# Cryptography And Network Security 2021 | Full Explained with Example

Cryptography and Network Security: Cryptography is an automated mathematical tool that plays a vital role in network security. It assures the confidentiality and integrity of data as well as provides authentication and non-repudiation to the users.

## Cryptography and Network Security

Cryptography and Network security historically dealt with the creation and analysis of protocols that prevent any third party from reading a private communication between two parties. In the digital age, cryptography has evolved to address the encryption and decryption of private communications through the Internet and computer systems, an offshoot of cyber and network security, which was unlike anything seen in the world of cryptography before the advent. is far more complex computer.

## Importance in Cyber Security

The most basic use of computer cryptography is to scramble a piece of text and send it to a remote location on the Internet, where the data is unscrambled and delivered to the receiver. This is how computer cryptography and Network Security go hand in hand. Certificate Authorities (CAs) are responsible for passing digital certificates to validate ownership of the encryption key, which is used to secure communications based on trust. Let’s take a look at two popular forms of encryption used by cyber security experts:

### symmetrical

A symmetric encryption is used to create a file that can be encrypted and decrypted using the same key. Also known as ‘secret key’ encryption, it uses the same algorithm to decode a script as the algorithm used to encrypt it in the first place. This makes it easy to use keys to multiple sources because only one code needs to be learned, but it also means that there is only one line of defense against hackers who might be able to guess the code.

### asymmetric

On the other hand, ‘public key’ encryption uses a key that belongs to a select group of people who are able to use it to encrypt/decrypt data. Essentially, the protection of an encryption algorithm depends on more than one key. Two keys are often used in this system, one to encrypt the information and the other to decrypt it. While a higher number of keys does create some amount of confusion, it also makes the communication system more secure.

## What is cryptography in security?

Cryptography provides secure communication in the presence of malicious third-parties – known as adversaries. Encryption uses an algorithm and a key to convert an input (ie, plaintext) into an encrypted output (ie, ciphertext). A given algorithm will always convert the same plaintext to the same ciphertext if the same key is used.

The algorithm is considered secure if an attacker cannot determine the plaintext or any properties of the key by looking at the ciphertext. An attacker shouldn’t be able to determine anything about the key, given the large number of plaintext/ciphertext combinations that use the key.

## Types of cryptography

In general there are three types Of cryptography:

### Symmetric Key Cryptography:

It is an encryption system where the sender and receiver of the message use the same common key to encrypt and decrypt the messages. Symmetric key systems are fast and simple but the problem is that the sender and receiver have to exchange keys in some way in a secure way. The most popular symmetric key cryptography system is the Data Encryption System (DES).

### hash function:

No key is used in this algorithm. The fixed-length hash value is calculated according to the plain text making it impossible to retrieve the contents of the plain text. Many operating systems use hash functions to encrypt passwords.

### Asymmetric Key Cryptography:

Under this system a pair of keys is used to encrypt and decrypt the information. A public key is used for encryption and a private key is used for decryption. Public key and private key are different. Even if the public key is known by all, the intended receiver can only decode it because he alone knows the private key.

## Importance of cryptography in network security

Network administrators use a number of security mechanisms to protect the data in the network from unauthorized access and various threats. Security mechanisms increase the usability and integrity of the network. The design aspects of network security systems include both hardware and software technologies. Application domains of security systems cover both public and private computer networks that are used in everyday jobs to conduct transactions and communications between business partners, government agencies, enterprises and individuals.

Network security plans differ depending on the type of network, i.e. public or private, wired or wireless. Data security includes encryption, tokenization, and key management practices to protect data across all applications and platforms. Antivirus and antimalware software are also part of network security to protect against malware such as spyware, ransomware, Trojans, worms, and viruses. Cryptography is an automated mathematical tool that plays an important role in network security. It assures the confidentiality and integrity of the data as well as provides authentication and non-repudiation to the users. This chapter mainly focuses on cryptography techniques and their role in protecting network security.

Cryptography techniques include encryption and decryption algorithms. Encryption algorithms do the scrambling of simple text and generate an unreadable format for third parties called ciphertext. The original data is reconstituted by the intended receiver using decryption algorithms. Cryptographic techniques are broadly classified into three categories, namely symmetric-key cryptography, asymmetric-key cryptography, and authentication. Widely accepted cryptographic algorithms are outlined with their relative advantages and disadvantages. In addition, more recent efficient cryptographic algorithms specific to cloud computing, wireless sensor networks and on-chip-networks are thoroughly discussed that provide a clear view of how to achieve secure communications across networks using cryptography.

## What is the difference between network security and cryptography?

Cryptography is the deliberate attempt to obscure or scramble the information so that only an authorized receiver can see the message.

Network security may employ cryptography, but has many other tools to secure a network, including firewalls, auditing, Intrusion Detection Systems, and so forth.

Cryptography would be used only when trying to keep messages secret when sending them across a network or keeping information secret in a file.

## What is the difference between symmetric and asymmetric cryptography?

With symmetric cryptography, the same key is used for both encryption and decryption. The sender and the recipient must already have a shared key that is known to both. Key distribution is a difficult problem and was the impetus for developing asymmetric cryptography.

With asymmetric crypto, two separate keys are used for encryption and decryption. In asymmetric cryptosystem each user has both a public key and a private key. The private key is kept secret at all times, but the public key can be freely distributed.

Data encrypted with the public key can only be decrypted with the corresponding private key. Therefore, to send a message to John it is necessary to encrypt that message with John’s public key. Only John can decrypt the message, as only John has his private key. Any data encrypted with the private key can only be decrypted with the corresponding public key. Similarly, Jane can digitally sign a message with her private key, and anyone with Jane’s public key can decrypt the signed message and verify that Jane actually sent it.

Symmetric is usually very fast and ideal for encrypting large amounts of data (eg, an entire disk partition or database). Asymmetric is very slow and can only encrypt pieces of data that are smaller than the key size (typically 2048 bits or smaller). Thus, asymmetric crypto is commonly used to encrypt symmetric encryption keys which are then used to encrypt very large blocks of data. For digital signatures, asymmetric crypto is typically used to encrypt hashes of messages rather than entire messages.

A cryptosystem provides for the management of cryptographic keys including the generation, exchange, storage, use, revocation and replacement of keys.