# Difference between Encryption and Decryption

In cryptography, encryption is the process of encoding information. Encryption is a process of converting  the original representation of the information into an unreadable form known as ciphertext. Ideally, only authorized parties can decipher a ciphertext back to plaintext and access the original information. Encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor. Whereas Decryption is a method of converting the unreadable/coded data into its original form. Encryption is done by the person who is sending the data to the destination, but the decryption is done at the person who is receiving the data.

we will cover these topics:

## What is Cryptography?

Cryptography is s the practice and study of techniques for secure communication in the presence of third parties called adversaries. Modern cryptography uses mathematics, computer science, electrical engineering, communication science, and physics. For example, when we make payments at Amazon or ebay, we send our credit card information over the internet where someone who gets access to the data cannot understand what data is being passed as the data is encrypted. To decrypt the data, they would not have access. The same applies when someone interferes and hacks the system to receive your email or your whatsapp message – The message is encrypted and cannot be decrypted by the interferer.

## What is meant By Encryption?

Encryption is a process which transforms the original information into an unrecognizable form. To put it simply, encryption is the encoding of information. It is used in a variety of online services to keep your data private and safe: from text messages and emails to banking and transaction information.

In computing, unencrypted data is also known as plaintext, and encrypted data is called ciphertext. The formulas used to encode and decode messages are called encryption algorithms, or ciphers.

To be effective, a cipher includes a variable as part of the algorithm. The variable, which is called a key, is what makes a cipher’s output unique. When an encrypted message is intercepted by an unauthorized entity, the intruder has to guess which cipher the sender used to encrypt the message, as well as what keys were used as variables. The time and difficulty of guessing this information is what makes encryption such a valuable security tool.

## What is meant by Decryption?

Decryption is a process of converting encoded/encrypted data in a form that is readable and understood by a human or a computer. This method is performed by un-encrypting the text manually or by using keys used to encrypt the original data.

## Why use Encryption and Decryption?

The security provided by encryption is directly tied to the type of cipher used to encrypt the data — the strength of the decryption keys required to return ciphertext to plaintext. In the United States, cryptographic algorithms approved by the Federal Information Processing Standards (FIPS) or National Institute of Standards and Technology (NIST) should be used whenever cryptographic services are required.

## Types of Keys

### Symmetric Key:

Symmetric-key encryption are algorithms which use the same cryptographic keys for both encryption of plaintext and decryption of ciphertext.

### Asymmetric Key:

Asymmetric encryption uses 2 pairs of key for encryption. Public key is available to anyone while the secret key is only made available to the receiver of the message. This boots security.

### Public Key:

Public key cryptography is an encryption system which is based on two pairs of keys. Public keys are used to encrypt messages for a receiver.

### Private Key:

Private key may be part of a public/ private asymmetric key pair. It can be used in asymmetric encryption as you can use the same key to encrypt and decrypt data.

### Pre-Shared Key:

In cryptography, a pre-shared key (PSK) is a shared secret which was earlier shared between the two parties using a secure channel before it is used.

## Difference between Encryption and Decryption

Encryption, which encodes and disguises the message’s content, is performed by the message sender. Decryption, which is the process of decoding an obscured message, is carried out by the message receiver.

Parameter Encryption Decryption
What is It is a process of converting normal data into an unreadable form. It helps you to avoid any unauthorized access to data It is a method of converting the unreadable/coded data into its original form.
Process Whenever the data is sent between two separate machines, it is encrypted automatically using a secret key. The receiver of the data automatically allows you to convert the data from the codes into its original form.
Location of Conversion The person who is sending the data to the destination. The receiver receives the data and converts it.
Example An employee is sending essential documents to his/her manager. The manager is receiving the essential documents from his/her employee.
Use of Algorithm The same algorithm with the same key is used for the encryption-decryption process. The only single algorithm is used for encryption and decryption with a pair of keys where each use for encryption and decryption.
Major function Transforming humanly understandable messages into an incomprehensible and obscure form that can not be interpreted. It is a conversion of an obscure message into an understandable form which is easy to understand by a human.

### Encryption algorithms

• AES is a symmetric block cipher chosen by the U.S. government to protect classified information; it is implemented in software and hardware throughout the world to encrypt sensitive data. NIST started development of AES in 1997 when it announced the need for a successor algorithm for the Data Encryption Standard (DES), which was starting to become vulnerable to brute-force attacks.
• DES is an outdated symmetric key method of data encryption. DES works by using the same key to encrypt and decrypt a message, so both the sender and the receiver must know and use the same private key. DES has been superseded by the more secure AES algorithm.
• Diffie-Hellman key exchange, also called exponential key exchange, is a method of digital encryption that uses numbers raised to specific powers to produce decryption keys on the basis of components that are never directly transmitted, making the task of a would-be code breaker mathematically overwhelming.
• Elliptical curve cryptography (ECC) uses algebraic functions to generate security between key pairs. The resulting cryptographic algorithms can be faster and more efficient and can produce comparable levels of security with shorter cryptographic keys. This makes ECC algorithms a good choice for internet of things (IoT) devices and other products with limited computing resources.
• Quantum key distribution (QKD) is a proposed method for encrypted messaging by which encryption keys are generated using a pair of entangled photons that are then transmitted separately to the message. Quantum entanglement enables the sender and receiver to know whether the encryption key has been intercepted or changed before the transmission even arrives. This is because, in the quantum realm, the very act of observing the transmitted information changes it. Once it has been determined that the encryption is secure and has not been intercepted, permission is given to transmit the encrypted message over a public internet channel.
• RSA was first publicly described in 1977 by Ron Rivest, Adi Shamir and Leonard Adleman of the Massachusetts Institute of Technology (MIT), though the 1973 creation of a public key algorithm by British mathematician Clifford Cocks was kept classified by the U.K.’s Government Communications Headquarters (GCHQ) until 1997. Many protocols, like Secure Shell (SSH), OpenPGP, Secure/Multipurpose Internet Mail Extensions (S/MIME) and Secure Sockets Layer (SSL)/TLS, rely on RSA for encryption and digital signature functions.