The evolution and modern methods of cryptographic systems

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.

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.

An attack has been found on some implementations of RSA digital signatures using the padding scheme of PCKS-1 when the public key e = 3. A similar attack could also be applied to implementations of digital signatures as specified in American National Standard (ANS) X9.31. Note that this attack is not on the RSA algorithm itself, but on improper implementations of the signature verification process."

Although the report indicates that the attack can be caused by improper implementation, the conclusion in the end is that there is still a possibility that information is not totally secured.

Another online source indicates the following cryptography vulnerability that is important to consider, particularly when using WEP (Wired Equivalent Privacy) cryptography.

WEP cryptography is not very secure at all. A paper from cryptography analysts called the encryption algorithm "kindergarten cryptography." Actually, software exists that exploits a huge security hole in the encryption standard. This software listens to the encrypted network traffic, analyzes it, and after only a few hours it reveals the password to enter the network in clear text. The more traffic on the network, the easier it is to find out the password because some packets are particularly weak because they carry a bad so-called initialisation vector (IV). Recent access points try to avoid these bad IVs, so it is getting harder to exploit the hole."

Other important considerations when implementing cryptography are the following.

Securing physical access to an area

Confidentiality of encryption methods used

Making backup

Continuous research and study that can ensure the strength of cryptography method being used.