Showing posts with label Computer Security System. Show all posts
Showing posts with label Computer Security System. Show all posts

Software for Internet Security

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Stay alert at all times about your security software. Make sure each day that is updated properly and do not face any problems when updating. If so, check with the particular software company immediately, since a slight ignorance of his face could only lead to great results devastating. A more frequent automatic update could mean that the number of threats to their growing team. Always put the computer in the automatic update. This allows you to download all the latest updates available, even if you forget to check out someday.

If you're new computer, make sure you've done your homework. Make a thorough research on the internet software and the best security available, install it on your computer.

Stay alert while remaining connected to the Internet. Keep an eagle eye on their updates Internet security software and any virus or spyware. Get the software of the elite class that I do not regret later when you stay with contaminated equipment. You can search online or ask for views on public discussion forums. You can also buy computer magazines and look up to the latest security software and best of the Internet. The software also will be available in certain stores. However, the online software download would be a much easier job.

Therefore, we must take all the above points in mind when making the choice for Internet security software, because the security of your computer along with your personal information is very important. No one should have access to them by any means.

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Complexity of Substitution Encryption and Decryption

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An important issue in using any cryptosystem is the time it takes to turn plaintext into ciphertext, and vice versa. Especially in the field it is essential that the scrambling and unscrambling do not deter the authorized parties from completing their missions. The timing is directly related to the complexity of the encryption algorithm. For example encryption and decryption with substation ciphers can be performed by direct lookup in a table illustrating the correspondence, like the ones shown in example. One way thinking of this expression is that if one message is twice as long as another, it will take twice as long to encrypt.

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Substitution Ciphers of Computing System

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Children sometimes devise ‘secret codes’ that use a correspondence table with which to substitute a character or symbol for each character of the original message. This technique is called a monoalphabetic cipher or simple substitution, A substitution is an acceptance way of encryption text. Read More


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Cryptanalysis in security system

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A cryptanalysts chore is to break an encryption. That is the cryptanalyst attempts to m, deduce the original meaning of a ciphertext message. Better yet, he or she hopes to determine which decrypting algorithm matches the encrypting algorithm, so that other message encoded in the same way can be broken. Thus a cryptanalyst can do any or all of six different things-

Attempt to break a single message

Attempt to recognize patterns in encrypted messages, to be able to break subsequent ones by applying a straightforward decryption algorithm

Attempt to infer some meaning without even breaking the encryption, such as noticing an unusual frequency of communication or determining something by whether the communication was short or long.

Attempt to deduce the key in order to break subsequent message easily

Attempt to find weaknesses in the implementation or environment of use of encryption.

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Terminology process

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Encryption is the process of encoding a message so that its meaning is not obvious. Decryption is the reverse process, transforming an encrypted message back into its normal, original form. Alternatively the terms encode and decode or encipher and decipher are used instead of encrypt and decrypt. That is we say that we encode encrypt or encipher the original message to hide its meaning. Then we decode, decrypt or decipher it to reveal the original message. A system for encryption and decryption is called a cryptosystem.


The original form of a message is known as plaintext, and the encrypted form is called cipher text. For convenience in explanation, we denote a plaintext message p as a sequence of individual characters p={p1, p2, …..pn}. Similarly cipher text is written as C={c1, c2,…..cm}. for instance, the plaintext message “ I want cookies” can be through  of as the message string { I, w ,a, n, t, c, o, o, k, I, e, s}. it may be transformed into cipher text { c1, c2, ……c14} and the encryption algorithm tells us how the transformation is done.            

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Controls in security system

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To consider the controls or countermeasures that attempts to prevent exploiting computing system vulnerabilities, we begin by thinking about traditional ways to enhance physical security. In the middle ages, castles and fortresses were built to protect the valuable people and property inside. The fortress might have had one or more security characteristics including-

  • A strong gate or door to repel invaders

  • Heavy walls to withstand objects thrown or projected against them

  • A surrounding moat, to control access

  • Arrow slits to let archers shoot at approaching enemies

   Read More 

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Career Criminals

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By contrast the career computer criminal understands the targets of computer crime. Criminals seldom change fields from arson or auto theft to computing more often criminals begin as computer professionals who engage in computer crime finding the prospects and payoff good. There is some evidence that organized crime and international groups are engaging in computer crime. Recently electronic spies and information brokers have begun to recognize that trading in companies or individuals secrets can be lucrative. 

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What is Amateurs?

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Amateurs have committed most of the computer crimes reported to date. Most embezzlers are not career criminals but rather are normal who observe a weakness in a y security system that allows them to access cash or other valuables. In the same sense computer criminals are ordinary computer professionals or users doing their jobs, when they discover they have access to something valuable. When no one objects the amateur may start using the computer at work to write letters maintain soccer league team standings or do accounting.  

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Computer Criminals

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Computer criminals are mean and sinister types. But many more wear business suits have university degrees, and appear to be pillars of their communities. Some are high schools or university students. Others are middle aged business executives. Some are mentally deranged, overtly hostile or extremely committed to a cause and they attack computers as a symbol.

Whatever their characteristics and motivations computer criminals have access to enormous amounts of hardware, software and data; they have the potential to cripple much of effective business and government throughout the world. In a sense then the purpose of computer security is to prevent these criminals from doing damage. Read More 

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Software Modification System

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Software is vulnerable to modifications that either cause it to fail or cause it to perform an unintended task. Indeed, because software is so susceptible to ‘off by one’ errors, it is quite easy to modify. Changing a bit or two can convert a working program into a failing one. Depending on which bit was changed, the program may crash when it begins, or it may execute for some time before it falters.

Other categories of software modification include:


A Trojan horse:  A Trojan horse is a program that overtly does one thing while covertly doing another.


A Virus:  A Virus is a specific type of Trojan horse that can be used to spread its ‘infection’ from one computer to another.


A Trapdoor:  A Trapdoor is a program that has a secret entry point.

Information leaks: Information leaks in a program: code that makes information accessible to unauthorized people or programs.  
     

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The meaning of vulnerability

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When we prepare to test a system we usually try to imagine how the system can fail, then we look for ways in which the requirements, design, or code can enable such failures. In the same way when we prepare to specify, design, code, or test a secure system, we try to imagine the vulnerabilities that would prevent us from reaching one or more of our three security goals. It is sometimes easier to consider vulnerabilities as they apply to all three broad categories of system resources, rather than to start with the security goals themselves. Read More     


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Security Goals

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We use the term security in many ways in our daily lives. A security system protects our house, warning the neighbors or the police if an unauthorized intruder tries to get in. Financial security involves a set of investments that are adequately funded: When we talk about computer security we mean that we are addressing three very important aspects of any computer related system- Confidentiality, integrity, and availability.


Confidentiality: It ensures that computer-related assets are accessed only by authorized parties. That is only those who should have access to something will actually get that access. By access we mean not only reading but also viewing, printing, or simply knowing that a particular asset exists. Confidentiality is sometimes called secrecy or privacy.


Integrity: It means that assets can be modified only by authorized parties or only in authorized ways. In this context modification includes writing, changing, changing status, deleting and creating.


Availability: Availability means that assets are accessible to authorized parties at appropriate times. In other words if some person or system has legitimate access to a particular set of objects, that access should not be prevented. For this reason availability is sometimes known by its opposite, denial of service.      

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Attacks in Computer System

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When you test any computer system, one of your jobs is to imagine how the system could malfunction. Then you improve the systems design so that the system can with stand any of the problems you have identified. In the same way, we analyze a system from a security perspective thinking about ways in which the systems security can malfunction and the value of its assets. Read More 

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Principle of Easiest Penetration

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An intruder must be expected to use any available means of penetration. The penetration may not necessary be by the most obvious means nor is it necessarily the one against which the most solid defense has been in stalled. This principle implies that computer security specialists must consider all possible means of penetration.
Moreover the penetration analysis must be done repeatedly and especially whenever the system and its security change. Strengthening one aspect of a system may simply make another means of penetration more appealing to intruders.  

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