The term cryptography works to protect the data securely, We normally protect the data to avoid access from unauthorized users. Many people use the cryptography technique to protect the data of corporate secrets and personal data.

It protects to avoid access from the malicious and the unauthorized user. The concept of protecting the data from authorized users is called cybersecurity. Let us discuss some of the methods and techniques in cryptography. So what actually the cryptography mean? we will also discuss some of the various classifications and algorithms that are present in the cryptographic technique.

Let us take an example for a better understanding of the cryptographic techniques, suppose let say there are two users. User A and User B, User A wants to send the information to the user B who is located at different locations, The User A doesn’t want to send the Information such that no third-party users are able to read the data.

The data or information will be sent privately. It says no other member is able to access the information except the authorized user. User A uses the public network called the internet to transmit the data from User A to User B. The main goal of the Cryptographic Technique is to provide secured data transmission between the sender and the receiver, and we also should be maintained secured from the third party users.

Let say, suppose there is a person who wants to read the private information that is sent between User A and User B, the third person got access to the information that is sent by User A since he has the access to the information sent by the User A, the third party can do many works other than eavesdropping.

As we take an example earlier when the data is transmitting between User A and User B., there is one more access to the person called the third party user. The third-party User has the ability to change the Message’s internal information and replace it with any other information in it.

This is the basic scenario where the data is eavesdropped on by the third party user. This leads to a difficult problem that one person’s private information is get leaked to an unknown third-party user who has bad intentions.

So in order to make sure that no one can access the information while transmitting the message, we check for secure communication. To check secure communication, we use the cryptographic Technique. The basic definition of Cryptography is, it is a set of algorithms and Techniques for providing secure communication during the transmission of data. Let us know the concept of how secure communication is maintained. suppose we send the information to transmit the data to the other side of the user.

While transmission we convert this data into the numeric form and the numeric form is then converted into encrypted data using a key called the encryption key. We use this encryption Key in the encryption algorithm, after we apply the encryption key and converted the numeric message into the form, we get data called the ciphertext.

The Ciphertext is where we cannot understand the data by seeing it. After converting into the form of the ciphertext we send this data into the network, where the other person can receive the message uses a key called the decryption key.

The decryption key is used to decrypt the data that is converted into the numeric form and it can use the ciphertext as the parameter and the user can receive the message what is actually sent by the sender. If any error occurs during the transmission of the data, we use some of the cryptographic Techniques.

Let us briefly understand some of the cryptographic techniques. The cryptography will convert the message into an unreadable form, that converts the number into any random form and uses a key called the encrypted key to encrypt the data. after we apply the encryption key for the numeric form, the user gets a new type of value in the cryptographic technique, the new type of the key is called the Ciphertext.

If user A sends this Cipher text over the network communication, there is no need to check if any malicious user got access to the information. Even the third-party users discover the message while transmission of the data, the third party user cannot decrypt the data without knowing the key for the decrypted data. Even the receiver needs to know the decrypted key to decrypt the data into the original plain text.

Now we convert this ciphertext to its respective plain text after the decryption key is used. The errors may occur in the middle of the transmission, the error represents that the third party user has sent the information or changed the internal information in the data.

Now, the modern cryptography security techniques mainly depend on the encryption and the decryption key on both sides of the network. By referring to the keys and the algorithm, we classify some of the methods and the Techniques. Cryptography is also mainly divided into different categories.

They are symmetric-key cryptography and asymmetric key cryptography. It is also known as public-key cryptography. Symmetric key cryptography can again be classified into many different types like classical cryptography and modern cryptography.

The classified cryptography can also further divided into two categories. One is called transposition cryptography and the substitution cryptography. Coming to modern cryptography, modern cryptography can also be divided into different types called the stream cipher and the other is the block cipher.

Let us know in detail about each type of cryptography technique in detail. Firstly we have the symmetric Technique, in symmetric cryptography, we use symmetric algorithms, these symmetric algorithms can use the same keys for the encryption of the data and for the decryption of the data.

These encryption and decryption keys can be identical. But due to the same keys at both encryption and decryption. It may be a simple transformation to find out the keys, we use the shared secret key where two or more parties are used for maintaining the private information in it. For this, both parties need to have the access to the information to access the secret key.

In cryptography, the one-time pad encryption is a type of encryption technique that cannot be cracked but requires the use of a single-use pre-shared key that is not smaller than the message being sent. In this technique, the plaintext is paired with a random secret key.

The main disadvantage in the symmetric encryption algorithm is when we compare it with the asymmetric key is that it uses more keys in it. The symmetric algorithms use the different types of standards called the DES algorithm. Let us discuss the transposition cipher, the transposition cipher is a type of method that we use by the positions that held in plain text. It can be a character or it can be the set of the characters in it.

We shift these plain text into the regular system. Another type of symmetric method is the substitution cipher, the substitution cipher is used to encrypting the units of plain texts. These are replaced with the ciphertext. We write these alphabets by writing on the keyboard by removing all the letters that are present in the alphabet.

Now let us know the brief introduction to the types of asymmetric cryptography. Asymmetric cryptography has two types. They are called the Stream cipher and another one is called the block cipher. Normally, we can encrypt the information or the data only a bit at a time.

But using the stream cipher, we can encrypt the data in to of bytes or it can be encrypted by a single bit. Whereas in the block cipher, in the block cipher, it acts as an encryption algorithm, we apply these algorithms to encrypt the data in a block. Instead of encrypting only one bit at a time as we do it in the stream cipher, we can encrypt the data by a set of bytes.

We use the AES algorithm for the block cipher that encrypts the data. The AES algorithm can be in 128 bits that consist of a predetermined length in it. It can be of a 128 bit, 192 bit or it can be 256 bit. The block cipher can be operated on a fixed number of bits. We have public-key cryptography, private key cryptography.

The public key cryptography that we use can be used widely, the private key can be accessed and owned by only the authorized user. We use two types of functions in it. The private key is accomplished by the two types of function. the one is authentication. The authentication shows whether the data is accessed by the authorized user or not.

In the authentication, the public key is verified by the holder of the key, the private key is sent to the information and only the private key holder can access the data and for the decryption, we decrypt the data that we have encrypted with the public key in a public key encryption system. Any person can encrypt the message by using the public key on the receiver side. The public key can be accessed by any of the users.

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