The Basics Of Key Cryptography



This is a guest post by Catalin.

Some might say that I am not qualified enough to do the following task and to some extend I will agree with them. Currently I am employed by an Austin TX SEO firm, with my main function relying on search engine optimization. However, for the purpose of this article I will go over some basics surrounding encryption, namely, the Diffie-Hellman key exchange. This system is employed in public key cryptography.

I will try to keep the article as simple as possible, despite the complexity of the subject at hand. To better understand how public key cryptography works and why it is essential, we will have to understand how exactly the scenario works.

Let us say that you have a file that you wish to share with a friend. As someone that works with an Austin internet marketing company, this happens a lot of time for me. Sometimes these files can contain sensitive information from one of our clients or maybe I do not wish to endanger any of the information found in those files.

If I send the file and it is intercepted, the 3rd party can easily gain access to it. By using a password protection, a simple password protection system, with enough time or processing power, someone can break the password by simply bruteforcing the file. This simply means that you try all possible combinations and the more power your machine or network of machines has, the quicker this will end.

In case of the Diffie-Hellman key exchange, both me and my friend agree on two different numbers that are publicly announced. These can be intercepted, but their meaning is unknown to any third party. In this case, we use modular functions. Modular functions are also known as clock arithmetic, since you take a number and see if you divide a rope to that number resulting in equal units and wind it around a clock, what number the rope ends at.

Now both me and my friend know which function we will use but we share out own personal results. In a sense, we both know the basic elements of the equation and our own individual exponents. By sharing our own personal results, we can calculate what the others’ private exponent is, then we combine our own personal exponent with our friends exponent and apply that to the basic elements of the equation.

If a third party were to “listen in” they would only get our publicly share results which are based on our own calculations. However, they cannot backtrack that system to find out what our own private keys were. The other highly important element is that no user has access to both keys from the start. Each key is private and personal and the only information officially shared cannot be used to track any of the two numbers.

This however is not entirely true, since you could bruteforce this as well. Unlike simple password encryption though, this can literally take thousands of years even with the most advanced computers in the world. The system is easy in one direction (from me to my friend and vice versa) but it is close to impossible in the other direction.

About the author:

Catalin works for an Austin TX SEO company, providing clients with the best solutions for their business. If you are looking for any Austin internet marketing company, the one he works at will be your first recommendation.

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