1. XML, distributed data, replicated data, and Security

2. Database (relational) concepts
Database consistency
Key constraints (referential integrity)
Integrity constraints
Data dependencies
Normalization
Multi-user environment
Concurrency control
Locking protocols
Deadlock prevention/detection

3. Distributed Databases
Database fragmentation
Vertical
Horizontal
Commit protocols
Database replication
Mutual consistency
Pessimistic replica control
Optimistic replica control

4. Database Design Goal: Anomalies: Represent domain information
Avoid anomalies
Avoid redundancy
Anomalies:
Update: not all occurrences of a fact are changed
Deletion: valid fact is lost when tuple is deleted

5. Functional Dependencies
FD: X  A for relation R
X functional determines A, i.e., if any two tuples in R agree on attributes X, they must also agree on attribute A.
X: set of attributes
A: single attribute
If t1 and t2 are two tuples of r over R and t1[X]= t2[X] then t1[A]= t2[A]
What is the relation between functional dependencies and primary keys?

6. Example - FD Functional Dependencies: Name,Breed  Age
Weight
Date
Kennel
Pepper
G.S. 1 70
01/01/02
White Oak
Buddy
Mix 4 50
03/04/01
Little Creek
04/17/02
Panka
Vizsla 12 40
02/14/02
Functional Dependencies: Name,Breed  Age
Name,Breed  Weight

7. XML example
Reference paper
Figure 1
Figure 2
XML Keys
XML FDs

8. Normalization Functional Dependencies: Name,Breed  Age
Weight
Date
Kennel
Pepper
G.S. 1 70
01/01/02
White Oak
Buddy
Mix 4 50
03/04/01
Little Creek
04/17/02
Panka
Vizsla 12 40
02/14/02
Functional Dependencies: Name,Breed  Age
Name,Breed  Weight

9. Normalization Relation: primary keys FDs that violate BCNF
Decompose relation

10. Security Objectives Confidentiality Integrity Availability
Authenticity
Non-repudiation
Access Control Models

11. DB Access Control
Protection objects: system resources for which protection is desirable
Memory, file, directory, hardware resource, software resources, etc.
Subjects: active entities requesting accesses to resources
User, owner, program, etc.
Access mode: type of access
Read, write, execute

12. Relational

13. Secure XML Views - Example
medicalFiles
<medicalFiles> UC
<countyRec> S
<patient> S
<name>John Smith </name> UC
<phone> </phone> S
</patient>
<physician>Jim Dale </physician> UC
</countyRec>
<milBaseRec> TS
<name>Harry Green</name> UC
<phone> </phone> S
<physician>Joe White
</physician> UC
<milTag>MT78</milTag> TS
</milBaseRec>
</medicalFiles>
countyRec
milBaseRec
physician
Jim Dale
physician
Joe White
milTag
MT78
patient
patient
name
John Smith
phone
name
Harry Green
phone
View over UC data

14. Delete

15. XML Delete Operations Delete entire sub-tree under a deleted node
Most widely used approach
Problem: blind write
Delete only the viewable nodes
Problem: fragmentation of XML tree
Reject the delete
Problem: covert channel

16. Different Solution – Deleted Label
Basic Idea
A unique domain “Del” for deleted nodes
Change security classification of deleted node (o, {do  Del})
Perform after delete operation
Change security clearance of users, where s = (s, {ds}) > (o, {do}) to ( (s, {ds}) , (o, {do  Del}) )
Can be preprocessed
Use BLP axioms

17. Example - Top Secret View
Report
Title
Data
Date
Temperature
Images
Concrete Location
Defense Sector
(S,{Del}) TS P
Subject clearances:
(TS, {})  { (TS, {}) , (S, {Del}),
(P, {Del}) }
(S, {})  { (S, {}), (P, {Del}) }
(P, {})  { (P, {}) }

18. Attribute Association

19. Node Association - Example
MedicalDb
Patient *
Patient
Phone
Name
Patient
Birthdate
Race
Date
Diagnosis
Comments
Phone
Birthdate
Name
SSN
Race
Allergies
Allergen *
Date
Diagnosis
Physician
Prescription *
Comments
DTD of Patient Health Record

20. Layered Access Control
Object -
Association level
classification + -
Node level
classification

21. Updates Primary key: Person-name
What happens if the public user wants to insert a tuple <Dell, AT&T, $45,495>

22. Do we need anything else?
Security Objectives
Confidentiality
Integrity
Availability
Authenticity
Non-repudiation
Do we need anything else?