Database Security and analyzing information

Security
• Data security defines the prevention of data
corruption through the use of controlled access mechanisms.
• Data security deals with the protection of data
• Data security is making sure only the people who should have
access to the data are the only ones who can access the data.
• Data security refers to making sure that data is accessed by its
intended users, thus ensuring the privacy and protection of
data.
• Authentication/authorization, encryptions, and
masking are some of the popular means of data security.

 Security
3

Violation

Levels

Authorization

Views

Encryption

Violation
4
 Malicious
 Unauthorized reading of data
 Unauthorized modification
 Unauthorized destruction
 Accidental
 Crashes
 Concurrent access anomalies
 Violation of database consistency constraints.

5
Security
 Database system level

Authentication and authorization mechanisms to allow
specific users access only to required data

We concentrate on authorization in the first part of this
session
 Operating system level

Operating system super-users can do anything they want
to the database!

5
Security
 Network level: must use encryption to prevent

Eavesdropping (unauthorized reading of messages)

An eavesdropping attack occurs when a hacker deletes and
modifies data that is transmitted between to devecies.

Masquerading (pretending to be an authorized user or

That attack uses a fake identity to gain unauthried access to
personal access identification.
sending messages supposedly from authorized
users)

Security (Cont...)
7
 Physical level

Physical access to computers allows destruction
of data by intruders;

Traditional lock-and-key security is needed

Computers must also be protected from floods,
fire, etc.


Security (Cont...)
8
Human level

Users must be screened to ensure that authorized users
do not give access to intruders

Users should be trained on password selection and
secrecy.


Authorization
9
Forms of authorization on parts of the database:
 Read authorization - allows reading, but not
modification of data.
 Insert authorization - allows insertion of new data, but
not modification of existing data.
 Update authorization - allows modification, but not
deletion of data.
 Delete authorization - allows deletion of data

Views
10
 Users can be given permission on views, without being given
any permission on the base table used in the view definition.
 Ability of views to hide data serves both to simplify usage of
the system and to enhance security by allowing users access
only to data they need for their job.
 A combination of relational-level security and view- level
security can be used to limit a user’s access to precisely the
data that user needs.

View
Example
11
 Suppose a bank clerk needs to know the names
of the customers of each branch, but is not
authorized to see specific loan information.

Approach: Deny direct access to the loan base table ,
but grant access to the view cust-loan, which consists
only of the names of customers and the branches at
which they have a loan.

View Example (Cont.)
12
The cust-loan view is defined in SQL as follows:
create view cust-loan as
select branchname, customer-name
borrower, loan
where borrower.loan-number =
loan.loan- number
 The clerk is authorized to see the result of
the query:
select * from cust-loan

Role Security Specification in
SQL
13
 A database role is a collection of any number of privilieges/
permissions that can be assigned to one or more user.
 Database role also is also given name for that collection of
privileges.
 The majority of today’s RDBMS’s come with predefined roles
that can be assigned to any user.

Role Security Specification in
SQL
14

Delegation of granting
privilege
15
 with grant option: allows a user who is granted a
privilege to pass the privilege on to other users.

Example:
grant select on branch to U1 with grant option gives U1
the select privileges on branch and allows U1 to
grant ‘select’ privilege to others U1 can
give command
Grant select on branch to U2

Revoking
Authorization
16
 The revoke statement is used to
revoke authorization.
Revoke select on tblstudent from hamid;
 Revocation of a privilege from a user may cause
other users also to lose that privilege;
 We can prevent cascading by specifying rest rict:
 revoke select on branch from U1, U2, U3 restrict

Encryption
17
 Data may be encrypted when database
authorization provisions do not offer sufficient
protection.
 Properties of good encryption technique:
 Relatively simple for authorized users to
encrypt and decrypt data.
 Extremely difficult for an intruder to determine
the encryption key.

To ensure integrity of
database
18
Define
 Entity constraints (Primary
key constraint)
 Domain constraints
 Referential integrity
 Triggers

Entity Constraints
19
 Entity integrity enforcement guarantees that
each row in a table is uniquely identified by
non-null values contained in its primary key
columns.
 Integrity constraints guard against accidental
damage to the database, by ensuring that
authorised changes to the database do not
result in the loss of data consistency.

Domain constraints
20
 Domain constraints are most
elementary form of integrity
constraints.
 They test values inserted in the
database
 Examples
 On insertion of item into order_item table
the quantity must be greater that 0.
 On update the new salary must be greater
than old salary.
 On insertion a new employee into EMP

Referential Integrity in
SQL
21
(Cont…)
Example
 Create table account
(AccountNo char(10)
not null, BranchName
char(15), balance integer,
primary key(AccountNo)
foreign key(BranchName)
references branch)

Trigger
22
 A Trigger is statement that is executed
automatically by the system as a side
effect of a modification to the database.
 To design a trigger mechanism, we must
specify the condition under which trigger
is to be executed and action to be taken.

Database Security and analyzing information

More Related Content

Similar to Database Security and analyzing information

More from muhammadFaheem656405

Recently uploaded

Database Security and analyzing information