This document discusses information security goals of confidentiality, integrity, and availability. It describes two types of cryptographic attacks: cryptanalytic attacks which try to ascertain a secret key through statistical or algebraic techniques, and non-cryptanalytic attacks which threaten the security goals. Non-cryptanalytic attacks include snooping, traffic analysis, modification, denial of services, repudiation, replaying, and masquerading. Attacks can be either passive, where the goal is just obtaining information without modifying data, or active, where the attacker may change data or harm the system. Passive attacks are difficult to detect while active attacks are easier to detect.

1. Mr. Pawar R.B.
Information Network Security

2. Introduction:
 Information is an asset
 Security Goals
 Confidentiality:
 Not only storage information but also transmission of
information
 Integrity:
 Changes need to done by authorized entities
 Availability:
 Information available when needed to the authorized
entities.

3. Cryptographic Attacks
 Two Types
1. Cryptanalytic Attacks:
 Combination of statistical and algebraic techniques
aimed at ascertaining the secret key of a cipher
 Efficient attacks will try “divide and conquer” strategy to
reduce the complexity of guessing the key from the brute
force search complexity
 An attack is successful if the guessing complexity is
lesser than brute force search complexity, although it
may be practically infeasible
2. Non-cryptanalytic Attacks:
 It threaten to security goals (confidentiality, integrity &
availability)

4. Non- cryptanalytic Attacks
Threat to
availability
Threat to confidentiality
Threat to integrity
Fig: Taxonomy of attacks with relation to security goals
Security
Attacks
Snoopin
g
Traffic
Analysis
Modificatio
n Denial of
Services
Repudiatio
n
Replaying
Masquerad
ing

5.  Snooping:
 unauthorized access to or interception of data
 Traffic Analysis:
 It can obtain some other information by monitoring
online traffic.
 Modification: after accessing the information, the
ataacker modifies the information to make it beneficial to
herself.
 Masquerading: masquerading or snooping happens
when the attacker impersonates somebody else.
 Replaying: attacker obtains a copy of a massage sent by
a user and later tries to replay it.
 Repudiation: it is different from others becoz it is
performed by one of the two parties in the

6. Passive Vs Active Attacks
Attacks Passive / Active Threatening
Snooping, Traffic analysis Passive Confidentiality
Modification,
Masquerading, Replay,
Repudiation
Active Integrity
Denial of Services Active Availability
 Passive Attacks:
 The attacker goal is just to obtain information
 Does not modify data or harm the system
 Difficult to detect until the sender or receiver finds out about
leaking of confidential information
 Can be prevent by encipherment
 Active Attacks:
 May change the data or harm the system
 Easier to detect than to prevent