What is cryptography?

Cryptography is the science of transforming information you can read (in plaintext) into information someone cannot read. In this process, information is coded (encryption) to stop information from being read or altered by anyone but the intended recipient. It may be intercepted, but it will not be intelligible to someone without the ability to decode (decryption) the message. Encryption and decryption require a mathematical formula or "algorithm" to convert data between readable and encoded formats and a key. A key is a unique number which is combined with the plaintext to produce the encrypted message or the Digital Signature.