Monday, October 26, 2009

Lec 10 : Cyberlaws

In the chapter we learn about cyberlaw. Cyberspace is being governed by a system of law and regulation called Cyberlaw. There is no one exhaustive definition of the term “Cyberlaw”. Simply speaking, Cyberlaw is a generic term which refers to all the legal and regulatory aspects of Internet and the World Wide Web. Anything concerned with or related to or emanating from any legal aspects or issues concerning any activity of netizens and others, in Cyberspace comes within the ambit of Cyberlaw. The growth of Electronic Commerce has propelled the need for vibrant and effective regulatory mechanisms which would further strengthen the legal infrastructure, so crucial to the success of Electronic Commerce.

Cyberlaw is important because it touches almost all aspects of transactions and activities on and concerning the Internet, the World Wide Web and Cyberspace. Initially it may seem that Cyberlaws is a very technical field and that it does not have any bearing to most activities in Cyberspace. But the actual truth is that nothing could be further than the truth. Whether we realize it or not, every action and every reaction in Cyberspace has some legal and Cyber legal perspectives

Tuesday, October 20, 2009

Lec 9 : Legal and Ethical Issues in Computer Security

In this chapter we study controls applicable to computer security the legal system and ethics. The legal system has adapted quite well to computer technology by reusing some old forms of legal protection and creating laws where no adequate ones existed. Still, the courts are not a perfect form of protection for computer resources. This is, we have to wait for a transgression to occur and then adjudicate t, rather than try to prevent it n the first place. Second, fixing a problem through the courts can be time consuming and expensive, the latter characteristic prevents all but the wealthy form addressing most security issues.

On the other hand, ethics has not bad to change, because ethics is more situational and personal than the law. And although technically this issue is just an aspect of confidentiality, practically it has log history in both law and ethics. This chapter too discuss is round out study of protection for computing system by understanding the context in which security is assessed and applied. Not always are conflict resolved pleasantly. Some people will think that they have been treated unfairly, and some people do indeed act unfairly.

Law and computer security are related in several ways. First, international, federal,state,and city laws can affect privacy and secrecy. These statues often apply ti the rights of individuals to keep personal mattes private. Second, laws regulate the use, development and ownership of data and programs. Patents, copyrights and trade secrets are legal devices to protect the rights of developers and owners of programs and data. Similarly, one aspect of computer security id controlling access to programs and data that access control is support by the mechanisms.

Thursday, October 15, 2009

Lec 8: Wireless Security

The chapter 8 we learn about the wireless security.Wireless network specifications ware originally defined in IEEE's 802.11 standard.There are now a series of 802.11 standard, and various implementations of wireless network now occupy several more 802 standard. The original 802.11 standard contained several security measures, including
- Disable the services set identifier (SSID) broadcast
- MAC addressing filtering
- Wired Equivalent Privacy (WEP) authentication
- WEP data encryption

Security in 802.11 was found to be seriously flawed in several areas 802.11 was developed to correct the shortcomings of security in 802.11. The WiFi also improved security for wireless networks with WiFi protected Access (WPA, WPA2) for home network use, called personal, and for business network use, called Enterprise. WPA uses an acceptable encryption algorithm that is strong and easier on the devices performing the encryption. WPA2 uses a significantly stronger algorithm that is considered uncrackable, but the performence of devices may suffer with the heavy work load.

Thursday, October 1, 2009

Lab 7 : Security in Application

In lab 7 we learn about security in application. In the lab 7 mostly we learn about FTP. File Transfer Protocol (FTP), a standard Internet protocol, is the simplest way to exchange files between computers on the Internet. Like the Hypertext Transfer Protocol (HTTP), which transfers displayable Web pages and related files, and the Simple Mail Transfer Protocol (SMTP), which transfers e-mail, FTP is an application protocol that uses the Internet's TCP/IP protocols. FTP is commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet.

As a user,can use FTP with a simple command line interface (for example, from the Windows MS-DOS Prompt window) or with a commercial program that offers a graphical user interface. Your Web browser can also make FTP requests to download programs you select from a Web page. Using FTP, you can also update (delete, rename, move, and copy) files at a server. You need to logon to an FTP server. However, publicly available files are easily accessed using anonymous FTP.

Basic FTP support is usually provided as part of a suite of programs that come with TCP/IP. However, any FTP client program with a graphical user interface usually

Tuesday, September 29, 2009

Lec 7 : Security Application

In the chapter 7 we learn about security application. In this chapter we must know about electronic mail security and what it is and how it works. In security provided in email is confidentiality , data origin authentication, message integrity, non-repudiation of origin and key management. We must to know how emails transported in when user used email. Mostly in this chapter about email security and threats. We must know how to secure the web. In HTTPS we must know access control.Nowadays, the
world is become expand especially in term of technology. For example, biometric technology and fingerprint recognition. At the same time, it also came with
advantage and disadvantage.

Wednesday, September 23, 2009

lab 6 Database security

In the Lab we learn about database security. In this lab we must to understand about the importance of security in database system and integrated potential implement of security in database.In this lab too, we should menage the record

Lec 6: Security In Network

In this chapter, we learn about the security in the network. Security is a very difficult topic.The sub topic important this chapter is Introduction to Network Who, cause security problem, Network security issues, Network security controls. Everyone has a different idea of what "security" is,and what levels of risk are acceptable. The key for building a secure network is to define what security means to your organization . Once that has been defined, everything that goes on with the network can be evaluated with respect to that policy. Projects and systems can then be broken down into their components, and it becomes much simpler to decide whether what is proposed will conflict with security policies and practices.

It's important to build systems and networks in such a way that the user is not constantly reminded of the security system around him. Users who find security policies and systems too restrictive will find ways around them. It's important to get their feedback to understand what can be improved, and it's important to let them know why what's been done has been, the sorts of risks that are deemed unacceptable, and what has been done to minimize the organization's exposure to them.

Monday, September 21, 2009

Lec 5 : Database Security

Database security is the system, processes, and procedures that protect a database from unintended activity. Unintended activity can be categorized as authenticated misuse, malicious attacks or inadvertent mistakes made by authorized individuals or processes. Database security is also a specialty within the broader discipline of computer security.

Traditionally databases have been protected from external connections by firewalls or routers on the network perimeter with the database environment existing on the internal network opposed to being located within a demilitarized zone. Additional network security devices that detect and alert on malicious database protocol traffic include network intrusion detection systems along with host-based intrusion detection systems.

Database security is more critical as networks have become more open.

Databases provide many layers and types of information security, typically specified in the data dictionary, including:

* Access control
* Auditing
* Authentication
* Encryption
* Integrity controls

Database security can begin with the process of creation and publishing of appropriate security standards for the database environment. The standards may include specific controls for the various relevant database platforms; a set of best practices that cross over the platforms; and linkages of the standards to higher level polices and governmental regulations.

Monday, September 7, 2009

Lab 5 Web Application Security

1. Make Sure You Have Java
2. Web Application Hacking simulation using WebGoat and WebScarab, if u want download this sofware, click the link above :
http://www.owasp.org/index.php/Category:OWASP_WebGoat_Project http://www.owasp.org/index.php/Category:OWASP_WebScarab_Project

Command Prompt opens and vanishes instantly, and another Command Prompt window opens titled "Tomcat". The Tomcat window fills with text and stays open, as shown below. This is the Apache Tomcat Web server listening on the localhost, port 80.
Open Firefox, go to http://localhost/WebGoat/attack. A box pops up asking for a name and password. Use guest for both the name and the password. The main WebGoat page opens. Click the "Start WebGoat" button. The "How to work with WebGoat" page opens, as shown belo

Installing WebScarabYou need WebScarab to complete the lessons. Go to this link. On the left side, click the Download link. In the first sentence in the Download section, click the word "here". Save the webscarab-current.zip file. Extract it. A folder named webscarab-current appears. Double-click the subfolder named webscarab-20090222-2217. Double-click the webscarab.jar file. Webscarab opens. This is the Lite Interface. From the menu bar, click Tools, Use Full-Featured Interface. Close WebScarab and restart it. Now you should see many more options, as shpwn below.



Sunday, August 16, 2009

Lab 4 : Cryptography Extended

Caesar Cipher

A cipher or cryptosystem is a method for message concealment.
The key provides the means for efficient encipherment (encryption).

Plaintext – message in readable form
Ciphertext – encrypted message


example the plaintext encrypted to get the cipher text in


The term steganography is applied to the activity of hiding the existence of a
message.
Cryptanalysis gets extended to other contexts where the messages are hidden (or suspected to e hidden) in text, pictures, music, etc.

Symmetric (or classic secret-key) cryptology relies on the correspondents agreeing on key information over the key (secure) channel.

Asymmetric (public-key) requires two key steps
- one key for encipherment
- A second key for decipherment


Vigenere Cipher

Explanation
EACH column of this table forms a dictionary of symbols representing thealphabet: thus, in the A column, the symbol is the same as the letterrepresented; in the B column, A is represented by B, B by C, and so on.

To use the table, some word or sentence should be agreed on by twocorrespondents. This may be called the `key-word', or `key-sentence',and should be carried in the memory only.
In sending a message, write the key-word over it, letter for letter,repeating it as often as may be necessary: the letters of the key-wordwill indicate which column is to be used in translating each letter ofthe message, the symbols for which should be written underneath: thencopy out the symbols only, and destroy the first paper. It will now beimpossible for any one, ignorant of the key-word, to decipher the message,even with the help of the table.
RSA algorithm
The RSA algorithm is one of the earliest, yet most versatile public key algorithm
The original intent for this algorithm is for keyestablishment/transfer, signing/verification, data integrity, and encryption/decryption
To honour them, the method was referred to as the RSA Scheme. The system uses a private and a public key. To start two large prime numbers are selected and then multiplied together; n=p*q.
RSA takes advantage of the fact that prime numbers are easy to compute and factoring them is reasonably difficult

Friday, August 14, 2009

Lec 4: Operating System Security

In this chapter learn about operating system security. First the concept of a protection defines that the system component that enforces the access control in an operations system. A protection system consists of a protection state which describes the operations that are permitted in a system protection state operations which describe how the protection state may be changed. from this, we can determine the operations that individual processes perform

second, we identify that the today commercial operating system use protection systems that fail so truly enforce security goals. we defined a mandatory protection system which will enforce security in the face of attack

third, we outline the architecture of an access enforcement mechanism that would be implemented by a protection system. Such enforcement mechanisms can enforce a mandatory protection state correctly if they satisfy the guarantee required of the reference monitoring concept

Finally, we defined requirements for a secure operating system based on a reference monitor and mandatory protection style.

Monday, August 10, 2009

Lab 3: Authentication and Basic Cryptography

Encrypting a File or Folder

To encrypt a file or folder from the GUI, follow these steps:
a. Open Windows Explorer or My Computer.
b. Right-click the file or folder that you'd like to encrypt or unencrypt and select Properties.
c. On the General tab, click the Advanced button.
d. From the Advanced Attributes dialog box, mark (or clear) the Encrypt Contents to Secure Data check box to encrypt (or unencrypt) the file or folder that you selected. Click OK to close the Advanced Attributes dialog box and then click OK for the properties sheet to apply this setting. (When you encrypt a folder, you are prompted to select between applying this setting to the folder only and applying it to the folder, subfolders, and files.)
e. To share access to an encrypted file, click the Details button from the Advanced Attributes dialog box. You cannot share access to encrypted folders.
f. From the Encryption Details dialog box, click the Add button to add more users' EFS certificates to the encrypted file to share access with those users.
g. From the Select User dialog box, click the user whose EFS certificate you want to add for shared access to the encrypted file and click OK. You see only certificates for users who have encrypted a folder or file previously.
h. Click OK for the Encryption Details dialog box.
i. Finally, click OK for the Advanced Attributes dialog box and then click OK for the Properties window





Account Lockout Policy
You can access Group Policy settings by opening the Microsoft Management Console (MMC) and adding the Group Policy snap-in.
The Acount Lockout Policy controls settings related to users attempting to login and entering wrong passwords. While it is possible to set this up so that a person can sit there and try thousands of different passwords in an attempt to find the right one, this is highly unwise and a serious compromise of security. There are three settings for this policy and using them will greatly increase security.
Access the Account Lockout Policy from:
Computer Configuration -> Windows Settings -> Security Settings -> Account Policy -> Account Lockout Policy

The three settings that you can set are: Account Lockout Duration, Account Lockout Threshhold, and Reset Account Lockout After. I recommend setting Account Lockout Threshhold to "5 Invalid Login Attempts". When you do this, it will automatically set the other two settings to "30 Minutes". When you apply these settings, a user will become completely locked out of the system for 30 minutes if they enter the wrong password 5 times.

Password Policy
The Password Policy controls settings related to each user's passwords. It is important to enforce a password policy, because the chances of a user giving out their password (accidently or intentionally) is very high. Thus, requiring them to change their password reasonably often and have it conform to a set of standards that make it very difficult to crack is in your organization's best interests.

Access the Password Policy from:
Computer Configuration -> Windows Settings -> Security Settings -> Account Policies -> Password Policy

There are five settings here that you can set. They are: Enforce Password History, Maximum Password Age, Minimum Password Age, Minimum Password Length, and Password Must Meet Complexity Requirements. I recommend that you enforce a password history that is a minimum of 6. This means that a user must change their password six times before they can reuse a password.

For Maximum Password Age, I recommend between 30 and 40 Days - this forces users to change their password every number of days specified in this setting.

Minimum Password Age is also important, because it requires users to use their password a certain amount of time before changing it. A smart user could figure out your system and change their password six times in a row, thus bypassing the password change and compromising your network. I recommend a Minimum Password Age of 1 day, and preferably 7 days. For Minimum Password Length, most enterprises require a minimum length of 8, or sometimes 12. The longer the password, the harder it is to crack. You should definitely enforce Password Must Meet Complexity Requirements.

Sunday, August 9, 2009

Lec 3: Program Security

This chapter has covered development issues in computer security: the kinds and effects of security flaws, and in malicious code, and the techniques that can help to control threats. Malicious code receives a great deal of attention in the media; the colorful terminology certainly draws people to stories about it, and the large numbers of affected systems ensure that major malicious code attacks get very wide visibility. But it is important for us to realize that the seriousness of the threat and the degree of vulnerability should also cause people to pay attention.

The total amount of damage already done is not measurable, but it is certainly large. Many successful attacks go undetected—for now, at least. With the explosive growth in connectivity to massive public networks such as the Internet, the exposure to threats is increasing dramatically. Yet the public continues to increase its reliance on computers and networks, ignoring the obvious danger.

In this chapter, we considered two general classes of security flaws: those that compromise or change data and those that affect computer service. There are essentially three controls on such activities: development controls, operating system controls, and administrative controls. Development controls limit software development activities, making it harder for a developer to create malicious programs. These same controls are effective against inadvertent mistakes made by developers. The operating system provides some degree of control by limiting access to computing system objects.


Finally, administrative controls limit the kinds of actions people can take. These controls are important for more than simply the actions they prohibit. They have significant positive effects that contribute to the overall quality of a system, from the points of view of developer, maintainer, and user. Program controls help produce better software. Operating systems limit access as a way of promoting the safe sharing of information among programs. And administrative controls and standards improve system usability, reusability, and maintainability.

For all of them, the security features are a secondary but important aspect of the controls' goals. Program controls are part of the more general problem of limiting the effect of one user on another. In the next chapter, we consider the role of the operating system in regulating user interaction

Saturday, July 25, 2009

Lab 2: The Goals of Information Technology

This Lab discusses resource security using NTFS permissions. It specifically discusses security on files and folders within the NT File System (NFTS). The Lab covers NTFS file and folder permissions, access control lists, using NTFS permissions,

Step 1 : Click on the Start button, then select the "Run" command. This will open a small box with a text field. In this field, type 'cmd' without the quotes and press enter.

Step 2 : At the resulting prompt, type in: chkntfs /d: [Enter]
If the message show “D: is not dirty”. This means that there is no corruption on the drive.

Step 3 : Now that we're in the command console, you'll need to enter in the command that will convert the drives. Make sure you type in the command exactly as it's shown (replace 'X:' with the drive letter you need to convert: CONVERT X: /FS:NTFS [Enter]

Step 4 : Close all Windows and log off


Data Confidentiality.

Use NTFS permissions to specify which users and groups can gain access to files and folders, and what they can do with the contents of the file or folder. NTFS permissions are only available on NTFS volumes. The permissions you assign for folders are different from the permissions you assign for files.
You assign folder permissions to control the access that users have to folders and to the files and subfolders that are contained within the folder.

Step 1 : Select Start >>Programs>>Administrative Tools >> Computer Managment
Step 2 : Choose >>Local User and Groups and double clickon the "user" folder.

Step 3 : Create the New User account by selecting User>>New User. The New User dialog box appears.
Step 4 : Complete these fields in the New User dialog box:
a. In the Username field, enter OpenView.
b. In the Full Name field, enter OpenView Administration.
c. In the Description field, enter Permit operation from OpenView services.
d. In the Password field, enter your password.
e. In the Confirm Password field, re-enter your password
f. Click button [Create]

_______________________________________________________________________

Creating data Confidentiality between 2 user accounts.
Step 1 : Log on to the Windows 2003 server as Administrator.
Step 2 : Create a new folder called Confidentiality.
Step 3 : In F0lder Confidentiality, crate another new folder called User1Folder
Step 4 : Right-click User1Folder >>[Properties] >> open the User1Folder Properties
Step 5 :Right-click the file or folder for which you want to assign permissions, In the Security tab

Step 6: Click on the Advanced Button

Step 7 : To add permissions to user accounts or groups for the folder, click Add

Step 9 : Uncheck the box “Allow inheritable permissions from parent to propagate to this object”.

Step 10 : Click [Copy] to retain the permissions.

Step 11 : Click [Add] and the Select Users, Computers, or Groups.Step

Step 12 :Type User1 and then click [Checks Names] and click OK


Step 13 : click the Allow Full Control box and then click OK for Permission Entry windows, .
Step 14: Remove the other username except Administrator, System and User1 by clicking the username

Step 15 : Click OK and Double-click User1Folder and you should see the content of the folder
Step 16 : All windows and log off close
Step 17 : Log on as User2 and navigate to the User1Folder, try to open this folder
Step 18 : Close all windows and log off.

Assigning Special Permissions
The standard NTFS permissions generally provide all of the access control that you need to secure your resources. However, there are instances in which the standard NTFS permissions do not provide the specific level of access that you may want to assign to users. To create a specific level of access, you can assign NTFS special permissions. This lesson introduces the NTFS special permissions. It then outlines the requirements and procedures for taking ownership of a folder or file.

Special permissions are set on the Permission Entry For dialog box for the file or folder. This dialog box is accessed by selecting Advanced on the Security tab of the Properties dialog box for the file or folder, and then selecting View/Edit for a Permission Entry on the Access Control Setting For dialog box for the file or folder.

Friday, July 24, 2009

Lec 2: Authentication & Basic Cryptography

All people must have authentication for identification allows one party (the verifier) to gain
assurances that the identity of another (the claimant) is as declared, thereby preventing impersonation. The most common technique is by the verifier checking the correctness of a message (possibly in response to an earlier message) which demonstrates that the claimant is in possession of a secret associated by design with the genuine party. Techniques which provide both entity authentication and key establishment are often integrated, Other names: entity authentication, identity verification



Cryptography to increase privacy:

There are two basic methods for data encryption:
- Symmetric key cryptographydata is encrypted and decrypted with the same key. the strength of encryption depends on the size of the key: a key with less than 40 bits is to be considered insecure, while a key with more than 128 bits is fairly unbreakable.the problem is: how get both parties the secret key in the first place


-Public key cryptographypublic key cryptography requires two keys, a secret ("private") key and a well known ("public") key. there are two different scenarios where public key cryptography may be used:
1. Send a secret message that only a particular receiver shall be able to read:the sender encrypt the message with the receiver's public key, only the holder of the corresponding private key can decrypt an read the message.
2. Digital signatures:the author of a document encrypts the text with his private key. anyone who knows the authors public key can decrypt and read the message, this reliably authenticates the author.

Saturday, July 18, 2009

Lab 1: Introduction to Virtualization & VMware

Today i would like tho share information about VIRTUALIZATION & VMware. Firtly you should be to know what is the virtualiztion? Virtualization is a proven software technology that is rapidly transforming the IT landscape and fundamentally changing the way that people compute. Virtualization lets you run multiple virtual machines on a single physica machine, sharing the resources of that single computer across multiple environments. Different virtual machines can run different operating systems and multiple applications on the same physical computer


WHAT IS VIRTUAL MACHINE?
A virtual machine (VM) is an environment usually a program or operting system, which does not physically exist but is created within another environment. In this context, a VM is called a "guest" while the environment it runs within is called a "host" while the environment it runs within is called a "host." Virtual machines are often created to execute an instruction set different than that of the host environment


VMware Workstation Installation.

VMware Workstation Can be Downloaded from
http://www.vmware.com/download/ws/

1. Double Click on the VMware launcher to start the installation Wizards

2. Click on [Next].

3. Choose Typical setup type
4. Choose the location for VMware Workstation installation, example: C:\Program

Files\WMware\VMware Workstation\, Click on [Next].

5. Configure the shortcuts for the VMware Workstation and click [Next].
6. Click on [Install], this will take several minutes to finish


7. Enter the Serial Number for the VMware workstation.


8. Click [Finish], and restart the Computer.



VMware

VMware Workstation makes it possible for PC user to use Multiple Operating Systems. Concurrently on the Same PC. User can create and run multiple virtual machine on desktop or laptop computer. VMware Workstation let you create a virtual machine that can be installed with different kinds of Operating System. Each virtual machine virtualized a complete set of PC, including Memory, HDD, network connections, peripheral ports and processor.



Creating Disk Image

1. From the home tab click on [New Virtual Machine], to open the virtual machine wizard

2. Click [Next] to continue.
3. Choose the typical configuration, click [Next]
4. Choose the type of OS to be installed on the virtual machine. As the next task the virtual machine
will be installed with Windows Server 2003, select [Microsoft Windows] as the guest. In the version list, select Windows Server 2003 Standard Edition. Click [Next]. Refer figure 1.10.

5. Name the virtual machine and specify the location where the disk image for the virtual machine
will be stored in the hard disk. Name the virtual machine as winserv03.

6. For the network type select [Use host-only Networking], this selection will create LAN between
the other virtual machine.In order to make the virtual machine connected to the real network select [Use bridged networking]. This setting can be changed once the virtual machine is created. Click[Next]. Refer figure 1.12.


7. Specify the disk capacity of the virtual machine. This option will let user to specify the maximum
storage capacity of the virtual machine. In this task set the storage capacity between 2GB to 4GB (Depends on the size of your PC). Select [Allocate disk space now] and click [Finish] to start creating your virtual



8. Once your disk image that holds you virtual machine is created you will see figure 1.14. Click [Close]


Get to know the virtual machine console.

Once the virtual machine is created, the tab will contain the home and summary view of winserv03 virtual machine
configuration. Refer figure1.15
.

Installing Windows Server 2003 on virtual machine.
1. Place the Windows Server 2003 installer CD in your cdrom drive
2. From the command menu click on [start the virtual machine] or you can click on the start button on the toolbar, your virtual machine is starting and will be booting from your cdrom drive. Refer figure 1.16 (a)



3. Once the winserv03 booting you will see the familiar windows server 2003 installatio page
from this point onward you can follow the windows server 2003 installation step.
4. After the installation process is finish, you will see the windows server 2003 login page.

5. Click on the console to start using the windows server 2003, to get the mouse pointer back to your host desktop, type CTRL + ALT on the keyboard.
6. You can try taking the snapshot of your OS by clicking on the [snapshot] button on the toolbar.If anything happened to your OS you can simply click the [Revert] button and choose your previous state.
7. You can also manage the size of your console screen by click on the [Quick switch] and [Full Screen] view option button on the toolbar.

Lec 1: Introduction to information security

Today we learn about why we must be learn a computer security, introduction to information in this topic we must know what is security, security architecture, Security Principles, Security Policy, SecurityAttacks / Threats, Methods of Defense, Security Service and Security Mechanisms

First we must know the meaning of IT security? The concept of IT security is of quality or state of being secure that is to be free from danger and to be protected from adversaries from those who would do harm, intentionally or otherwise. Besides, we must know the the type of security area, the type of security area is security architecture, security principles, security policy, and security attacks/ threats.


Example of Active Attacks





Example Of Passive Attacks



In the security area it consist a detection, prevention and recovery, each one have a own thier tools, for the security architecture, we must know defined by ITU-T Recommendation X.800 that called OSI Security Architecture, and we should be focus on security attacks, security mechanisms and security services.

In security principles its have confidentiality, integrity and availability, each part have a thier own function. Then we shoud be too know the security policy, security policy is set of rules to apply to security relevant activities in a security domain. There are two type of security attack, passive attack and active attack. In passive attack, it just monitor the transmission without modify. And the active attack, involve some modification of the data stream or the creation of a false stream.

Method of defense devided 6 part, it is Controls, Software Controls, Hardware Controls, Policies & Procedure Controls, Encryption Controls, Effectiveness of Controls, for to security services have 2 part, Defined by X.800 and Defined by RFC 2828. We too learn about the Categories Security Services, in the security services devided a data integrity, data confidentiality, access control, authentication, and nonrepudiation

And the last topic is Security Mechanisms. What is the Security Mechanisms? Security Mechanisms any process (or a device incorporating such a process) that is designed to detect, prevent or recover from a security attack and the specific of the security mechanisms is ExcAuthentication, Data Integrity, Encipherment, Digital Signature, Notarization, Routing Control, Trusted Functionality