Internet: Protocols, History, Services, and Security

Posted on Dec 8, 2024 in Computers

Internet

The Internet is a worldwide network consisting of devices that communicate with each other using a language called a protocol. The primary purpose of this protocol is the exchange of information.

What do we need to use the Internet?

  • Computer
  • Internet: A software tool that lets you view web pages (service provider ISP).
  • Browser
  • Modem or Router:
    • Modem: A modulator and demodulator which is responsible for converting digital signals to analog and vice versa.
    • Router: A device responsible for determining the path information should take to be transmitted over networks, i.e., it distributes traffic.

Protocols

A communication protocol is a set of rules that allows devices to communicate with each other.

  • PPP: The Point-to-Point Protocol is used for modem connections through telephone lines.
  • TCP/IP: The Transfer Control Protocol/Internet Protocol works by packet transmission. The information sent is divided into fragments at the source with a specific destination, and it travels between computers over networks.

Internet History

Between 1950 and 1970, a project was launched to create computer networks that would allow secure and fixed information exchange between different users. The largest project was funded by ARPANET, the U.S. Department of Defense, and therefore had a clear military objective. This became possible in 1973 when the first connections were made between the U.S., England, and Norway.

Internet Services

Web Browsing

To access a home page, you must know its URL. The URL is unique. To use web browsing, it is necessary to have the corresponding software, called a browser.

Email

You can receive and send mail from anywhere in the world through email servers. This service can be free or paid. You can send anything from text to graphics. For sending mail, the protocol (SMTP) is used, and for receiving mail, Pop3 is used.

Other Services

  • FTP: File Transfer Protocol allows file transfer between computers or uploading/downloading to a server using the file transfer protocol.
  • Instant Messaging
  • Forum: Allows a user group to read and write on different topics. It is not in real-time.
  • Chat: These are in real-time. Only users connected at that time can see the messages.
  • Newsgroup: Allows a user group to read and send text messages about a particular topic.
  • Telephony Service: Allows voice conversations between two users.
  • Telnet Service: It is a remote connection protocol that uses a client and a server for a connection.

Internet Security

A secure system is similar to a reliable system in that it behaves as expected, but it does not reach the level of never failing.

  • Confidentiality: Prevents unauthorized users from accessing private information.
  • Access Control: Prevents unauthorized users from accessing system resources for which they do not have the necessary permissions.
  • Integrity: Prevents the alteration or modification of information by unauthorized users during communication.
  • Authentication: Ensures the identity of users involved in a data link.

Types of Attacks

  • Interruption: An attack on availability, as it implies that information is not available due to loss or modification.
  • Interception: An attack on confidentiality in which an unauthorized user gains access to private information transmitted between authorized users.
  • Modification: An attack on integrity where an unauthorized user gains access to private information and modifies it.
  • Fabrication: An attack on integrity similar to modification. An unauthorized user impersonates an authority and creates information similar to that which is programmed. This information is sent to the authorized user, who believes they are receiving legitimate information.

Internet Risks

  • Backdoors: Authentication shortcuts created by programmers during program development and retained afterward.
  • Logic Bombs: These are a type of malware inserted into a program as a code snippet that is triggered by some action, damaging the system.
  • Virus: Another type of malware, these are codes included in executable files. When the file is run, the virus also becomes operational.
  • Worms: A type of malware consisting of programs that run and spread across networks, exploiting security holes in the system.
  • Trojans: A type of malware with a hidden agenda within another program. When the program is run, the Trojan also runs.

Cryptography

  • Symmetric Cryptography (Secret Key or Simple): Uses a single key to encrypt or decrypt information.
  • Asymmetric Cryptography (Public Key): Uses one key for encryption (public key) and another for decryption (private key). Everyone has access to the public key, while only the user knows the private key.

HTTP and HTTPS

  • HTTP: Used for communication between the server and browser.
  • HTTPS: The secure version of the protocol, encrypting communication between the client and server using digital certificates.

Digital Certificate

The digital certificate guarantees the security of transmissions. Digital certificates are unique and fully identify a user. This certificate is internationally recognized. These identification documents are provided by certification authorities (such as national currency and stamp offices). This certifies that the user is who they claim to be. To obtain this certificate, a document containing the necessary data must be completed. To verify certification, the user only needs to double-click on the padlock. Finally, there are different types of certificates, with class zero certificates being the most readily available and requiring the least amount of data.