Importance of Encryption

It is the process of making information unintelligible to the unauthorized reader. It involves the scrambling of data by use of a mathematical algorithm. Encryption is a process where the cryptographer puts an input plaintext into a codified algorithm and a key to get an output cipher text.

Decryption on the other hand, is the reversing of encryption with the cipher text as the input and the plaintext as the output. The function involves both an algorithm and a key, because it would be difficult and time-consuming to keep coming up with new effective algorithms every time one wants to send a secure message.

1. Encryption uses a code or a cipher.

2. Code system uses a predefined table or dictionary to substitute a meaningless word or phrase for each message or part of a message.

3. Cipher uses a computable algorithm that translates any stream of message bits into an unintelligible cryptogram.

There are three kinds of cryptographic functions:

1. Hash functions (involve the use of no keys).

2. Secret-key functions (involves the use of one key).

3. Public - key function (involves the use of two keys)

Encryption can be private-key or public key:

Private Key entails the encoding and decoding of data with the same key. Since the same key is used to encrypt and decrypt data, the key must be known by both the sender and receiver locations. Using private key encryption provides good security because the receiver must have the key if it is to decrypt the message.

Public key encryption uses two keys, a private key and a public key. One key is used to encrypt messages (public key) and the other is used to decrypt (private key). The public encryption key is made available to who ever wants to use it, but the private key is kept secret by the key owner. Users can send e-mail to the key owner (only) encrypting the message with the recipient's public key. The key owner using the private key then decrypts messages.

Conventional Encryption (Symmetric Cryptography)