Nowadays three main objectives for computer security. They are

Nowadays wehave become much dependent on computers for banking, healthcare, shopping,telecommunication Security has now become a basic requirement because computersand other resources have become inherently insecure. Security issues likeDenial of Service, TCP SYN Flooding attack, Packet Dropping attacks and DistributedDenial of Service attacks are some of the methods by which unauthorized usersmake the resource unavailable to authorized users. There are several securitymechanisms like Intrusion Detection System, Anomaly detection, Trust models bywhich we can be able to detect and prevent misuse of computer resources byunauthorized users.

This paper presents a survey of several security mechanismswhich have been implemented using Fuzzy. Fuzzy logic is one of the rapidlydeveloping technology which is used in sophisticated control system. Fuzzylogic deals about the degree of truth rather than the Boolean logic whichcarries the values of either true or false. So instead of providing only twovalues we will be able to define intermediate values.Keywords—Fuzzylogic; Security;Denial of Service; Distributed Denial of Service; IntrusionDetection System; Trust Management                                                                                                                                                     I.

      IntroductionThere is a need to protect information from unauthorizedaccess while also still allowing access to those who need it. It is also a needfor a system in places which guarantees the availability of resources at alltime. An organization has to protect the data it collects and uses. So therehave been the need to provide security mechanism which can be used to detectand prevent disclosure, leaking of data to unauthorized parties.In general, there are three main objectives for computersecurity. They are Confidentiality, Integrity and Availability.

Confidentialityis the steps taken to ensure that the sensitive information is not disclosed oraccessed by wrong people. Confidentiality is similar to privacy. Integrityensures that the data is not altered by unauthorized persons.

Also, Integrityis to ensure that the accuracy, consistency and trustworthiness of data ismaintained at all time. Availability is to make sure that the resources areavailable to users at all times. If availability is not maintained this willlead to denial of service attacks.

The term fuzzy logic was first coined by Lotfi Zadeh inthe year 1965. But Fuzzy logic had been studied as infinite-valued logic 1920s.Before the advent of Fuzzy logic there was Classical logic. It was known to beas bivalent logic which means that it can accept only two possible truth valueseither true or false. Whereas Fuzzy logic is a multi-valued logic which canallow intermediate values.

Since it can be used to accept multi values it hasthe ability to accept the concept of partial truth. Fuzzy logic in general willdeal about the degree of truth. Approaches other than fuzzy logic need accurateequations to model real world behaviour whereas a fuzzy based design canaccommodate the ambiguities of real world human language and logic.                                                                                                                 II.    Backgroundof security mechanismsAs mentioned inprevious section there are three main objectives for a computer security namelyConfidentiality, Integrity and Availability. They are commonly referred to asCIA Triad as mentioned in Fig.

1.Fig.1.Objectives of Computer security.There aredifferent methods by which the Confidentiality of the data be maintained. Thefirst method is authentication. Authentication will ensure that only authorizedusers who have user identification and password are allowed access the data.

Theother method to maintain the confidentiality is to enforce access control andfile permissions. The other most common method is by the process of encryptionand decryption. Encryption is the process of converting from plain text tocipher text and decryption is the process of converting from Cipher text toplain text.

Integrity isused to make sure that the data is not being altered by unauthorized parties.The best method to protect the integrity of data is by hashing the data. In ahash function, the sender generates a hash function of the message and appendsit with the original message. At the receiver end the receiver splits themessage and hash function. The receiver then recalculates the hash value forthe message. If this hash value matches with the hash value sent by the sendermatches, then the message received is unaltered else it is altered.

Availability isto make sure that the computer resources are available to authorized users atall times. The best available method for availability is by redundancies. Someof the other means to protect availability is using ant-virus software andIntrusion Detection System.The followingare some of the security mechanisms followed by Users, Organizations to protecttheir sensitive data from unauthorized users. A.    IntrusionDetection SystemAn Intrusion Detection System is a software application ora hardware device that will be used to monitor the network traffic for maliciousactivity and reports the same to the system or the network administrator. Themain difference between a firewall and IDs is that firewall cannot stop anattack which occurs within the network whereas an IDS can be able to detect attacksthat originate from within a system. This is possible since it will examine thenetwork communications.

An example of IDS is shown in Fig.2 below.Fig.

2. Intrusion Detection System.There are two common types of Intrusion Detection Systemsavailable. The first type is called as Network Intrusion Detection System(NIDS).NIDS is used to monitor the network traffic of all the devices that areconnected within the network. For instance, if a NIDS is installed near afirewall, the NIDS can raise an alarm if someone tries to break a firewall.

The second type is known as Host Intrusion DetectionSystem (HIDS). An HIDS is a type of IDS where the incoming and outgoing packetsof a particular device is monitored If a suspicious activity is detected, then HIDSwill alert the user or the administrator.