I. What is encryption Encryption is a secrecy technique in which the users involved create a real message but this is hidden in some way. One form of encryption is steganography. This is another secrecy technique, a little older than encryption itself. It has been used for thousands of years, but as a primitive form of secret messages. The word itself comes from two Greek words: steganos means “covered” and graphein means “to write.” In ancient times, a man named Pliny the Elder used the milk of the thitymallus plant as invisible ink. In Greece and Persia they shaved a messenger's head, wrote a message on his bald scalp, then waited for hair to grow on it before sending him to deliver the message. Sometimes they went so far as to tattoo the message on his head. Obviously the message couldn't have been extremely urgent. Nowadays the steganography technique is not widely used for security because it has become obscure. It has strengths and weaknesses, one of the main weaknesses is that if the message is found, the secret is revealed. Encryption is another method used to hide the meaning of a message. Cryptography also comes from Greek, specifically from the word kryptos, which means "hidden". Encryption techniques are different from steganographic techniques in that this technique does not hide the actual message, but only the meaning of the message. If the message fell into the wrong hands, the use of encryption would ensure that the message could not be read, while steganography would not, the message would be read. Usually a sender and recipient agree on the type of encryption protocol to use before attempting to send any message. They would also agree h...... middle of paper...... Key and private keys." Public keys and private keys. Np, nd Web. March 18, 2014."History of cryptography." Wikipedia. Wikimedia Foundation, March 15, 2014. Web. March 18, 2014. "Public Key Cryptography for Dummies." . Np, nd Web. March 17, 2014. "A Brief History of Cryptography." the code in our encryption challenge, March 17, 2014. Encryption.” NSRP: Cryptography. Np, nd Web. March 18, 2014."Cryptography Defined/A Brief History." Cryptography Defined/A Brief History. Np, nd Web. March 18, 2014."Private key (secret key)." What is it? Np, nd Web. March 18, 2014. “Public and Private Key Cryptography Systems".. 2014.