Cryptography concepts and applications

Cryptography

History of Cryptography

The history of cryptography dates as far back in the Egyptian times. Cryptography is a means of concealing or hiding true information in forms that are incomprehensible to others. An Egyptian scribe made use of this by converting hieroglyphic standards in other form of scribbles to secretly communicate.

The main purpose of cryptography is to maintain confidentiality of information. Within its history, the cryptographic styles have developed from simple forms of conversion into complex methods that we have today. Simple conversion includes rearranging of letters (i.e. ephl = help), or replacing or shifting letters (i.e. fly = gmz). Some notable personalities who made use of these forms of cryptography includes Julius Ceasar who used a shift of 3 letters to communicate with his generals (Wikipedia Online), and Thomas Jefferson who developed a wheel cipher that was used by the U.S. Navy during the World War II (Herbert, 2001). Complex methods, on the other hand, are those that were the result of our modern technology such as data encryption, digital signatures, authentication of senders/receivers, public key cryptography, and secure computation among many others.

The World War I and II similarly have made use of cryptography in the battle field. The German's Enigma and the Japanese Purple machine are two of the famous machines used in the war (Herbert, 2001).

The introduction to the present day Data Encryption Standard (DES) was the "Feistal Ciphers," developed by Dr. Hoist Feistal in the late 1970s (Herbert, 2001). The Feistal

Ciphers was developed into DES by the National Security Agency which was thereafter improved by Xuejia Lai and James Massey into a stronger 128-bit cipher called IDEA or International Data Encryption Algorithm. One after another, many developments have transformed cryptography into complex forms being used in today's modern technology.

The Modern Cryptography

Today's cryptography features different methods that cater to particular need in concealing information. Following are two of the modern methods of cryptography.

Symmetric-Key Cryptography

This method of cryptography allows both the sender and the receiver have similar or common keys for encryption and decryption. Compared to other form of cryptography, symmetric-key is simpler and faster (Webopedia). However, this method requires secured process of exchanging keys by communicating parties. DES is a good example of symmetric-key cryptography.

Public-Key Cryptography

Unlike symmetric-key cryptography, communicating parties do not share keys. Instead, a pair of keys, public and private, is generated wherein the public key can be distributed freely but the private key must remain concealed. Basically, the purpose of the public key is to encrypt while the private key is to decrypt (Wikipedia). Webopedia has the following simple example of the use of public and private key.

When John wants to send a secure message to Jane, he uses Jane's public key to encrypt the message. Jane then uses her private key to decrypt it."

Elliptic Curve Cryptography

This type of cryptography is designed to cater greater security in the future and as an enhancement to the RSA and Diffie-Hellman public-key systems which make use of 1024-bit parameters. However, this parameter size is only presumed to be sufficient until 2010. The elliptic curve cryptography aims on increasing the parameter size that can cater to another decade of use.

Where Cyptography is Applied

Almost all of today's form of information technology that requires information security to maintain confidentiality makes use of cryptography as a security component. The different techniques of information security such as data authentication and digital signatures will not be efficient without the employment of cryptography where encryption and decryption of data are the main course of actions.

Cryptography is applied in many of the public and private systems where information travels across the World Wide Web. This includes systems of the different agencies of the government such as NASA and FBI, or commercial systems such as the e-commerce systems of various companies and organizations, or even systems of common and private individuals using the Internet.

Among the most common technology that makes use of cryptography are the credit card companies. Using credit cards online requires sufficient data security to ensure that the information necessary to enable a credit card owner (i.e. credit card number, personal information) make purchase or payment transactions online are authenticated and similarly secured from any information theft. In such need, cryptography plays an important role by encrypting real data into another form before they are transmitted to the World Wide Web. In this manner, if the transmitted information is intercepted by a cyber-thief, the information will remain useless to him since it is in an encrypted form that is incomprehensible to him.

Banks is another common user of cryptography and whose input and output information are critical and must remain confidential. These days, a large percentage of banking transactions can be done online. Hence it is very critical that the information of bank customers is highly secured. If one is to access a banking online site, it is noticeable that a warning is provided to the user informing him that the site he is about to access is secured. Moreover, such secured sites are marked by a lock icon shown at the bottom part of the user's browser. Within a user's session in a secured site, it is typical that cryptography works at the background of every information exchange that occurs between the user and the site's system. This happens to ensure that all information sent and received by the user is authenticated and secured.

There are more areas particularly in the World Wide Web where cryptography is being used. All of which aims to ensure that data transmitted between the sender and receiver remain secured and authentic.

Security Considerations

Within the history of cryptography, the methods at which data is encrypted have transformed from the simplest form into complex ones. Such development occurs in an aim to ensure that stronger security is enforced on information exchange. It cannot be considered though that cryptography, via encryption and decryption of data, is a 100% guaranteed data security measure. This is because several reports show that cryptography still has a small amount of vulnerability. it, however, reduces at a high percentage the possibility that information can be attacked by malicious activities. One proof to the vulnerability of cryptographic encryption method and something to consider when implementing cryptography was recently reported by the Computer Security Resource Center. The report states the following.