information security
TRANSCRIPT
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Information Security
DR. HIMANSHU GUPTA, SENIOR FACULTY MEMBER, AMITY UNIVERSITY, NOIDA (INDIA)
What is a network?
A network consists of two or more devices that are linked in order to share resources or allow communications.
Can you think of various forms of a network?
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Computer Networks
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INTERNET
Downloadmusic
chat
Send in homework
Phone Networks
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Transmitter tower
call mum
Text messaging
businesscall
call friend
call friend
Transmitter tower
Text messaging
Text messaging
call daughter
businesscall
Satellite Networks
5Football game in Europe
Dish network
Watching the gameIn Bryan Texas, USA
What is Security?
Security is the act of protecting a person, property or organization from an attack.
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• Examples of attack on a person?
• Examples of attack on a property?
• Examples of attack on a organization?
Why do we need Information Security
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INTERNET
School Nurse
Name: ALICE JACKAddress: 1 BALL STRPhone Number: 888-9191DOB: 01/21/1993SSN: 999-111-2323Credit Card No:. 9988 5321Medical Records, Test scores
bad guy listens to the communication
sensitive data
Information Security Issues
Can you think of ways a bad guy can use the data he obtains to cause harm or attack?
Answer: Security Attacks
Can you think of what you can do to prevent a bad guy from having access to your private data or information?
Answer: Security Services 8
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Security Attacks
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Security Attacks
Informationsource
Informationdestination
Normal Flow
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Security Attacks
Informationsource
Informationdestination
Interruption
• Attack on availability
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Security Attacks
Informationsource
Informationdestination
Interception
• Attack on confidentiality
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Security Attacks
Informationsource
Informationdestination
Modification
• Attack on integrity
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Security Attacks
Informationsource
Informationdestination
Fabrication
• Attack on authenticity
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Classify Security Attacks
passive attacks - eavesdropping on, or monitoring of, transmissions to:
obtain message contents, ormonitor traffic flows
active attacks – modification of data stream to:masquerade of one entity as some otherreplay previous messagesmodify messages in transitdenial of service
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Security Attacks
Release of message contents
Trafficanalysis
• eavesdropping, monitoring transmissions
Passive threats
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Passive Attacks
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Security Attacks
Masquerade Denial ofservice
• some modification of the data stream
Active threats
Replay Modification of message contents
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Active Attacks
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Security Services
Confidentiality – protection from passive attacks
Authentication – you are who you say you are
Integrity – received as sent, no modifications, insertions, shuffling or replays
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Security Services
Nonrepudiation – can’t deny a message was sent or received
Access Control – ability to limit and control access to host systems and apps
Availability – attacks affecting loss or reduction on availability
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Network Security Model
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Cryptography
Cryptography -- from the Greek for “secret writing” -- is the mathematical “scrambling” of data so that only someone with the necessary key can “unscramble” it.
Cryptography allows secure transmission of private information over insecure channels (for example packet-switched networks).
Cryptography also allows secure storage of sensitive data on any computer.
CryptographyThe process of converting a message into a secret code called CIPHER TEXT, and changing the encoded message back to regular text called PLAIN TEXT.
(1) EncryptionThe conversion of the original message into a secret code or CIPHER TEXT using a key.
(2) DecryptionThe conversion of the encoded message or PLAIN TEXT back to the original message using the same key.
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Cryptography
Its All About Keys !!!
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My name is
Alice Jack.
Encryption
Plain text
Wi xkwo sc kvsmo tkmuWi xkwo sc kvsmo tkmu
key
My name is
Alice Jack.
Decryption
cypher text
Wi xkwo sc kvsmo tkmuWi xkwo sc kvsmo tkmu
key
Cryptography Wheel
You are meeting your friend for lunch at a restaurant. Which one? – it’s a secret!
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XA B
CD
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CIPHERTEXT PLAINTEXT
ENCRYPTIONKey = 4
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Golden Corral
Cryptography Wheel
Golden Corral
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XA B
CD
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CIPHERTEXT PLAINTEXT
ENCRYPTION
Key = 4
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A
B
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J I
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WV
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Jroghq Fruudo
DECRYPTION
Golden Corral
Cryptography Wheel
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XA B
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CIPHERTEXT PLAINTEXT
Key = 7
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ZYP
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I H
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UT
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Lyx Fivmnyl
DECRYPTION
Red Lobster
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The language of cryptography
symmetric key crypto: sender, receiver keys identical
public-key crypto: encryption key public, decryption key secret
(private)
plaintext plaintextciphertext
KA
encryptionalgorithm
decryption algorithm
KB
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Public-Private key Cryptography
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Secret/Symmetric-key Cryptography
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Secure Communication over Insecure Medium
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RSA Encryption Algorithm
For example. make p = 7and q = 13
We then calculate N = 7∗13 = 91 and (p−1)(q−1) = 72
We next select ke relatively prime to 72 and< 72, yielding 5
Finally,we calculate kd such that ke*kd mod 72 = 1, yielding 29
We how have our keys
Public key, ke, N = 5, 91
Private key, kd , N = 29, 91
Encrypting the message 69 with the public key results in the cyphertext 62
Cyphertext can be decoded with the private key
Public key can be distributed in cleartext to anyone who wants to communicate with holder of public key
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Encryption and Decryption using RSA Asymmetric Cryptography
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What is a Firewall?
a choke point of control and monitoring interconnects networks with differing trustimposes restrictions on network services
only authorized traffic is allowed
auditing and controlling accesscan implement alarms for abnormal behavior
is itself immune to penetrationprovides perimeter defence
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Firewall: Technical Concept
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Firewall Configurations
Secure Online Transaction Using Digital Signature
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Thank You!!!!
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Have A Nice Week!!!