Encryption technology:

Encryption technology is an effective information security protection. It is defined as converting a Plaintext into meaningless Ciphertext using encryption algorithm thus ensuring the confidentiality of the data. The encryption or decryption process use a key to encrypt or decrypt the data. At present, two encryption technologies are widely used. They are symmetric key encryption system and an asymmetric key encryption system.

Symmetric key encryption:

The Data Encryption Standard (DES) is a Symmetric key data encryption method. It was introduced in America in the year 1976, by Federal Information Processing Standard (FIPS).

DES is the typical block algorithm that takes a string of bits of cleartext (plaintext) with a fixed length and, through a series of complicated operations, transforms it into another encrypted text of the same length. DES also uses a key to customize the transformation, so that, in theory, the algorithm can only be deciphered by people who know the exact key that has been used for encryption. The DES key is apparently 64 bits, but in fact the algorithm uses only 56. The other eight bits are only used to verify the parity and then it is discarded.

Today, it is considered that DES is not safe for many applications, mainly because of its relatively smaller key size (56-bit). But the key length can be easily increased by multiple use of the DES, described as Triple-DES, also known as TDES, 3DES or DESede.

Asymmetric or Public key encryption:

Asymmetric encryption also called as RSA (RivestShamir-Adleman) algorithm. It uses public- key authentication and digital signatures. Until 1970s, there were only symmetric cryptosystems in which transmitter and receiver must have the same key. This raises the problem of key exchange andJcey management.

Unlike a symmetric encryption, the communicating parties need not know other’s private- key in asymmetric encryption. Each user generates their own key pair, which consists of a private key and a public key. A public-key encryption method is a method for converting a plaintext with a public key into a ciphertext from which the plaintext can be retrieved with a private key.