CORE VOILÀ

Hashing is process of converting any size of data into fix size of data by performing mathematical operations. A message to be hashed is called input; the Algorithm is used to do so is called hash function; the output is called hash value. There are many algorithm which used to generate hash value like MD5, SHA-1, SHA-256, Tiger etc.  Hash function generates a unique value, this means two input always generates different hash value.    Hash value can not be decrypt once it's hashed, this is the difference between encryption and hash. Encrypted value can be decrypt using keys but we can not extract input from Hash value. Common use of Hash is to store password into database. 

Cryptograph means secret writing, in order to make information secret we use cipher, an algorithm that converts plain text to cipher-text. Cipher has been used long before computer existance. In 44 BC  Julius Caesar uses the technique now called Caeser Cipher  to send message. He used to shfit the letter by 3 character.  Another great example from history, Nazis Enigma Machine used during war to translate message. Data Encryption Standard (DES) is the first algorithm written for Cryptography in early 19th century. A process of making text secret is called Encryption and the reverse process is called Decryption. So far the Cryptography technique we mentioned  above relies on keys known by sender and receiver. Though manual sharing key is not good idea, solutions is to automate exchange of keys. We can do this by using one way functions , to understand one way function here is the Good example of one way function is Diffie-Hellman key exchange .  There are two types