To send a message over the network securely we must ensure that if it is intercepted, that the information sent cannot be read. The encryption it is a way to make the message we send unreadable to everyone except the receiver. This is why in the security sector we are interested in having good encryption methods. These methods are the techniques studied by the field of cryptography: encryption and decryption. Good encryption of the message to be sent, and that we are then able to decipher it, It is what assures us the security in the communication in the network.
according to the key:
A key is the "code" we use to encrypt and decrypt the message. Namely, to switch from the normal message to the encrypted message, we use a key. And vice versa to decrypt.
- The asymmetric cryptography, the of "public key”, is a system that uses pairs of braces. In each pair there is a public key and a private key that only the user knows.. Both keys are used to decrypt the message., making use of one-way mathematical functions. The user who sends a message encrypts it using the public key, but the trick is that the message cannot be decrypted without the receiver's private key. Messages via email use this encryption.
- Symmetric cryptography: both receiver and sender must know the key, and everything is encrypted and decrypted with this key. This system was used in the Enigma machine, for instance.
Depending on the situation and the system we are installing, we are interested in one method or another, or a mix of the two. Also, the asymmetric cryptography system introduces us to the concept of digital signature. Since the private key only has the issuer, no one can impersonate him.
According to algorithms:
An algorithm is the “rules” of the encryption process. Namely, the instructions of the process that encrypts. Some examples of encryption algorithms are Triple DES, RSA y AES.
- Stream encryption: The text is divided into small blocks that are encrypted using a key that depends on many previous blocks.. The key is then different for each cipher, and it depends on the message itself and the previous ones. With this type of encryption, applications that operate in real time can be protected., such as telephone conversations and audio and video applications.
- block encryption: In this method, the message is divided into longer blocks of a fixed size.. We encrypt them separately using the same key for each block, and this determines the order in which the blocks are treated (Transportation order, encryption, etc.). It is the preferred system in software applications. The DES and Triple DES encryption systems use this block encryption method.