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    (Wikipedia) - Internet security
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    Internet security is a tree branch of computer security specifically related to the Internet, often involving browser security but also network security on a more general level as it applies to other applications or operating systems on a whole. Its objective is to establish rules and measures to use against attacks over the Internet. The Internet represents an insecure channel for exchanging information leading to a high risk of intrusion or fraud, such as phishing. Different methods have been used to protect the transfer of data, including encryption.

    • 1 Types of security
      • 1.1 Network layer security
      • 1.2 Internet Protocol Security (IPsec)
      • 1.3 Security token
      • 1.4 Electronic mail security (E-mail)
        • 1.4.1 Background
        • 1.4.2 Pretty Good Privacy (PGP)
        • 1.4.3 Multipurpose Internet Mail Extensions (MIME)
        • 1.4.4 Message Authentication Code
    • 2 Firewalls
      • 2.1 Role of firewalls in web security
      • 2.2 Types of firewalls
        • 2.2.1 Packet filter
        • 2.2.2 Stateful packet inspection
        • 2.2.3 Application-level gateway
    • 3 Malicious software
      • 3.1 Malware
        • 3.1.1 Viruses
        • 3.1.2 Worms
        • 3.1.3 Trojan horse
        • 3.1.4 Ransomware and Scareware
        • 3.1.5 Botnet
        • 3.1.6 Spyware
    • 4 Denial-of-service attack
    • 5 Browser choice
    • 6 Application vulnerabilities
    • 7 Internet security products
      • 7.1 Antivirus
      • 7.2 Security Suites
    • 8 See also
    • 9 References
    • 10 External links

    Types of security Network layer security

    TCP/IP which stands for Transmission Control Protocol (TCP) and Internet Protocol (IP) aka Internet protocol suite can be made secure with the help of cryptographic methods and protocols. These protocols include Secure Sockets Layer (SSL), succeeded by Transport Layer Security (TLS) for web traffic, Pretty Good Privacy (PGP) for email, and IPsec for the network layer security.

    Internet Protocol Security (IPsec) Main article: IPsec

    This protocol is designed to protect communication in a secure manner using TCP/IP aka Internet protocol suite. It is a set of security extensions developed by the Internet Task force IETF, and it provides security and authentication at the IP layer by transforming data using encryption. Two main types of transformation that form the basis of IPsec: the Authentication Header (AH) and ESP. These two protocols provide data integrity, data origin authentication, and anti-replay service. These protocols can be used alone or in combination to provide the desired set of security services for the Internet Protocol (IP) layer.

    The basic components of the IPsec security architecture are described in terms of the following functionalities:

    • Security protocols for AH and ESP
    • Security association for policy management and traffic processing
    • Manual and automatic key management for the internet key exchange (IKE)
    • Algorithms for authentication and encryption

    The set of security services provided at the IP layer includes access control, data origin integrity, protection against replays, and confidentiality. The algorithm allows these sets to work independently without affecting other parts of the implementation. The IPsec implementation is operated in a host or security gateway environment giving protection to IP traffic.

    Security token

    Some online sites offer customers the ability to use a six-digit code which randomly changes every 30–60 seconds on a security token. The keys on the security token have built in mathematical computations and manipulate numbers based on the current time built into the device. This means that every thirty seconds there is only a certain array of numbers possible which would be correct to validate access to the online account. The website that the user is logging into would be made aware of that devices'' serial number and would know the computation and correct time built into the device to verify that the number given is indeed one of the handful of six-digit numbers that works in that given 30-60 second cycle. After 30–60 seconds the device will present a new random six-digit number which can log into the website.

    Electronic mail security (E-mail) Background See also: Electronic mail

    Email messages are composed, delivered, and stored in a multiple step process, which starts with the message''s composition. When the user finishes composing the message and sends it, the message is transformed into a standard format: an RFC 2822 formatted message. Afterwards, the message can be transmitted. Using a network connection, the mail client, referred to as a mail user agent (MUA), connects to a mail transfer agent (MTA) operating on the mail server. The mail client then provides the sender’s identity to the server. Next, using the mail server commands, the client sends the recipient list to the mail server. The client then supplies the message. Once the mail server receives and processes the message, several events occur: recipient server identification, connection establishment, and message transmission. Using Domain Name System (DNS) services, the sender’s mail server determines the mail server(s) for the recipient(s). Then, the server opens up a connection(s) to the recipient mail server(s) and sends the message employing a process similar to that used by the originating client, delivering the message to the recipient(s).

    Pretty Good Privacy (PGP)

    Pretty Good Privacy provides confidentiality by encrypting messages to be transmitted or data files to be stored using an encryption algorithm such Triple DES or CAST-128. Email messages can be protected by using cryptography in various ways, such as the following:

    • Signing an email message to ensure its integrity and confirm the identity of its sender.
    • Encrypting the body of an email message to ensure its confidentiality.
    • Encrypting the communications between mail servers to protect the confidentiality of both message body and message header.

    The first two methods, message signing and message body encryption, are often used together; however, encrypting the transmissions between mail servers is typically used only when two organizations want to protect emails regularly sent between each other. For example, the organizations could establish a virtual private network (VPN) to encrypt the communications between their mail servers over the Internet. Unlike methods that can only encrypt a message body, a VPN can encrypt entire messages, including email header information such as senders, recipients, and subjects. In some cases, organizations may need to protect header information. However, a VPN solution alone cannot provide a message signing mechanism, nor can it provide protection for email messages along the entire route from sender to recipient.

    Multipurpose Internet Mail Extensions (MIME)

    MIME transforms non-ASCII data at the sender''s site to Network Virtual Terminal (NVT) ASCII data and delivers it to client''s Simple Mail Transfer Protocol (SMTP) to be sent through the Internet. The server SMTP at the receiver''s side receives the NVT ASCII data and delivers it to MIME to be transformed back to the original non-ASCII data.

    Message Authentication Code

    A Message authentication code (MAC) is a cryptography method that uses a secret key to encrypt a message. This method outputs a MAC value that can be decrypted by the receiver, using the same secret key used by the sender. The Message Authentication Code protects both a message''s data integrity as well as its authenticity.


    A computer firewall controls access between networks. It generally consists of gateways and filters which vary from one firewall to another. Firewalls also screen network traffic and are able to block traffic that is dangerous. Firewalls act as the intermediate server between SMTP and Hypertext Transfer Protocol (HTTP) connections.

    Role of firewalls in web security

    Firewalls impose restrictions on incoming and outgoing Network packets to and from private networks. Incoming or outgoing traffic must pass through the firewall; only authorized traffic is allowed to pass through it. Firewalls create checkpoints between an internal private network and the public Internet, also known as choke points(borrowed from the identical military term of a combat limiting geographical feature). Firewalls can create choke points based on IP source and TCP port number. They can also serve as the platform for IPsec. Using tunnel mode capability, firewall can be used to implement VPNs. Firewalls can also limit network exposure by hiding the internal network system and information from the public Internet.

    Types of firewalls Packet filter Main article: firewall (computing)

    A packet filter is a first generation firewall that processes network traffic on a packet-by-packet basis. Its main job is to filter traffic from a remote IP host, so a router is needed to connect the internal network to the Internet. The router is known as a screening router, which screens packets leaving and entering the network.

    Stateful packet inspection Main article: circuit-level gateway

    In a stateful firewall the circuit-level gateway is a proxy server that operates at the network level of an Open Systems Interconnection (OSI) model and statically defines what traffic will be allowed. Circuit proxies will forward Network packets (formatted unit of data ) containing a given port number, if the port is permitted by the algorithm. The main advantage of a proxy server is its ability to provide Network Address Translation (NAT), which can hide the user''s IP address from the Internet, effectively protecting all internal information from the Internet.

    Application-level gateway Main article: application-level gateway

    An application-level firewall is a third generation firewall where a proxy server operates at the very top of the OSI model, the IP suite application level. A network packet is forwarded only if a connection is established using a known protocol. Application-level gateways are notable for analyzing entire messages rather than individual packets of data when the data are being sent or received.1

    Malicious software Malware Main article: Malware

    A computer user can be tricked or forced into downloading software onto a computer that is of malicious intent. Such programs are known as malware and come in many forms, such as viruses, Trojan horses, spyware, and worms. Malicious software is sometimes used to form botnets.

    Viruses Main article: Computer virus

    Computer Viruses are programs that can replicate their structures or effects by infecting other files or structures on a computer. The common use of a virus is to take over a computer to steal data.

    Worms Main article: Computer worm

    Computer worms are programs that can replicate themselves throughout a computer network, performing malicious tasks throughout.

    Trojan horse Main article: Trojan horse (computing)

    A Trojan horse commonly known as a Trojan is a general term for malicious software that pretends to be harmless, so that a user willingly allows it to be downloaded onto the computer.

    Ransomware and Scareware Main articles: Ransomware (malware) and Scareware Botnet Main article: Botnet

    A botnet is a network of zombie computers that have been taken over by a robot or bot that performs large-scale malicious acts for the creator of the botnet.

    Spyware Main article: Spyware

    The term spyware refers to programs that surreptitiously monitor activity on a computer system and report that information to others without the user''s consent.

    Denial-of-service attack For more details on this topic, see Denial-of-service attack.

    A denial-of-service attack (DoS attack) or distributed denial-of-service attack (DDoS attack) is an attempt to make a computer resource unavailable to its intended users. Although the means to carry out, motives for, and targets of a DoS attack may vary, it generally consists of the concerted efforts to prevent an Internet site or service from functioning efficiently or at all, temporarily or indefinitely.

    Browser choice Main article: Browser security

    Web browser statistics tend to affect the amount a Web browser is exploited. For example, Internet Explorer 6, which used to own a majority of the Web browser market share, is considered extremely insecure because vulnerabilities were exploited due to its former popularity. Since browser choice is more evenly distributed (Internet Explorer at 28.5%, Firefox at 18.4%, Google Chrome at 40.8%, and so on) and vulnerabilities are exploited in many different browsers.

    Application vulnerabilities Main article: Application security

    Applications used to access Internet resources may contain security vulnerabilities such as memory safety bugs or flawed authentication checks. The most severe of these bugs can give network attackers full control over the computer. Most security applications and suites are incapable of adequate defense against these kinds of attacks.

    Internet security products Antivirus Main article: Antivirus

    Antivirus and Internet security programs can protect a programmable device from malware by detecting and eliminating viruses; Before 2000 a user would pay for antivirus software, 10 years later however, computer users can choose from a host of free security applications on the Internet.

    Security Suites

    So called "security suites" were first offered for sale in 2003 (McAffee) and contain a suite of firewalls, anti-virus, anti-spyware and more. They may now offer theft protection, portable storage device safety check, private internet browsing, cloud anti-spam, a file shredder or make security-related decisions (answering popup windows) and several were free of charge as of at least 2012.

    Tags:Computer, Computer virus, Denial-of-service attack, Domain, Firefox, Google, Google Chrome, HTTP, Hypertext, Hypertext Transfer Protocol, Internet, Internet Explorer, Internet protocol suite, Internet security, Malware, Transport Layer Security, Wikipedia

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