Chapter 19 Security

Agenda Database Security Countermeasure Challenge over the Internet Computer-based Non-computer-based Challenge over the Internet Firewall Web security

Database Security Definition Asset Threat Consequence 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 Types 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: