The history of cryptography begins thousands of years ago. Cryptography is one of the oldest fields of technical study we can find records of, going back at least 4,000 years, was used in the field of defense and military. The first use of the encryption process for the transmission between sectors of the army are of the Pharaohs. It was also mentioned that the Arabs have attempted in the field of ancient encryption. And Chinese used many ways in the science of cryptography and encryption for the transfer of messages during the war. It was their intent from the use of encryption is to hide the true form of the messages even if they fell into the hands of the enemy, it was difficult to understand. The best way used in the old was Julius Caesar one of the Roman emperors. In the present age has become an urgent need to use this knowledge "encryption" and it was connected to the world interconnected via open networks. Since these networks are used to transfer information electronically, both among ordinary people, or between public and private organizations, whether military or civilian. Must be ways to preserve the confidentiality of information. Has made great efforts from all over the world to find the best ways in which they can exchange data with the possibility of non-disclosure of such data.(Washington & Trappe, 2002)
What's the meaning of Cryptography? The word comes from very old Creek, and is the union of two words: krypto="hidden" & grafo="to write" . so the literal meaning is "hidden writing": is the process of how to make that you write obscure , unintelligible to everyone except whom you want to communicate with. (History of Cryptography, 2010)
How Cryptography works? Cryptography algorithm is a mathematical function used in the process of encryption and decryption. It works in combination with the key or password, number or phrase to encrypt the text readable and security of the encrypted data depends on two important strength of the encryption algorithm and secret key.
How many type Cryptography? There are two type of Cryptography: Conventional Cryptography and Public Key Cryptography.
- Conventional Cryptography: Also called secret-key or symmetric-key encryption, one key is used both for encryption and decryption. Examples of Conventional Cryptography systems are Caesar's Cipher, Data Encryption Standard. Figure 1 is an illustration of the conventional encryption process.(Conventional Cryptography, 2010)
Figure 1: Conventional Cryptography process
- Public Key Cryptography: Also called symmetric encryption (Cryptography Symmetric). It uses a single key to the process of encryption and decryption of data. This depends on the type of secret encryption key used. As the person who has the decryption key can read the content of messages or files. An example of this; if X wanted to send an encrypted message to the Y, upon finding a safe way to send the key to the Y. If you got any third party on this key, they can read all encrypted messages between X and Y. Examples of Public Key Cryptography systems: DSA ,PGP, RSA. Figure 2 is an illustration of the Public Key Cryptography process.(More about Public Key Infrastructure (PKI), 2010)
Figure 2: Public Key Cryptography process
Advantages and disadvantages of conventional cryptography and cryptography using the public key: Conventional cryptography is much faster than Public Key Cryptography by using modern computer, but it uses only one key. It is more likely to be breakthroughs. The public key cryptography keys is used in the process of encryption and decryption, which is stronger and less prone to breakthroughs, but it is slower than conventional encryption. As a result of these advantages and disadvantages of modern systems now use both methods, where they use the conventional method of encryption and the secret key exchange between the parties per multicast is done through the use of public key encryption method.
Conclusion: Cryptography is giving great interest, since it provides privacy and security of all concepts of data transmitted over open networks. Thus an urgent need for strong encryption methods because with the rapid development of computer, it reduces the strength of encryption, because the increased speed of the computer means shortening the time it takes the computer to break the encryption key or detect a specific encryption key .
References:
- Washington, L. C., & Trappe, W. (2002). Introduction to Cryptography: With Coding Theory. NJ, USA: rentice Hall PTR Upper Saddle River.
- More about Public Key Infrastructure (PKI). (2010). Retrieved 12 4, 2011, from Petri IT Knowledgebase by Daniel Petri: http://www.petri.co.il/public_key_infrastructure_pki.html
- Conventional Cryptography. (2010). Retrieved 12 4, 2011, from ORACLE ThinkQuest - Education Foundation: http://library.thinkquest.org/C0126342/secret.htm
- History of Cryptography. (2010). Retrieved 12 4, 2011, from Logical Security: http://shonharris.net/resources/whitepapers/Cryptography.pdf
Figures:
- Figure 1: Conventional Cryptography process, 2011,retrieved from http://www.calsoftlabs.com/whitepapers/windows-media.html
- Figure 2: Public Key Cryptography process, 2010,retrieved from http://www.data-processing.hk/glossaries/encryption/
