The process of cryptography can be described as one of the methods employed to protect your digital or electronic information. It’s the method of protecting digital objects by changing or converting them to an unreadable format in a readable format.

It is the study of formulating rules or protocols that aid in preventing information from being read by the anyone else or by authorization.

The term “cryptography” is derived of two Greek words: one is crypto, and the other one is graphy, which means to be secret in writing. As we have discussed, it is used to protect electronic data, so it could be used to shield your video messages, videos images, or other files from being accessible to the public.

**Objectives Of Cryptography**

The following are the four goals of cryptography :

The following are the four goals of cryptography :

- Confidentiality
- Authentication
- Integrity
- Non – Repudiation

**(1) Confidentiality**Confidentiality is the simple meaning that you make your data confidential so that nobody other than the authenticated user is able to access your data. It is the certain that your information is confidential and only between you and the recipient.

**(2)”Authentication”**– Authentication provides an assurance regarding the authenticity of the sender and receiver who are involved in the exchange.

**(3)-Integrity**– Integrity means that you can be sure that the information transferred from the part of the sender is exactly the same as that which the receiver received. It means that information sent between the sender and receiver are not altered or modified.

**(4)(non-repudiation)**It is clearly understood by the example of SMS. When we send someone an SMS, there is no way to erase the message from the receiver’s side. Therefore, after sending it is impossible for the sender to deny it , and this is an important aspect of Non-Repudiation.

The terms most commonly used in Cryptography and their significance

**Encryption**The process in cryptography through which readable data transforms into unreadable format is known as encryption.

**Decryption** The process is the reverse method of encryption where an non-readable format data transforms into accessible data.

**Plain Text**In terms of Cryptography Plain text is the meaning of text that is in an readable format and is created through the sending.

**Ciphertext**It is text that is created by the process of encryption to shield it from public, and once it is accessed by the sender, it is changed to plain text.

**key:** The key is the primary element used in Encryption and decryption. It is also called the secret of Cryptography.

**Types Of Cryptography **

There are two kinds of it:

Symmetric Key Cryptography

Key cryptography assymetric

**Symmetric Key Cryptography**

In this kind of cryptography, the exact same keys are used both by the sender and receiver to transmit information. The most common type of cryptography used is Symmetric Key Cryptography. easiest one where only a one key can be used both by the sender and receiver.

It is also recognized as secret key cryptography due to one key employed.

**Examples**Examples of HTML0 DES, Blowfish, AES, IDEA etc are the most prominent examples of making use of Symmetric Key Cryptography.

**Advantages**:

Its efficiency is higher than other forms of cryptography.

It is mostly utilized to send long messages**Disadvantages**:

Key Exchange makes it not good

There are many keys that are required due to the length of messages, so their distribution could be challenging.

**Key cryptography with assymetrical symmetry**

It is also known as public key cryptography , and there are two keys that are used. One key is known as a private key, while the another key is known”public key. Because of this, it is also referred to as cryptography with public keys.

The public keys are used for encryption of messages, and private keys are used to facilitate the decryption of messages.

First, the sender transmits an encrypted message, after which encryption occurs when keys 1(public keys) is utilized. The message is then converted to encrypted text, and then it travels through the network, arriving the receiver just before. Receiver holds key2 or private key, which is the key by which message is encrypted back into its original format.

The reason for using encryption with public keys is security and protection of information. It also serves as a digital signatures, which are used to authenticate the sender.

**Advantages**:

There is no reason to share the same key with both the receiver and the sender the same channel of communication, which eliminates the need for sharing keys.

Key management is superior in assymetric versus more symmetric.

**Disadvantages**:

The time required is long in converting cipher text into simple text

Everything that are included in the book are extremely complex in comparison to the symmetrical.

**RSA Algorithm in Cryptography:**

Select two prime numbers such as 3,7, 2.. etc. and label these as Q or P. In the majority of cases, the values for P and Q are mentioned when you ask the questions.

Now , we must find an n value that is the equivalent of the product of P and Q.

Once we have gotten the values of the n number, we need to analyze phi(n) to determine if it is what is the sum of (p-1) and (q-1)

After determining what is the value for both n as well as phi(n) We will determine what e is worth,. This is able to be determined using two criteria:

- 1<e<phi(n)
- GCD (phi(n),e) is 1. (HCF from phi(n) and e should be 1.)

Calculate now the value of encryption

C=Me mod n (value of M is mentioned in the context of the question)

Then , calculate the value of decryption

M= C^d mod n

If the M value we received in 6 is the identical to that given in the answer, we’ve got identical output when decryption and encryption are completed.

**Digital Signature**

Digital signatures are file that is attached to information or data file to authenticate the contents and the sender.

Algorithm in Digital Signature

Three algorithms are utilized by digital signatures in Cryptography:

**Key Generation**–

This algorithm creates the private key out of several private keys after deciding on one, it decides on the key it’s associated with.

**Signing Algorithm**:

In the process of signing this algorithm is employed to obtain signatures using a the file as well as private keys.

**Signature Verifying Algorithm**:

It is a requirement allows a message to accept or deny a claim to be authentic.