It's always been difficult to keep secrets. It's even more difficult when necessity forces you to write those secrets down and move them around the Internet, whose open systems make it easy for eavesdroppers to glance at the information we send over the wires.
Encryption is at the heart of most digital commerce done over the Internet.
The email you send on the Net is essentially a digital postcard. A nosy mailman or neighbor can glance at what's written on it as it visits the many stops along the route from the sender to the receiver's mailbox. Not exactly the best way to ensure that sensitive information doesn't get widely distributed to the wrong people. The answer lies in an arcane science known as cryptography . The original message, known as plaintext, is scrambled using a software application called an encryption engine.