Encryption and Decryption

Encryption          :

is a process of converting a plain text or data into cipher text so everyone can not read the data except the sender and the receiver itself. Encryption is the best tool to protect data, privacy, and your secret.

Decryption         :  

is a process of converting a cipher text become data which is needed by the recipient to understand what the sender wants from the encrypted data.

Advantages of encryption :

Guarantee the confidentiality of any information,
Tackling the phone tapping,
Prevent unwanted access to documents and e-mail messages,
High encryption level is difficult to break.

Disdvantages of encryption :

Messages can not be read when the message receiver forget or lost keys

Encryption of terorist planning  

Advantages of Decryption :

Easy to understanding the content of the message

Disadvantages of Decryption :

Because the encryption program can use the same algorithm in different ways, thats why the recipient of the encrypted information must have the same program with the sender to decrypt the data they receive.

Methods of Encryption 

      1. Symetric key encryption

Is a method where the sender and the receiver make a secure internet session by create a single encryption key, so the sender and receiver use the same key.

Symetric encryption is easy and fast to use, but it is not safe because someone could intercept the key and decode the message. But because of its speed, it's commonly used in e-commerce transactions. The strength of the encryption key is measured by its bit length. Today, a typical key will be 128 bits long (a string of 128 binary digits).

2. Public key encryption (asymetric) 

is a method which is more safety than symetric key encryption because it used two keys : one shared (or public key) and one totally private key. 

The public key is made available to anyone who wants to send encrypted information. They just can encoding, not decoding the data. 

The private key stays safe with you. When people want to send encrypted information, they using your public key. When you receive the cipher text, you decrypt it with your private key. Asymetric encryption added level of security to your data, but there is more computing time required, so the process is longer than the symetric key encryption. 

      

How the Symetric key encription and the Public key encryption works?

Symmetric and public key encryption uses two different algorithms to produce ciphertext.

In symmetric encryption, the algorithm breaks down the data into small pieces called blocks. Then it would replace the letters position, change the information in each block into numbers, compresses and expands the data, and then run it through a mathematical formula including the key in it. Then the algorithm will repeats the process.

In Public key encryption (asymetric), the algorithm treats the text as a large number, then multiply it to a larger number, and calculates the remainder after dividing by other third-largest number. Finally, the rest of the number is converted to text back. This algorithm is used in a large and dynamic communication network.