internet security Flashcards
Methods of IntSec
Firewalls
Digital Signatures
Encryption
Firewalls
Sits inbetween client and internet, regulating packets that pass through. Also acts as a proxy server which can perform packet filtering and stateful inspection.
Packet Switching
Stateless method (doesn’t inspect contents of the packet)
Blocks packets based on the source IP address or port number (protocol its using)
IPs and Ports can be blacklisted
Stateful Inspection
Examines content in the payload
Can filter out packets based on current network activity
Proxy Server
Sits between private and public networks
Manage individual packets
Firewall Process
A transmits
Firewall’s IP is used to send
B’s firewall receives packets
Hence there’s a degree of anonymity
Types of encryption
Asymmetric
Symmetric
Symmetric Encryption
Sender and receiver have same private key
Used to decrypt and encrypt at both ends
Key exchange could be intercepted - man in the middle attack
Asymmetric Encryption
Encrypted with recipient’s public key
Can only be decrypted using the recipients private key
Digital Signatures
Verifies the sender and integrity of the message
Digital Signature Process
- Digest of a message is created (checksum or hashing)
- Encrypted with sender’s private key (anyone with recipient public key can decrypt)
- Encrypted with recipient’s public key
- Decrypted with recipients private key
- Decrypted with sender’s public key
- Carries out checksum/hashing to determine if message is intact
Digital Certificate
Checks to see if the key pair being used is real
Stores: serial number, owner’s name, expiry date, public key and certificate authority signature
Worms
Malicious software that can replicate between computers
Trojans
Disguised as a file that users are tricked into clicking
Viruses
Require an executable host file to reside in
