Encryption

Encryption is the garbling of data or message so that it can only be understood by the intended recipient. The intended recipient which could be an individual, a computer or an electronic device must have the key, which is the knowledge to interpret the coded data or message. The data garbling process is also known as encoding, which is based on the old long science of cryptography.

Who needs encryption and why? Encryption is needed by anyone who wants to transmit sensitive data, either through someone, surface mail, telephone, computer network like the internet, etc such that the data or message is not intercepted or read by unintended party. In the computer world, encryption could be used for many reasons amongst:

Also, it is also important to mention that encryption predates the computer age, it has been verified that it was used even in the days of Roman Empire.

Encryption comes in different flavours, it could be mere swapping of letters, words in a message or even placement of words with symbols to something more sophisticated like computer encryption systems, which requires complex algorithms. In helping us to understand the way encryption works, let us use a primitive example, a correspondence from John Doe to his CIC. Pre departure for war, John Doe defined a key with his CIC, as follows:

Key words	Meaning
Dance	war
Rescued	Death
Smooth	bloody
Happy	Sad

Now John Doe writes as an update report:

Sir,

Yesterday, the dance advanced to a smooth stage, unfortunately, three of our men were rescued. Everyone is happy with the situation.

To an onlooker, the message is of no value, but to John Doe's CIC very sad news. Even if this message is sent open, with the exception of the CIC, no one knows exactly what the message says.

In the computer world, encryption is more sophisticated, and more difficult to crack even when many computers are assigned the tasks of decoding encrypted messages. There are basically, two categories of encryption in the computer world:

Symmetric Key
Symmetric key encryption is similar with the John Doe's example above. It requires that communicating computers be identified first, have secret or private keys installed before it will be used for packets encryption and thereafter sent over the network to each other. Once packets are received, each uses the keys to decode the information. Even if the packets are intercepted by another computer, so long as that computer does not have the keys, it can not decode the information.

Public key
Public key encryption works differently from symmetric key encryption, it uses a combination of private and public keys to encrypt and transmit packets. Like the symmetric key encryption, originating and receiving computers must have the private key installed locally. In addition, the originating computer also issues public key to the receiving computer that intends to communicate with it securely. To decode an encrypted message, the receiving computer must use the public key, provided by the originating computer, and its own private key.

The public key encryption is secured and not easy to crack because is based on complex algorithms known as hashing algorithm, which uses large base input numbers called hash values. Note that the higher the base input number the better the encryption, the more secured and less likelihood of such encryption being cracked. Example, a 64-bit key encryption, which has 2 power 64 different combinations, is less complex than a 128-bit encryption as it has 2 power 128 different combinations. Imagine the impossible mission of trying to find the hash value for a 448-bit key encryption that is exploring the possibility of trying 72683872429560700000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000 different combinations, out of which one has the hash value.

One of the most popular usages of public key encryption is in the Internet world. Most secured web services and servers uses internet security protocol know as Secure Sockets Layer (SSL), to transmit sensitive information across the internet. When next you visit a secured website, watch out for an additional "s" to the "Hyper Text Transmission Protocol (http), which is "https", instead of the normal "http". In addition, you also see a small padlock in the status bar at the bottom of the browser window.

What happens normally when you tries to access secured section of a web site is that the server, serving the pages you intend to access, creates a symmetric key and sends it to your computer using public-key encryption. The two computers can then communicate using symmetric-key encryption. Once you finish access the secured section or the website, your computer and the server discards the symmetric key. If you try again to access the website, the whole process is repeated all over again.