6. Asymmetric-Key Cryptography
In an asymmetric-key cipher, a pair of keys is used. The sender uses the public
key. The receiver uses the private key.
7. Security Services
A network can provide on of the five services given below:
Message Confidentiality
Message Integrity
Message Authentication
Message Nonrepudiation
Entity Authentication
9. Security in the Internet
IPSec for IP Protocol.
SSL for TCP Protocol
PGP for SMTP Protocol.
Firewalls
10. IP Security (IPSec)
IP Security(IPSec) is a collection of protocols designed by the IETF to provide
security for a packet at the network level.
Two Modes: Transport Mode, Tunnel Mode
Two Security Protocol: AH Protocol, ESP Protocol
11. SSL/TLS
It is a transport layer protocol that give end-to-end service for transactions on
the Internet.
SSL Protocols TLS Protocols
Handshake Handshake
Alert Alert
Record Record
Change Cipher Spec Protocol
12. PGP
Provide security at the application layer.
Services:
Plaintext
Message Authentication
Compression
Confidentiality with One Time Session Key
Code Conversion
Segmentation
13. Firewalls
A firewall is a device installed between the internal network of an organization and
the rest of the Internet.
Packet-Filter Firewall: It filters at the network or transport layer.
Proxy-Filter Firewall: It filters at the application layer.