Page 315 - DCAP103_Principle of operating system

Principles of Operating Systems

Notes 7. .................... encryption technique works on the network layer.
8. A stored procedure is a precompiled sequence of .................... command in the database.

9. .................... mode adds a feedback mechanism to the encryption scheme.
10. A .................... is a part of computer system that is designated to block unauthorized access
while permitting authorized communications.

9.7 Summary

• CERT/CCC Current Activity KNOPPIX can also be used as a creative Linux system as
the educational CD, desktop, rescue system.

• Security systems generally implement a useful subset of a 3-dimentional matrix with
dimensions of actor, object, and action. Implementing the full matrix is never done for
both performance and usability reasons.
• Mainstream operating system security is primarily based on access control lists.
• Traditional UNIX access control is a type of discretionary ACL.
• The many possible actions are grouped into four categories—read, write, execute, and
special operations normally reserved for an object owner.
• Capabilities are unforgivable references to objects that let their holder access a well-defined
subset of operations defined on that object.
• Threats originated from viruses, which are strictly speaking programs that replicate
themselves without your knowledge.
• Secret key cryptography schemes are generally categorized as being either stream ciphers
or block ciphers.

• Database vendors release periodic security patches to fix several software bugs in the
database left open during development of the particular version.
• A firewall is a part of a computer system or network that is designed to block unauthorized
access while permitting authorized communications.
• It is a device or set of devices that is configured to permit or deny network transmissions
based upon a set of rules and other criteria.

9.8 Keywords

1. Domain Name System (DNS): The Domain Name System (DNS) is a hierarchical naming
system built on a distributed database for computers, services, or any resource connected
to the Internet or a private network.
2. Dynamic Host Configuration Protocol (DHCP): Dynamic host configuration protocol is
used to automatically assign TCP/IP addresses to clients along with the correct subnet
mask, default gateway, and DNS server.
Two ways for a computer to get its IP address:
• Using DHCP from a DHCP server.
• Manual configuration.

3. Encryption: The Encrypting File System (EFS) on Microsoft Windows is a file system filter
that provides filesystem-level encryption and was introduced in version 3.0 of NTFS. The

308 LOVELY PROFESSIONAL UNIVERSITY