Computer Security: CIA Triad and Kerberos Authentication

Desklib provides past papers and solved assignments for students. This report covers computer security.

Contents
Task No. 1..................................................................................................................................2
Task No. 2..................................................................................................................................3
Task No. 3..................................................................................................................................4
Task No. 4..................................................................................................................................5
Task No. 5..................................................................................................................................6
References..................................................................................................................................8
List of Figures
Figure 1: CIA design..................................................................................................................2
Figure 2: Kerberos Process........................................................................................................6

Task No. 1
Taking Computer Security in context, the CIA is extended as Confidentiality, Integrity, and
Availability. The main purpose of developing the CIA was to implement and evaluate
Computer Security. CIA has different requirements as well as the processes. Moving further,
explanation of the CIA is shown as-
Confidentiality:
The first part is the Confidentiality; Confidentiality is referred to as the personal data that
cannot be shared with any unauthorized person. So, here the data is completely kept
confidential in the system and can only be accessed by the Authorized person associated with
that data. This function makes sure that if the data is being read by the authorized person or
not. ACL that is extended as Access Control Lists helps in controlling the executions of the
user’s data. The main role in Confidentiality is of Cryptography.
Integrity:
The next part is the Integrity; it mainly helps in identifying the trustworthiness of the data
present in the System. Editing in the data can only be done by the user who has access to that
part of the Data. The editing can only be done by the permission of the accessed person. To
maintain the Integrity, several algorithms are used such as hashing, encryption, etc. Another
Factor in integrity is that it somewhere or the else depends on the Confidentiality function.
Availability:
The last part is the Availability, its role is to provide the required information when it is
needed and comes under the process of Availability. The function of Availability is to
provide the data to the authorized person when he/she requires it. For checking or assuring
that the data is present or available different methods named as optimizing the network,
maintenance of overall hardware and upgrading software are used. The above methods help
in stopping hackers from accessing the data.
Figure 1: CIA design
(Source: The Security Awareness Company, 2019)

Task No. 2
Talking about better security, the main focus is on the designing of the security.
For providing better security in the data or the system, designing is the main purpose that has
to be done. Few of the decisions of the security designs are explained below:
 The design that is being developed can be simple as well as complex. It mainly depends
on the system that is being used for it. Designing a simple design for the security is way
easy and better to use but on the other hand, it also benefits the hackers to hack the
system easily. If talking about the complex designs they are hard to use but also difficult
to get hacked.
 Controlling the data is the other factor that plays a main part in designing a system. The
main purpose of data controlling is to help in maintaining the integrity of the stored
information in the system. Various privileges are also being provided to the authorized
person in order to save the data from the hackers.
 Two controls are there at the start of the designing of the security. First is, where the
whole system is being controlled by the single point i.e. a centralization point is used to
control the whole system. Next is, where various points are used to control the system and
it is the decentralized control.
 Another one is the creation of the smaller privileged accounts in order to keep the
information safe, so there are no modifications done.
 The last one is the mechanism of the internal system, security mainly relies on it. If any
type of information gets leaked then attackers can easily attack and access the data.

Task No. 3
Calculation of the substitute values by using the S-Box table:
Substitution of seven
Firstly, Binary value is being found = 0111
First, 2 digits are then taken = 01 (Row Number)
Last 2 digits are then taken = 11 (Column Number)
Matching of the row, column numbers are done
In Binary, Substitution is = 1011
In Decimal, Substitution is = 11
Substitution of twelve
Firstly, Binary value is being found = 1100
First, 2 digits are then taken = 11 (Row Number)
Last 2 digits are then taken = 00 (Column Number)
Matching of the row, column numbers are done
In Binary, Substitution is = 0111
In Decimal, Substitution is = 7
Substitution of two
Firstly, Binary value is being found = 0010
First, 2 digits are then taken = 00 (Row Number)
Last 2 digits are then taken = 10 (Column Number)
Matching of the row, column numbers are done
In Binary, Substitution is = 1111
In Decimal, Substitution is = 15

Task No. 4
Calculations of the W[4], W[5], W[6] & W[7]
W[4]:
I = 4
RotWord = cf 4f 3c 09 (8 bytes permutation)
SubWord = 4 8a 84 eb 01 (Substitution is done)
W[i-Nk] = 2b 7c 15 16 (SubWord & Rcon XORed)
W[4] = a0 fa fe 17 (W[i-Nk] XORed with temp)
W[5]:
I = 5
Temp = W[4] = a0 fa fe 17
W[i-Nk] = 28 ae d2 a6
W[5] = 88 54 2c b1
W[6]:
I = 6
Temp = W[5] = 88 54 2c b1
W[i-Nk] = ab f7 15 88
W[6] = 23 a3 39 39
W[7]:
I = 7
Temp = W[6] = 23 a3 39 39
W[i-Nk] = 09 cf 4f 3c
W[7] = 2a 6c 76 05

Task No. 5
Understanding the Kerberos Systems and Kerberos Authentication Protocols
Kerberos is the name derived from a myth of ancient times which says that there was a guard
whose name was Kerberos who actually had three dog heads and having a tail that actually is
a snake. Kerberos is the Cryptography and it uses authorization to verify the users.
At present, the Kerberos system is the authorization tech that is used by Microsoft for its
Windows. It is also used in Apple OS, UNIX, and LINUX. Kerberos has provided really big
advancement for security purposes as well.
Kerberos also made a huge impact on the Internet as it helps in providing the secure as well
as the attractive work without any data leak.
Figure 2: Kerberos Process
(Source: SearchWindowsServer, 2019)
Steps that shows Kerberos Authentication Process:
 TGT is being requested by the user and the formation of KDC is done.
 KDC helps in verifying the Credentials of the User and sends back the encrypted TGT.
 TGT is being encrypted with the help of the TGS key.
 TGT then gets stored by the user and until the session expires, the manager does not
request for another TGT.
 The present TGT is then sent to the TGS with Service Principal Name of requested
service.
 Verification of the user’s TGT is done.
 Validation key is then sent to the user through TGS.

 At last for accessing the service requested, the validation session key is then forwarded by
the user to the server.

References
 The Security Awareness Company. (2019). The CIA Triad • The Security Awareness
Company. [online] Available at:
https://www.thesecurityawarenesscompany.com/2015/05/14/the-cia-triad/ [Accessed 4
Apr. 2019].
 SearchWindowsServer. (2019). Kerberos protocol: What every admin should know about
Windows authentication. [online] Available at:
https://searchwindowsserver.techtarget.com/tip/Kerberos-protocol-What-every-admin-
should-know-about-Windows-authentication [Accessed 4 Apr. 2019].