Computer And Internet Security Pdf
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Cyber security is the practice of defending computers, servers, mobile devices, electronic systems, networks, and data from malicious attacks. It's also known as information technology security or electronic information security. The term applies in a variety of contexts, from business to mobile computing, and can be divided into a few common categories.
COMPUTER AND NETWORK SECURITY
Once the attacker has been authorized for entry, they may have full access to the organization's critical data, and depending on the privilege level they pretend to have may be able to modify and delete software and data, and make changes to network configuration and routing information. The unwitting consumer who purchases the software becomes, in a sense, a target-in-waiting for a crack attack.
Moreover, back doors tend to evade logging procedures; thus, even though every incoming connection to a system is supposedly logged, chances are that the back door provides a means of logging in without being logged.
Finally, back doors are covert in the real sense that they hide well. Even if the system administrator scans a system looking for suspicious software, chances are the back door has used techniques capable of missing the scan. A logic bomb works similar to a time bomb because it can be set to go off at a specific date. A logic bomb does not distribute malicious codes until the specified date is reached. Why Logic Bombs used? Other than targeting a specific computer or network system, a logic bomb can also be used to demand money for software by creating a code that makes the software application into a trial version.
After a specific period of time the user must pay a specified sum of money to continue to use the software. For this reason, logic bombs are usually targeted to specific victims and will not spread to unintended victims. The risk grows even larger in social media such as Facebook, Twitter, Myspace etc. Databases are central to modern websites. Web applications and databases allow you to regularly run your business.
A server has limited resources. They refer to listening to a conversation. Using this information, a network manager can keep traffic flowing efficiently. A network router reads every packet of data passed to it, determining whether it is intended for a destination within the router's own network or whether it should be passed further along the Internet. Sniffers are often used on academic networks to prevent traffic bottlenecks caused by file-sharing applications.
For example, a database could be analyzed for certain kinds of duplication. The intention is to consume the limited memory set aside in the switch to store the MAC address table.
It is typically used in a scenario where you generate network packets that say they originated by computer B while they really originated by computer C. Spoofing in an email context means sending an email pretending to be someone else. Spam and phishing emails typically use such spoofing to mislead the recipient about the origin of the message. Although their use is increasing, it is likely that almost half of all domains still do not have such measures in place.
Spoofing has both legal uses and illegitimate uses such as impersonating another person, company, product. Password ProtectionThe front line of defense against intruders is the password system. Virtually all multiuser systems require that a user provide not only a name but also a password. The password serves to authenticate the ID of the individual logging on to the system. In turn, the ID provides security in the following ways The ID determines whether the user is authorized to gain access to a system.
The ID determines the privileges accorded to the user. This practice generally refers to software vulnerabilities in computing systems. The DES algorithm is modified using a bit. If the encrypted password portion of the file is accessible only by a privileged user, then the opponent cannot read it without already knowing the password of a privileged user. They store encrypted copies of all your sites. You just need a single strong password to get any other password. The argument is what happens when they get hacked, or you have a key logger on your machine?
A variation of this is your browser's ability to remember passwords, which is a very bad idea. Most browsers have an option to show you your password in plain text. Someone can walk up to your computer and look right through your passwords. If you are going to use a password manager, at least use a third-party product. Password Selection Strategies The password list or book where you keep site names and passwords:The argument against this is losing the book.
You can easily solve the issue by using a short hand in your notes. Instead of writing theabcxyz. You know that tax means the abcxyz, but would the person who picked up your book know?
That depends on if they know you, or they found it laying somewhere Password Selection Strategies Your brain and a system:This is the password sandwich. This is where you create a short ingredient list. Preferably, two weak ingredients the bread , and one stronger ingredient the main ingredient is used.
You connect them with special characters condiments. The system part is how you assemble it. First, We recommend one piece of bread be a site code such as tax for theabcxyz. Second we recommend an expiration code for the other piece of bread such as q2 for expires second quarter. For the main ingredient we recommend mnemonics of short rhythmic phrases.
Use a song you cannot get out of your head. Putting it together, theabcxyz becomes tax TbmShtr! You can write these all down using a shorthand on a simple wallet card using your own shorthand. Password Selection Strategies The password hasher:This runs a weak password through an algorithm using the site name as a seed. The best known of these is the Stanford Pwdhash.
This is a simple tool that you enter the site address and a password. It then creates a more complex hashed password from it. For example, I used thebcxyz. If you choose your characters wisely, you can make stronger passwords using fewer characters. A character is any letter, number, or punctuation mark. When selecting special characters, try to use ones that are comfortable for you to type. It is frustrating to find your device does not support the special character you used in a great password.
One of the first things cracking programs do is try "password". Shortly after they try "drowssap" password spelled backward. Permission to access a resource is called authorization. The most common biometric access systems use fingerprints, but these systems can also use retinal scans, hand geometry, and facial recognition technology.
These pictures are then processed into digital templates that contain the unique extracted features of a finger. Instead of typing a password, users place a finger on an electronic scanner. The scanner, or reader, compares the live fingerprint to the fingerprint template stored in a database to determine the identity and validity of the person requesting access.
Full hand geometry systems take an image of the entire hand for comparison while Two Finger readers only image two fingers of the hand. The graph of the hand is extracted, and some geometrical characteristics stored. How is voice recognition performed? The program contains the input template, and attempts to match this template with the actual input using a simple conditional statement. The goal of voice recognition systems is simply to understand the spoken word, not to establish the identity of the speaker.
Preprocess the raw data of the given signature. Extract features and compare distances with the those in the template. Make decision according to the threshold specified in the template. Only X-coordinates can not distinguish them! Symmetric encryption also referred to as conventional encryption or single-key encryption.
The key is a value independent of the plaintext and of the algorithm. It depends on the plaintext and the secret key. For a given message, two different keys will produce two different ciphertexts. The ciphertext is an apparently random stream of data and, as it stands, is unintelligible. It takes the cipher text and the secret key and produces the original Plaintext.
COMPUTER AND NETWORK SECURITY
Network security combines multiple layers of defenses at the edge and in the network. Particular attention is paid to congestion; other special topics include queuing, real-time traffic, network management, security and the ns simulator. Computer Network Security Fundamentals. Many cyber security threats are largely avoidable. Users also are responsible for bringing all known information security vulnerabilities and violations that they notice to the attention of the Information Technology department.
What is Cyber Security?
Free download Read online. Fully revised and updated, this timely new edition encompasses the latest developments in system resource virtualization, cloud computing models, and mobile computing technology, including a new chapter on the Internet of Things.
The scale of the cyber threat
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У нее был такой вид, словно она только что увидела призрак. - Джабба! - Соши задыхалась. - Червь… я знаю, на что он запрограммирован! - Она сунула распечатку Джаббе. - Я поняла это, сделав пробу системных функций. Мы выделили отдаваемые им команды - смотрите.
- Бринкерхофф присвистнул. - Я и понятия не имел. - Его глаза сузились. - Так к чему ты клонишь. - Я думаю, что Стратмор сегодня воспользовался этим переключателем… для работы над файлом, который отвергла программа Сквозь строй. - Ну и. Для того и предназначен этот переключатель, верно.
В обычных обстоятельствах это насторожило бы Стратмора, но ведь он прочитал электронную почту Танкадо, а там говорилось, что весь трюк и заключался в линейной мутации. Решив, что никакой опасности нет, Стратмор запустил файл, минуя фильтры программы Сквозь строй. Сьюзан едва могла говорить. - Никакой Цифровой крепости не существует, - еле слышно пробормотала она под завывание сирены и, обессилев, склонилась над своим компьютером. Танкадо использовал наживку для дурачков… и АНБ ее проглотило.
Лицо его было несчастным. - Я думал, вы из городского… хотите заставить меня… - Он замолчал и как-то странно посмотрел на Беккера. - Если не по поводу колонки, то зачем вы пришли.
Когда он перевернул ее на спину и взгромоздился сверху, она подумала, что сейчас он ее раздавит. Его массивная шея зажала ей рот, и Росио чуть не задохнулась. Боже, поскорей бы все это закончилось, взмолилась она про .