccessible except sender & receiver) • Integrity (no change during transmission) • Authenticity (genuine sender) • Non-fabrication (genuine receiver) • Non-repudiation (sender can not deny)
Firewall • Definition • A system to prevent unauthorized access to or from a private network • Types • Packet filter (difficult to configure and subject to IP spoofing) • Application gateway (degrade performance) • Circuit level gateway (TCP or User Datagram Protocol UDP) • Proxy server (performance & filtering)
Web Security • Message digest algorithms and digital signature • Digital signatures & Certificate Authority (CA) • Kerberos: centralized security server (certificate server • Secure Sockets Layer (SSL) for data & Secure HTTP (S-HTTP) for individual message • Secure Electronic Transaction (SET) for credit card & Secure Transaction Technology (STT) for bank payment
Points to Remember • Database Security • Countermeasure • Computer-based • Non-computer-based • Challenge over the Internet • Firewall • Web security
Assignment • Review chapters 5-6, 11-14, 19 • Read chapter 20 • Exam 3 • Date: • Project • Normalization and Corrected EER diagram due date: • SQL, corrected normalization, and EER diagram due date: