DCN_rpj15

DCN_rpj15 - NT503: Data Communication & Networking...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Network Security
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Security requirements Confidentiality of information • Unauthorized person should not gain access Integrity of information • Information content must be received in its original form, without getting altered Availability of information • Information must be available on request • Two types of attacks are possible: –Pa s
Background image of page 2
3 Security threats
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Passive attacks Eavesdropping (or tapping) the ongoing transmissions to obtain information. Two Types of passive attacks, – Read only access to the message contents • Intruder taps the contents of transmission – Traffic analysis: • By monitoring frequency and length of encrypted messages, nature of communication can be guessed Difficult to detect, but easy to prevent Can be prevented by physically securing the medium
Background image of page 4
5 Active attacks Masquerade – Pretending to be a different entity – e.g. Capture authentication sequence and replay after valid authentication to get extra privileges •R e p l a y : – Capture of data units and retransmission Modification of messages: – Modify/delay/reordered the message
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 Cryptography ¾ Cryptography means secret writing ¾ It can also mean art of transforming messages to make them more secure and immune to intruder attacks ¾ An intruder refers to any unauthorized person trying to steal the information
Background image of page 6
7 Ciphers ¾ Cipher refers to encryption and decryption algorithms Encryption Algorithm + Plain text Cipher text Decryption Algorithm + Cipher text Plain text ¾ Cipher refers to encryption and decryption algorithms
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon