Symmetric Encryption
Symmetric encryption is the best-known technique. Use a secret key, which can be a number, word, or string of random letters, is applied on a message to change the content in a particular way. It is very simple as shifting each letter by a number of places in the alphabet. Both sender and recipient know the secret key, Secret key can encrypt and decrypt all messages.
Asymmetric Encryption
When secret keys is exchanging over the Internet might be going the wrong hands. After kept the secret key anyone decrypt the message. Solution is asymmetric encryption, in which there are two related keys--a key pair. A public key is easily available to anyone who want to send a message. A second, private key is kept secret, so that only you know it.
Encrypt message by using the public key can only be decrypt by applying the same algorithm, but by using the matching private key. If message encrypt by using the private key can only be decrypt by using the matching public key.
