Basics of cyber security essentials with the introduction to cipher and its types

1. UNIT – I
CYBER SECURITY FUNDAMENTALS
(Part –I)
Dr.M.Karthika
Head/Department of InformationTechnology,
MTNC,Madurai.

2. NETWORK AND SECURITY CONCEPTS
 Information Assurance Fundamentals
 Authentication
 Authorization
 Non repudiation
 Confidentiality
 Integrity
 Availability

3. INFORMATION ASSURANCE FUNDAMENTALS
 Authentication, authorization, and non repudiation
are tools that system designers to maintain system
security with respect to Confidentiality, Integrity and
availability.
 National Information Assurance Glossary (NIAG)
published by the U.S. Committee on National Security
Systems.

4. AUTHENTICATION
 Authentication is important to any secure
system.
 The key to verifying the source of a message or
that an individual is whom he or she claims.
 The NIAG defines authentication
“security measure designed to establish the
validity of a transmission, message, or originator,
or a means of verifying an individual’s
authorization to receive specific categories of
information.”

5. FACTORS OF AUTHENTICATION
FACTOR EXAMPLES
Something
You Know
Information the system assumes others do not know;
this information may be secret, like a password or PIN
code, or simply a piece of information that most
people do not know, such as a user’s mother’s maiden
name.
Something
You Have
Something the user possesses that only he or she
holds; a Radio Frequency ID (RFID) badge, One-Time-
Password (OTP) generating Token, or a physical key
Something
You Are
A person’s fingerprint, voice print, or retinal scan—
factors known as biometrics

6. FACTORS OF AUTHENTICATION

7. AUTHORIZATION
 Authorization focuses on determining what a user has permission to do.
 NIAG defines authorization as
“access privileges granted to a user, program, or process.”
 Example:
1. An online banking application will authenticate a user based on his or
her credentials .
2. It must then determine the accounts to which that user has access.
3. The system determines what actions the user can take regarding those
accounts.

8. NON REPUDIATION
 The NIAG defines as
“assurance the sender of data is provided with proof of delivery
and the recipient is provided with proof of the sender’s identity, so neither
can later deny having processed the data.”
 The world of digital communications, no notary can stamp each
transmitted message, but non repudiation is still necessary.
 Secure systems normally rely on asymmetric (or public key) cryptography.
 These systems use one key (private) for signing data and use the other key
(public) for verifying data.
 Asymmetric key systems have the non repudiation property .
Example

9. CIA TRIAD

10. CONFIDENTIALITY
 The concept of confidentiality primarily focuses on
concealing or protecting the information.
 The NIAG defines confidentiality as
“assurance that information is not disclosed to
unauthorized individuals, processes, or devices.”
 One way to protect information is by storing it in a
private location or on a private network that is limited
to those who have legitimate access to the information.
 Assuring that unauthorized parties do not have access
to a piece of information is a complex task.

11. Step :1 The information must have protections
capable of preventing some users from
accessing it.
Step : 2 Limitations must be in place to restrict
access to the information to only those who
have the authorization to view it.
Step :3 An authentication system must be in
place to verify the identity of those with access
to the data.
Three major steps

12. INTEGRITY
 Data integrity, or ensuring that stored data are
accurate and contain no unauthorized
modifications.
 NIAG defines integrity as
Quality of an IS (Information System) reflecting
the logical correctness and reliability of the operating
system

13.  Authentication, authorization, and non repudiation as the
keys to maintaining integrity, is preventing those without
authorization from modifying data.
 Software flaws and vulnerabilities can lead to accidental
losses
in data integrity and can open a system to unauthorized
modification
 Disrupting the integrity of data at rest or in a message in
transit can have serious consequences.
 Ensuring the integrity of this type of message is vital to any
secure system
LOSSES IN INTEGRITY

14. AVAILABILITY
 Information systems must be accessible to users for
these systems to provide any value.
 If a system is down or responding too slowly, it
cannot provide the service it should.
 The NIAG defines availability as
“timely, reliable access to data and information
services for authorized users.”
 Attacks on availability are somewhat different from
those on integrity and confidentiality.

15. DENIAL OF SERVICE (DOS) ATTACK
 The best-known attack on availability is a denial of service (D o S)
attack.
•Resources in question may be memory, CPU
time, network bandwidth, and/or any other
component that an attacker can influence.
Resource
Exhaustion
• The attacker sends so much network traffic
to the targeted system that the traffic
saturates the network and no legitimate
request can get through.
Network
Flooding

16. BASIC CRYPTOGRAPHY
 The English word cryptography derives from Greek and translates
roughly to “hidden writing.”
 The ancient Egyptians began the first known practice of writing
secret messages, using nonstandard hieroglyphs to convey secret
messages as early as 1900 BC.
 Methods of hiding the content of a message-known as ciphers.

17.  Cipher is a frequently used algorithm in cryptology.
 It is a method of encrypting and decrypting data.
CIPHER
Two Basic
Transformation
Transposition Ciphers
Maintain all of the
original bits of data in
a byte but reverse their
order.
Substitution Ciphers
Substitute specified data
sequences with alternative
data sequences.
The data generated by any method is known as the ciphertext.

18. HOW DOES A CIPHER WORK?
An encryption technique is used by ciphers to convert
plaintext, which is a legible communication, into ciphertext,
which seems to be a random string of letters.

19. TYPES OF CIPHERS

20. SUBSTITUTION CIPHERS
 As name implies the current letter, character,
alphabet, number, bit is replaced by some other
letter, character, alphabet, number, bit as well.
 The replacement maybe applied on a single character
or a block of characters.

21. 1. MONOALPHABETIC CIPHER
 Single character is replaced with single alternate
character throughout the whole data set. For example, if
for a particular data set A is considered as H, then at
everyplace letter A is used, that will be replaced with H.
 This is an easy method but to find the key is very difficult
so this is a good cipher.
Example:
Plain text: Cipher is an algorithm.
Cipher
text: PVCUREVFNANYTBEVGUZ.

22. 2. POLYALPHABETIC CIPHER
• In this table multiple alternates are existing for single character.
• The final alternate is depending on the character and the keyword to
encrypt the text.
• For transformation a key is also used and this key is different for
each dataset.
For example, take a plain text APPLE and the keyword is RIGHT
A = R
P = I
P = G
L = H
E =T

23. 3. CAESAR CIPHER
 This is very simple.
 In this each alphabet is replaced with its upcoming third
subsequent alphabet.
 Example: A is replaced by D, B is replaced by E etc.
let’s transform word Cipher:
C = F
I = L
P = S
H = K
E = H
R = U
So, Cipher is transformed in FLSKHU.

24. 4. PLAYFAIR CIPHER
 In this a Playfair square is used, which is 5 X 5 in
size.
 Steps are as follows:
 First choose a keyword of your own choice. For example,
choose “cipherincryptography” (cipher in cryptography)
 Now enter the characters in the 5 X 5 matrix.
 Avoid the repeated word.
 Fill I and J in one cell.
A B C D E F G H I J K L M N O P Q R S T U V W X Y
Z
For example, choose word Apple:
Apple = AP PL EZ
AP = BI (We can choose any either I or J)
PL = IM
EZ = OE
So, Apple is encrypted as BIIMOE.

25. 5. HILL CIPHER
 Choose a key matrix (m*n) size.
 Then choose the word to encrypt.
 Break the word in size equal to key matrix.
 Now convert the word matrix in number matrix.
 Now find the cipher matrix by using this formula:
C = KP mod 26
Here C = cipher matrix
K = key matrix.
P = word matrix
now transform the cipher matrix into word matrix.
Follow the process for the whole data set.

26. PATH TO CRYPTOGRAPHY
 A Lottery Cage - Randomize number Selection
Clear T h e a c T s t a r t s a t m i d n i g h t
Cage 22 19 2 11 5 12 19 5 16 12 6 11 5 2 19 15 24 20 18 2 21 6 5 19 17 21
Cipher O g k f o L e h e g b y u s p q t d k y t n z y n

27. THE GERMAN ENIGMA CODING
MACHINE

28. THANKYOU