1. Security in Network Communications
Deepti Reddy
Suphannee Sae Chai
Sarah Summers
11/28/2018
CS522 Computer Communications

2. Presentation Overview
Motivation
Communication Security Issues
Secure
11/28/2018
CS522 Computer Communications

3. CS522 Computer Communications
Motivation
Network Communications are a fact of every day life.
Need to protect sensitive information.
Need to control access.
11/28/2018
CS522 Computer Communications

4. Communication Security Issues
Confidentiality
Authentication
Integrity
Non-repudiation
11/28/2018
CS522 Computer Communications

5. Email Security Protocols
PGP (Pretty Good Privacy)
PEM
S/MIME
11/28/2018
CS522 Computer Communications

6. PGP (Pretty Good Privacy)
Hybrid Crypto System
Combines Features of Symmetric and Asymmetric Cryptography
Confidentiality
Authentication
Digital Signatures
Compression
11/28/2018
CS522 Computer Communications

7. CS522 Computer Communications
How PGP Works
Preprocessor invoked by user
Compresses plaintext using MD5
Resulting Hash encrypted using RSA with sender’s private key
PGP concatenates encrypted hash and original message into single message and compresses it using a ZIP programme
11/28/2018
CS522 Computer Communications

8. CS522 Computer Communications
How PGP Works?
PGP generates a session key using the IDEA algorithm
Key generated from random key strokes and mouse movements
Session key encrypted using receiver’s public key
Encrypted session key and zipped message are concatenated and converted to base 64
11/28/2018
CS522 Computer Communications

9. CS522 Computer Communications
PGP Encryption
11/28/2018
CS522 Computer Communications

10. CS522 Computer Communications
Future Work
Staying ahead of attackers by developing stronger algorithms and security techniques.
Modification of current protocols.
Creation of new protocols.
11/28/2018
CS522 Computer Communications

11. CS522 Computer Communications
Conclusions
Network Communications security is a broad and complex subject.
Cryptographic methods are the solution.
Security mechanisms will always be attacked and eventually broken.
11/28/2018
CS522 Computer Communications

12. Questions ? Under Pain of Death!
11/28/2018
CS522 Computer Communications

13. CS522 Computer Communications
References
[1] Communication Security – available techniques, AXIS Communications White Paper,
[2] IDEA (International Data Encryption Algorithm)
[3] International Data Encryption Algorithm – Technical Description,
[4] How PGP Works,
11/28/2018
CS522 Computer Communications

14. CS522 Computer Communications
IDEA ALGORITHM
International Data Encryption Algorithm
Block Cipher Algorithm
Operates on 64 bit plaintext and cipher text blocks
Utilizes 128 bit key
11/28/2018
CS522 Computer Communications

15. CS522 Computer Communications
How IDEA Works
Comprised of 8 identical encryption processes (rounds) followed by a final output transformation
Plaintext partitioned into four 16 bit sub-blocks
Three operations used to combine two 16-bit values to produce a 16-bit result - addition, XOR and multiplication
11/28/2018
CS522 Computer Communications

16. How IDEA Works (conitnued)
11/28/2018
CS522 Computer Communications