Data stored by computer systems is exposed to several risks. People may steal or distort the data for selfish motives or just for fun. VIRUS (Vital Information Under Siege) and hacking are well-known threats. Antivirus programs should be installed and updated from time-to-time. Cryptography can be used to prevent interception of data in the course of transmission. In this technique, information is transformed into an unreadable format called ‘hypertext’. Only those having a secret key can decipher the format.