2.3 Encryption

## Encryption
- Scrambles data for secure transmission.
- ... making data meaningless/unintelligible so it doesn’t make sense to hackers and other attackers.
- Uses an algorithm / key
- plain text is changed to cipher text
### How encryption improves data security
- Encrypted text is meaningless
- Need the key to decrypt the text
## purpose of encrypting data
- To help keep the data secure
- To make the data meaningless
	- If the data is intercepted, it cannot be understood
### how to make the encryption more secure
- Increase the length of the key
- Uses a more complex encryption algorithm
## how to increase the level of security provided by the encryption
- Increase length / more bits used for key
- It will have less chance of decryption by brute force method
### **Plaintext and Ciphertext**
- Plaintext is the original data that is being sent
- Ciphertext is the text produced after encryption
### **Symmetric and Asymmetric Encryption**

### Symmetric Encryption:
- It uses an encryption key for the encryption process; the same key is used for encrypting and decrypting the data.
#### How data is encrypted using symmetric encryption
- Plain text is encrypted into cipher text // cipher text is decrypted into plain text
- Data is encrypted using an algorithm that uses a key
- The key can be generated using an algorithm
- The key is transmitted to the receiver
### how the data is encrypted
- Encryption key is used
- Encryption algorithm is used
- Encryption key / algorithm is applied to plain text to convert it into cypher text
- Same key is used to encrypt and decrypt the text
### Asymmetric Encryption:
- Uses a public key and a private key. The public key is available to everyone, whereas the private key is only available to the user.
- The receiver would have the private key, and they would send the public key to the sender. The sender can encrypt the message with the public key, and the data can be decrypted using the private key.

Data is encrypted using an encryption key. This is a type of **algorithm** that scrambles the **plain** **text** and turns it into **cipher** **text**. This makes the data **meaningless**.
A **public/private** key is used to encrypt the data. This key cannot be used to decrypt the data. A **private/public** key is used to decrypt the data. Any device is able to request the **public** key, but only your device knows the **private** key.
### similarity between symmetric encryption and asymmetric encryption:
- They both use a key
- They both scramble(打乱) the data
- They both turn plain text into cypher text
### differences between symmetric encryption and asymmetric encryption:
- Symmetric uses one key whereas asymmetric uses two keys
- Symmetric sends the key with the data whereas asymmetric does not
- Symmetric decrypts the data using the same key whereas asymmetric decrypts the data using a different key
### why a person would use asymmetric encryption instead of symmetric encryption.
- The process is more secure.
- Do not need to worry about key exchange.