Mathematics

Mathematics

Cryptography and Security

Cryptography and Security

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Cryptography is the art and science of achieving security by encoding messages to make them non-readable.

Cryptanalysis is the technique of decoding messages from a non-readable format back to readable format without knowing how they were initially converted from readable format to non-readable format.

Cryptology is a combination of cryptography and cryptanalysis.

Principles of Security:-

1)Confidentiality
2)Integrity
3)Authentication
4)Access control
5)Availability
6)Non-repudiation
7)Ethical and legal issues

Types of attacks:-

1)General attacks-

Criminal attacks,publicity attacks,legal attacks

2)Technical view-

a)Theoretical concepts-
I)Passive attacks-

i)release of message contents

 ii)traffic analysis

 
II)Active attacks-

i)Interception,

ii)Fabrication,

iii)Modification,

iv)Interruption

3)Program attack-

a)Virus- A virus is a computer program that attaches itself to another legitimate program and causes damage to the computer system or to the network.

During lifetime ,a virus goes through four phases:-
Dormant phase,Propagation phase,Triggering phase ,Execution phase.

b)Worm

A worm does not perform any destructive actions and instead ,only consumes system resources to bring it down.

c)Trojan Horse

It allows an attacker to obtain some confidential information about a computer or a network.

d)Specific attacks-

Sniffing and spoofing-cause packet level attacks.

Phishing-It is new attack which attempts to fool legitimate users to provide their confidential information to fake sites

Pharming  /DNS spoofing -attack involves changing the DNS entries so that users are redirected to an invalid site,while they thinking that they have connected to the right site.