An introductory guide to private key and public key encryption

Dear Readers! Greetings for the day!

My younger brother, who was preparing for data encryption examinations told me to write an article on data encryption fundamentals. He wanted to know in detail about data encryption basics. In my previous post, I discussed the need of data encryption in electronic business website. In this post, I plan to fulfill the wish of my brother.

The basics

Data encryption also means data hiding in simple terms. It simply means information exchange between 2 users “privately”. By privately, I mean keeping only these 2 authorized to view / get the information and hiding the information from rest of the world.

While this seems easy to implement on paper but is a challenge in practice.

1. The first user must use a cipher to hide the information. This cipher is known as encryption key in general context.

2. The second user (intended recipient) must use the same cipher to decrypt the information so that he understands the exact information to be sent.

3. In case, the intended recipient does not has the required cipher, this entire process is a big failure.

Managing encryption: The private key encryption

To manage the details, there are 2 different fundamentals: First is the algorithm. It is the series of steps. The second is the key.

The algorithm can be made public. It can be disclosed to even the hacker. But, the key remains a secret. The simplest way to implement this system is Data Encryption Standard DES. The DES is either 48 bit algorithm OR 56 bit depending on the  application

There are 2 major parts – Stream cipher and Block cipher. Stream cipher encrypts 1 bit at a time while block cipher divides the data in blocks and encrypts a block. The DES mainly makes use of Block cipher. I

Managing encryption: The public key encryption

The real challenge with private key is: how to exchange the key. Public Key system answers this case. Both the users must send their public keys to each other and apply the algorithm to encrypt and decrypt.

The most common mechanism is: RSA Algorithm. This algorithm is mainly used in electronic commerce websites today. The so called SSL protocol is actually RSA algorithm only.


Data Encryption fundamentals, that is its keys and algorithms are widely used to hide the data from unauthorized access. Different encryption fundamentals use different key sizes. Generally, a larger key is recommended.

Data Security fundamentals demystified in easy to understand manner.

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