What is Cryptography?

Technology has developed throughout the years, which has been shown by changes in different aspects of how people live their daily lives. One example could be the means of transportation which started from horses during early times to carriages, invention of automobiles, aircrafts, submarines and many more which we use at present. Through centuries, sending of messages has also evolved from messenger mail to electronic mail via the World Wide Web. Along with these are rising security threats to senders and receivers of those messages who fear that their mail would be opened by someone else.
It is and has been the same problem ever since. How can these security threats and privacy invasions be avoided then? The main topic of this research is the importance of a science that helps everyone. It could be in terms of technology to the benefit of computer enthusiasts and industrialists, or simply for protection of the privacy of each citizen. The following pages would give the readers a brief introduction of the subject at hand, Cryptography. Along with its definition, history, forms and uses, readers would also be able to learn how important this science is and why each person should use it in their daily communication.
According to the Merriam-Webster online dictionary, Cryptography is the enciphering and deciphering of messages in secret code or cipher, the computerized encoding and decoding of information. It is also known as secret writing. Derived from the Greek words kryptos, which means hidden and the grafo, meaning write, is the transformation of data into a secure message, so that unintended recepients would not be able to understand or use them. (Wikibooks, Inc. , 2007).

Cryptography is used to hide information by means of encryption, therefore making data unreadable to those who don’t have the secret key that can decipher or decrypt the message into an understandable one. Encryption is done when information is transformed into something which others might see as useless. This is called ciphertext. The act of transforming the said information into an understandable format with the use of a cipher or secret key is called decryption. (Wikibooks, 2007) The use of cryptography is seen today through its many uses.
These include the security of ATM cards, electronic commerce and computer passwords. These are used for access control and confidentiality of secure information. (Cryptography, 2007) Such techniques like microdots and combining words with images are used by cryptographers to hide information from unintended recepients. (Pawliw, 2006) The earliest known use of cryptography is Classical Cryptography. It shows that it has been thousands of years since cryptography was first done. History has stated that the first proof of the use of cryptography dates back to 2000 BC.
It has been related with the Egyptians’ practice of hieroglyphics which consisted of complicated pictograms seen carved into monuments of Ancient Egypt. These pictograms were hard to interpret and only a chosen few knew what their real meanings were. Some time within 500 and 600 BC, Hebrew scholars made use of simple substitution ciphers like the Atbash Cipher in order to solve these encrypted messages. According to Wikibooks, the first known use of a modern cipher was by Julius Caesar (100 BC to 44 BC):
“…who did not trust his messengers when communicating with his governors and officers. For this reason, he created a system in which each character in his messages was replaced by a character three positions ahead of it in the Roman alphabet. ” (Wikibooks, 2007) By the time of World War II, there has become a great use of mechanical and electromechanical cryptographic cipher machines, but the usage of these was very impractical. During this time, there were various developments in both mathematical and practical cryptography.
When the period of modern cryptography began, Claude Shannon, father of mathematical cryptography, published the paper Communication Theory of Secrecy Systems in the Bell System Technical Journal in 1949. Shortly after that, along with Warren Weaver, he published the book Mathematical Theory of Communication as well. Because of those publications, a solid theoretical basis for cryptography and for cryptanalysis was established, which made cryptography known only by secret government communications organizations such as the NSA.
It was only in 1969 that the public again saw developments in the field of cryptography: “First was the DES (Data Encryption Standard) submitted by IBM… in an effort to develop secure electronic communication facilities for businesses such as banks and other large financial organizations… it was adopted and published as a FIPS Publication (Federal Information Processing Standard) in 1977…has been made effectively obsolete by the adoption in 2001 of the Advanced Encryption Standard…DES was the first publicly accessible cypher algorithm to be ‘blessed’ by a national crypto agency such as NSA.
The release of its design details by NBS stimulated an explosion of public and academic interest in cryptography. ” (Wikibooks, 2006) Here are the important terms related to Cryptography in detail; Encryption is the act of hiding information using cryptography. Processed information in this manner is said to be encrypted. Decryption is the process of translating encrypted information. The Key is like a password used to encrypt and decrypt information. A transmission channel used to transmit information in secrecy is called a Secure Line, while a Public Line is the opposite.
An example of which are public pay phones and the Internet. (Wooledge , 2000) There are several types of Cryptography being used today. In order to further explain the types of Cryptography, Wooledge compared the Key to a key to a door. First among these is the Symmetric Cipher, which can sometimes be called a symmetric key. Most of the time, it is used for simple types of cryptography because a same key is used to encrypt and decrypt the secret message.
“Everybody who should have access to the room is given a copy of the key…put new information in, take old information out…if you send somebody a copy of the key by way of the Post Office, somebody working at the Post Office could intercept this key…allow them to access this same locked room, and do the same things with it…letting them read everything you locked up with that key, even letting them modify it. “(Wooledge , 2000) The Public Key Cryptography is more complex because in this type of cryptography there are two keys used and together, they are called a key pair.
The key used to encrypt is called the public key, which can be given to anyone in order to send information to the owner of the private key, which will be used to decrypt information sent to him. The most common example of this is the use of electronic mail over the internet, also known as email. The public key is an email address which one gives out to his friends. This allows them to send information to the holder of the secret key, the owner of the email address, the only one who has the password to open and translate the information sent to him or her.
(Wooledge , 2000) A One Time Pad is used to send high security messages such as national secrets and is considered the only perfect encryption in the world. In this type of encryption, both the sender and receiver has a copy of the pad to be used as a symmetric key to hide and unhide a message sent over a secure line and destroys them after it has been used. A good example of this is the one seen in Mission Impossible movies, wherein Ethan Hunt receives messages that self-destruct. (Wooledge , 2000)
For the sake of totality, it would be best to include Steganography, the science of hiding information from people who would spy on a person. This type of encryption is designed not to let spies know that there is indeed a something hidden in a certain message. It is very effective, but only used occasionally. (Wooledge , 2000) Along with the internet, there is a large growth in the variety of forms of electronic communications, making its security very important. There are a number of enumerated uses for Cryptography such as protection of e-mail messages, credit card information, corporate and other important information.
(Jupiter Media Corporation, 2004) After a brief background on Cryptography, readers would come to know why it is important to use them in their daily activities. The following are common concerns, goals or objectives that answer the above stated question. Message Confidentiality; Encrypted messages would only be understood by intended recepients of a certain message. If a sender would want to hide certain information from the public or from someone in particular, it would be best that cryptography is used.
In that manner, only the receiver would have the key to translate the message into a useful and understandable one. Message Integrity; If an encrypted message is intercepted and changed during the sending process, it would easily be known by the receiver, which secures its integrity. Sender Authentication; It would be possible to make sure of the identities of both sender and recepient of the message. With cryptography, the recipient would be able to verify the true identity of the sender, along with the origin and destination of the message.
Sender Non-Repudiation; This would prevent a sender from denying an intention to send and that he or she is the true sender of the said message. (Wikibooks, 2007) Though these cryptographic procedures are effective enough to achieve the goals, and concerns mentioned, it is still important for receivers and specially senders to practice caution such as creating a password with a very strong integrity, logging off private systems when they are not being used by the owner and keeping all private information to oneself. (Pawliw, 2006) Works Cited Cryptography. (2006).
In Merriam-Webster Online Dictionary [Web]. Merriam-Webster, Incorporated. Retrieved January 24, 2007, from http://www. m-w. com/cgi-bin/dictionary? book=Dictionary&va=cryptography Cryptography. (2007). In Wikipedia, the Free Encyclopedia [Web]. Wikimedia Foundation, Inc.. Retrieved January 24, 2007, from http://en. wikipedia. org/wiki/Cryptography Pawliw, B (2006, January 13). Cryptography. Retrieved January 24, 2007, from Search Security. com Web site: http://searchsecurity. techtarget. com/sDefinition/0,,sid14_gci214431,00. html Wikibooks, (2006, November 1).
Cryptography/History of Cryptography. Retrieved January 24, 2007, from Wikibooks, the Open-Content Textbooks collection Web site: http://en. wikibooks. org/wiki/Cryptography/History_of_Cryptography Wikibooks, (2007, January 10). Cryptography/Introduction. Retrieved January 24, 2007, from Wikibooks, the Open-Content Textbooks Collection Web site: http://en. wikibooks. org/wiki/Cryptography/Introduction Wooledge , G (2000, October 11). What types of cryptography are there?. Retrieved January 24, 2007, from wooledge. org Web site: http://wooledge. org/~greg/crypto/node5. html