NETWORK SECURITY-K.GAYADRI-II-MSC COMPUTER SCIENCE
- 1. BIG DATAANALYTICS SUBMITTED BY NAME:K.GAYADRI CLASS:II-M.SC,COMPUTER SCIENCE BATCH:2017-2019 INCHARGE STAFF:MS.M.FLORENCE DAYANA
- 2. The problem is that given the OSI Network Model of: Application, Transport, Network, Datalink and Physical, where amongst this can security be deployed? Should everything be concentrated at the data link or network or transport… layers? or should a Defence in Depth strategy be employed? These notes details the various ways in which networks can be made secure. The remainder of this chapter provides some introductory material in relation to networks and their security. First, some terminology: • Security Attack: Any action that compromises the security of information exchanges and systems. • Security Service: A service that enhances the security of information exchanges and systems. A security service makes use of one or more security mechanisms. • Security Mechanism*: A mechanism that is designed to detect, prevent or recover from a security attack.
- 3. . Security Attacks There exist several attack types and they can be divided into two distinct category’s: Passive and Active, they denote the amount of work that an attacker must do. 2.1.1. Passive Attacks A Passive Attack is one that involves either the eavesdropping or monitoring of data communications. The goal of the malicious entity is to acquire the information or learn more about the communication. Traffic Analysis: Traffic analysis is concerned with the analysis of patterns generated by the actions of the parties involved. This may simply involve the detection of an encrypted message being sent from a single party. Such attacks are difficult to detect, due to their inherent nature. Though one can use encryption in order to inhibit the success-fullness of such attacks.
- 4. Active Attacks Active Attacks are those that involve the modification of the communication channel or the data being sent across the channel. • Masquerade: This is simply the impersonation of a legitimate entity in order to abuse or access the resources accessible by the entity. • Replay: Involves the retransmission of existing and already transmitted data in order to produce an unauthorized effect. • Message Modification: The delay, modification, reorder on a legitimate message such that it produces an unauthorized effect. • Denial of Service: This involves the prevention of or reduction in quality, of a legitimate service. Such attacks may target specific hosts or entire networks. In contrast to passive attacks, active ones are easy to detect but harder to counter, as it would involve the protection of all the communication services offered.
- 5. A Security Service, as defined by X.800, is a service provided by a protocol layer of communicating open systems, which ensures adequate security of the systems or data transfers. There are five ctegories mentioned, together with availability: Availability The property of a system or a system resource being accessible and usable upon demand by an authorized system entity, according to performance specifications for the system. Access Control The prevention of unauthorized use of a resource. Authentication This is the assurance that the communicating entity is the one that it claims to be. There are two classes of authentication:
- 6. Data Confidentiality The protection of data from unauthorised disclosure. This can be further specified as: • Connection Confidentiality — The protection of all user data on a connection. • Connectionless Confidentiality — The protection of all user data in as single data block. • Selective-Field Confidentiality — The confidentiality of selected fields within the user data on a connection or in a single data block. • Traffic-Flow Confidentiality — The protection of the information that might be derived from observation of traffic flows.
- 7. Data Integrity The assurance that data received is in the exact same format as it was when sent by an authorised entity. This can be considered in terms of Connection Integrity: • Connection Integrity with Recovery — Provided for the integrity of all user data on a connection and detects any modification, insertion, deletion or replay of any data within an entire data sequence, with recovery attempted. • Connection Integrity without Recovery — As previously but provides only detection without recovery. • Selective-Field Connection Integrity — Provides for the integrity of selected field within the user data of a data block transferred over a connection and takes the form of determination of whether the selected fields have been modified, inserted, deleted or replayed.
- 8. Security Mechanisms refer to tools and techniques that can be implemented within a specific protocol layer or out with the layer that provided some form of security. Some examples are listed below. Specific Mechanisms Encryption, Digital Signatures, Access Control, Data Integrity, Authentication Exchange, Traffic Padding, Routing Control, Notarisation Pervasive Mechanisms Trusted Functionality, Security Label, Event Detection, Security Audit Trail, Security Recovery
- 9. a. Design an algorithm for performing the security related transformation. b.Generate the secret information that is to be used. c.Develop method for distribution and sharing of the secret information. d.Specify a protocol to be used by the two principals that utilises the security algorithm and secret information to achieve a particular security service. 2.4.2. Secure Systems
- 10. Secure System The other model reflects the remainder of the security problems that are associated with the protection of an information system i.e. a network, from malicious entities
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