Tools : Encryption

 Encryption definition

Encryption is the foundation of many aspects of security. For Example encryption protects messages sent across the Internet and protects files stored on serves.

In cryptography, encryption is the process of encoding messages such a way that eavesdroppers or hackers cannot read it, but that authorized parties can.

In an encryption scheme, the message or information is encrypted using an encryption algorithm, turning it into an unreadable cipher text. This is usually done with the use of an encryption key, which specifies how the message is to be encoded. Any adversary that can see the cipher text should not be able to determine anything about the original message.

 An authorized party, however, is able to decode the cipher text using a decryption algorithm, that usually requires a secret decryption key, that adversaries do not have access to. 

• Passwords, messages, files, and other data is transmitted in scrambled form and unscrambled for authorized users.
• Involves using special mathematical algorithms to transform digital data in scrambled code.
• Most widely used method uses a private keys unique to each individual

There are two basic types of encryption schemes:

1.      Single Key

Figure 1 : Single Key encryption. 

Both the person who encrypts the message and the person who

decrypts it use the same key. The system are fast, but it is 

difficult to safely distribute the key.

Figure 1

2.      Public Key Encryption

Uses two different keys, one private and one public. The keys are mathematically related so that data encrypted with one key can be decrypted using only the other key

Public key encryption

Figure 2 : Dual-key encryption . Alice sends a message that only 

Bob can read. With a dual-key system, one key encrypts the 

message, the other decrypts it. Once Bob's public key is applied to 

the message, only Alice's private key will retrieve the message.

 Keys are usually very large prime numbers.

Figure 2

Figure 3 : Dual-key encryption foe message authentication. 

Bob sends a message to Alice at the bank. Using his private key 

ensures that the message must have come from him. 

Using Alice's public key prevents anyone 

else from reading the message.

Figure 3