This document discusses network security and cryptography. It begins by defining network security principles like confidentiality, integrity and availability. It then describes common network security attacks such as man-in-the-middle attacks, denial-of-service attacks, password attacks and social engineering. The document introduces cryptography as a way to provide secure communications and explains cryptographic techniques like encryption, hashing, and digital signatures. It discusses symmetric and asymmetric encryption standards and their applications to secure communications and protecting stored data. The document emphasizes the importance of security updates, firewalls, intrusion detection systems and having expertise in cyber security.

1. Network Security
and Cryp ography
Ansh Bhawnani

2. “Your network is your net worth.
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3. Network Security and Cryptography
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Network Security

4. Network Security
4
What is Security?

5. Network Security
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Network Security Principles

6. Confidentiality
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1

7. Integrity
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2

8. Availability
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9. Network Security
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10. Network Security
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But why Security?

11. Network Security
▰ Only allow access to those who need it
▰ Provide authentication and access
control
▰ Guarantee availability of resources
▰ To not lose millions!
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12. Network Security
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Network Security Attacks

13. “The way the networking works, is
actually it’s own weakness.
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14. Network Security
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1.Passive Attacks

15. Network Security
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16. Network Security
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2. Active Attacks

17. Network Security
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18. Network Security
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1.Man in the Middle
Attack
This is where the destruction begins

19. Man in the Middle Attack (MiTM)
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20. Man in the Middle Attack (MiTM)
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How does it happen?

21. ARP Poisoning
Man in the Middle Attack (MiTM)
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▰ ARP- Links IP address with MAC addresses
▰ ARP Poisoning/spoofing means faking a network
device
▰ Attacker will exploit working of the ARP protocol
▰ Attacker can forge an ARP packet with his MAC for a
legitimate IP address

22. ARP Poisoning 22
ARP Working

23. ARP Poisoning 23
ARP Poisoning

24. DNS Poisoning/Spoofing
Man in the Middle Attack (MiTM)
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▰ Consequence of MiTM attack
▰ Exploitation of the DNS system
▰ Attacker is in the middle of DNS server and victim
▰ Attacker sends any IP he wants in response

25. DNS Poisoning 25
DNS Poisoning

26. Network Security
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2. Denial of Service

27. DoS Attack 27
Denial of Service (DoS)

28. DDoS Attack 28
Distributed Denial of Service (DDoS)

29. Network Security
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3. Eavesdropping

30. Network Security
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4. Password Based Attacks

31. Password Based Attacks
Brute Force
▰ Simultaneously
try any huge
number of
random strings
Dictionary Based
▰ Target Specific
▰ Try every
combination from
a text/dictionary
file
Rainbow Tables
▰ Large file with
precomputed
hashes of strings
▰ Cracking very
fast, matter of
seconds
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32. Network Security
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5. Social Engineering
Which has no cure.

33. Network Security
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What about “Security” then?

34. Network Security and Cryptography
34
Cryptography

35. Cryptography
▰ Study of techniques for secure communications
through insecure channels
▰ Fulfills confidentiality, integrity and non-repudiation
▰ Teaches how to convert sensible data into random
junk!
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36. Cryptography
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37. Cryptography
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38. Cryptography
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Cryptography Terms

39. Cryptography
Plaintext
▰ Original message
▰ Anyone can read
▰ E.g, “Alice”
Cipher key
▰ Cryptographic
function
▰ Tells how to
transform
plaintext into that
random junk
Cipher text
▰ That random junk
we got after
applying cipher
key on plaintext
▰ Unreadable,
useless
▰ E.g., “#r4Tf2%#”
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40. Cryptography
Hash
▰ Random fixed length string
▰ Irreversible one way function
▰ Provides integrity
▰ E.g., MD5, SHA-1
Salt
▰ Additional security
▰ Eradicates brute force and
cracking
▰ Appended at beginning or end of
plaintext
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41. Cryptography
Block cipher
▰ Divide a message into fixed size
blocks
▰ Encrypt each block individually
▰ Integrate all the outputs to obtain
final ciphertext
Stream Cipher
▰ Encrypt the message as a
sequence of bytes
▰ Encrypt the data bit by bit
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42. Cryptography
Private key
▰ No question of sharing!
▰ Used for decrypting
▰ Completely confidential
▰ Limit only to yourself, that too in
your deepest vaults!
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Public key
▰ Used for encrypting data
▰ Not confidential, boast about it!
▰ Your partner should have it!

43. Cryptography
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Cryptanalysis
▰ Study of ciphertext and cryptosystems
▰ To find how they work, internally
▰ To break them
▰ Reversing the techniques of cryptography

44. Cryptography
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Types of Cryptography

45. Types of Cryptography
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46. Cryptography
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1. Symmetric Encryption

47. Symmetric Cryptography
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48. Cryptography
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Encryption Standards

49. Cryptography
Advanced Encryption Standard (AES)
▰ Block cipher based on Rjindael
▰ Used for decrypting
▰ Completely confidential
▰ Limit only to yourself, that too
in your deepest vaults!
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Data Encryption Standard (DES)
▰ Most widely used block cipher
▰ Introduced in 1977 by NIST
▰ Block Size- 64 bit
▰ Key size- 56 bit

50. Cryptography
50
Disadvantages of Symmetric Encryption
▰ Problem of key exchange
▰ Digital Signatures not applicable
▰ Known attacks

51. Cryptography
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2. Asymmetric Encryption/
Public Key Cryptography

52. Asymmetric Cryptography
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53. Cryptography
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Types of Public Key Cryptography
▰ Rivest Shamir Adleman (RSA)
▰ Elgamal
▰ Diffie Hellman
▰ Elliptical Curve

54. Cryptography
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Applications of Cryptography
▰ Secure Communications over insecure channels (public)
▰ End to End Encryption
▰ Asymmetric- Exchanging session keys for symmetric
communications
▰ Protecting data at rest (passwords, social, card numbers,
etc.)
▰ Digital Signatures

55. Network Security
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Firewalls

56. Network Security
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Intrusion Detection
Systems (IDS/IPS)

57. Network Security
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UPDATE, UPDATE, UPDATE!!

58. Network Security
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Stay smart, Boycott Stupidity

59. Network Security is not singular
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60. Network Security and Cryptography
Neglecting security
in life is where IoT
becomes Internet
of Threats.
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61. 80%<
This much companies face lack of
expertise in cyber security, in India!
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THANKS!
Any questions?