Encryption and decryption are both methods used to ensure the secure passing of messages and other sensitive documents and information.
Encryption basically means to convert the message into code or scrambled form, so that anybody who does not have the 'key' to unscramble the code, cannot view it. This is usually done by using a 'cipher'. A cipher is a type of algorithm used in encryption that uses a certain described method to scramble the data. The cipher can only be 'deciphered' with a 'key'. A key is the actual 'described method' that was used to scramble the data, and hence the key can also unscramble the data.
When the data is unscrambled by the use of a key, that is what is known as 'decryption'. It is the opposite of encryption and the 'described method' of scrambling is basically applied in reverse, so as to unscramble it. Hence, the jumbled and unreadable text becomes readable once again.
In network security, password encryption as well as document encryption is a major player. Without it, there would be no 'security' in the network. Also, encryption is used for all sorts of files, and all forms of digital transfers as well. It is used on the internet to safeguard websites and copyrighted material, as well as in bank ATM machines. The encryption process plays a major factor in our technology advanced lives.