Asymmetric Cryptography

Asymmetric cryptography is also known as Public Key Cryptography. In this system a computer uses two keys in order to securely encrypt and transfer data between two people. The two keys are called the public key, and the private key. The public key is exactly what it sounds like, public. For the system to work the public key must be available to both people. The public key could be posted anywhere online and this system would still function safely and securely.

Then, there is the private key. This key also is named to describe its relation to the process, which is the private half. If this half is in any way compromised then the data being transmitted is no longer safe, and if for any reason a private key is lost then the data become unreadable by the computer, and the data that is sent is lost.

The best way to describe this is with an example. Let's say that there are two people: John and Mary. John has a letter that he wants to give to Mary (the letter represents the data that is being transmitted). However, the letter has sensitive information, and he does not want Hank, the hacker, steal the letter and read it.

So, Mary sends John a special envelope that only she can open (this envelope represents Mary's public key). Anyone can look at this envelope, and it does not matter because Mary is the only one who knows how to open it. Since the envelope it empty, John puts the letter in the envelope and seals it, and when Mary receives the envelope she can open it knowing that no one could have read the letter that John sent her. Then John can give Mary his special envelope, and she can put a reply in his envelope and send it back. This can go back and forth as many times as they want, and as long as the John and Mary never tell anyone the secrets to opening their envelopes, then, their messages will be safe.

Asymmetric, or Public Key, encryption does this same thing but uses long strings of random numbers to do so, and the mathematical improbability of guessing the solution to decrypting a public key is what makes this system so safe. Imagine being a handed a sheet of paper with a number on it that is one hundred digits long, and being asked to figure out the exact math problem that led to that number. Without seeing the math problem before hand, it would take a considerable amount of time to guess the process that led to that specific number. Especially if, when the answer is unlocked, it only reveals a transaction that may only be worth a few hundred or thousand dollars. The work needed to crack the system is not worth the reward.

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