computer network or data network is a telecommunications network that allows computers to exchange data. In computer networks, networked computing devices pass data to each other along data connections. The connections between nodes are  established using either cable media or wireless media. The best-known computer network is the Internet.

Some basics of computer networking :-

  • Network Security :- It refers to any activities designed to protect your network. These activities protect the usability, reliability, integrity and safety of your network and data. Network security consists of provision and policies adopted by network administrator to prevent and monitor unauthorized access, misuse, modification and denial of computer network and network accessible.
    Many network security threats are viruses, worms, trojan horse, data interception and theft, identity theft
    Network security components includes antivirus, antispyers, firewalls to block unauthorized access, virtual private networks.
  • Type of attacks :-
    1). Active attacks : An intruder initiates commands to disrupt the network normal operation eg: denial of service, man in the middle
    2). Passive attacks : When network intruder intercepts the data travelling through the network eg: wire tapping, port scanner.
  • Happy Birthday attack :- A birthday attack is a type of cryptography attack that exploit the mathematics behind the birthday problem in probability theory. This attack depends on the higher likelihood of collisions found between random attack attempts and a fixed degree of permutations (pigeonholes) as describe in birthday problem.
  • Message Digest :- The representation of text in the form of a single string of digits, created using a formula called a one way hash function, encryption a message digest with a private key creates a digital signature which is an electronic means of authentications.
  • Authentication :- Authentication is the process of determining the true identity of someone. Basic authentication is simply using a password to verify that you are who you say you are. More complicated and more precise methods bio-metrics such as figure print and retina scan.
  • Public key infrastructure : Public key is a system for the creation, storage and distribution of digital certificates which are used to verify that a particular public key belongs to a certain entity. It creates digital certificates which map public key to entities, securely and revoke them if needed.
    It is basically used to communicate securely on an insecure public network.
  • Cryptography :- It includes encryption and decryption of data. It helps to communicate securely on and insecure public network so that the information cannot be read by anyone expect the intended recipient
    Secure Key Cryptography : It uses a single key for both encryption and decryption
    Public Key Cryptography : It uses key for encryption and another for decryption.
  • Digital Signature :- It is a electronic encrypted stamp of authentication on digital information. A signature confirms that the information originated from the signer and has not been altered.
  • Digital Certificate :- It is an electronic document that uses a digital signature to bind a public key with an identity, The certificate can be used to verify that a public key belongs to an individual.
  • Hashing :- A hash function is any algorithm that maps data of variable length to data of a fixed length. Hashing is a way of securing information. It summarizes text into a short finger print that can’t be decrypted.
    Hash Function :- It uses a mathematical transformation to irreversibly encrypted information. It is a one way cryptography. Hash function have no key since the plain text is not recoverable from the ciphertext.